diff --git a/php/_1broker.php b/php/_1broker.php
index 80d66237f6cd9..028133ee94023 100644
--- a/php/_1broker.php
+++ b/php/_1broker.php
@@ -29,6 +29,10 @@ public function describe () {
                 'www' => 'https://1broker.com',
                 'doc' => 'https://1broker.com/?c=en/content/api-documentation',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => false,
+            ),
             'api' => array (
                 'private' => array (
                     'get' => array (
@@ -239,8 +243,7 @@ public function cancel_order ($id, $symbol = null, $params = array ()) {
     }
 
     public function sign ($path, $api = 'public', $method = 'GET', $params = array (), $headers = null, $body = null) {
-        if (!$this->apiKey)
-            throw new AuthenticationError ($this->id . ' requires apiKey for all requests');
+        $this->check_required_credentials();
         $url = $this->urls['api'] . '/' . $this->version . '/' . $path . '.php';
         $query = array_merge (array ( 'token' => $this->apiKey ), $params);
         $url .= '?' . $this->urlencode ($query);
diff --git a/php/_1btcxe.php b/php/_1btcxe.php
index e657454187f97..02ed5894dd05a 100644
--- a/php/_1btcxe.php
+++ b/php/_1btcxe.php
@@ -220,6 +220,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $query = array_merge (array (
                 'api_key' => $this->apiKey,
                 'nonce' => $this->nonce (),
diff --git a/php/acx.php b/php/acx.php
index e40c2cde940f7..e92a39160ae6e 100644
--- a/php/acx.php
+++ b/php/acx.php
@@ -299,6 +299,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $query = $this->urlencode ($this->keysort (array_merge (array (
                 'access_key' => $this->apiKey,
diff --git a/php/anxpro.php b/php/anxpro.php
index 414150052b2a0..41fc8e67928fd 100644
--- a/php/anxpro.php
+++ b/php/anxpro.php
@@ -176,6 +176,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array ( 'nonce' => $nonce ), $query));
             $secret = base64_decode ($this->secret);
diff --git a/php/binance.php b/php/binance.php
index 9c1205db19634..b184e1dc9b986 100644
--- a/php/binance.php
+++ b/php/binance.php
@@ -579,6 +579,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'wapi')
             $url .= '.html';
         if (($api == 'private') || ($api == 'wapi')) {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $query = $this->urlencode (array_merge (array ( 'timestamp' => $nonce ), $params));
             $signature = null;
diff --git a/php/bit2c.php b/php/bit2c.php
index aeb85f31b0174..ca4661666b3ff 100644
--- a/php/bit2c.php
+++ b/php/bit2c.php
@@ -172,6 +172,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= '.json';
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $query = array_merge (array ( 'nonce' => $nonce ), $params);
             $body = $this->urlencode ($query);
diff --git a/php/bitbay.php b/php/bitbay.php
index f17f92583dcf5..385219f60de49 100644
--- a/php/bitbay.php
+++ b/php/bitbay.php
@@ -211,6 +211,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= '/' . $this->implode_params($path, $params) . '.json';
         } else {
+            $this->check_required_credentials();
             $body = $this->urlencode (array_merge (array (
                 'method' => $path,
                 'moment' => $this->nonce (),
diff --git a/php/bitcoincoid.php b/php/bitcoincoid.php
index 094899261d751..659273dc2df78 100644
--- a/php/bitcoincoid.php
+++ b/php/bitcoincoid.php
@@ -167,6 +167,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= '/' . $this->implode_params($path, $params);
         } else {
+            $this->check_required_credentials();
             $body = $this->urlencode (array_merge (array (
                 'method' => $path,
                 'nonce' => $this->nonce (),
diff --git a/php/bitfinex.php b/php/bitfinex.php
index a4ed80d822b8a..4b6d03d4091d5 100644
--- a/php/bitfinex.php
+++ b/php/bitfinex.php
@@ -511,6 +511,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             }
         }
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $query = array_merge (array (
                 'nonce' => (string) $nonce,
diff --git a/php/bitfinex2.php b/php/bitfinex2.php
index 8bafa7efdbe42..361e53df37881 100644
--- a/php/bitfinex2.php
+++ b/php/bitfinex2.php
@@ -381,6 +381,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
                 $url .= '?' . $this->urlencode ($query);
             }
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $body = $this->json ($query);
             $auth = '/api' . '/' . $request . $nonce . $body;
diff --git a/php/bitflyer.php b/php/bitflyer.php
index 4353b38289e6f..9e442c5e881e6 100644
--- a/php/bitflyer.php
+++ b/php/bitflyer.php
@@ -244,6 +244,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         }
         $url = $this->urls['api'] . $request;
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $body = $this->json ($params);
             $auth = implode ('', array ($nonce, $method, $request, $body));
diff --git a/php/bithumb.php b/php/bithumb.php
index 67f41e7248e7a..0848b4d331a7e 100644
--- a/php/bithumb.php
+++ b/php/bithumb.php
@@ -232,6 +232,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $body = $this->urlencode (array_merge (array (
                 'endpoint' => $endpoint,
             ), $query));
diff --git a/php/bitlish.php b/php/bitlish.php
index 0c3f683585fe4..2ad2ad86c0b99 100644
--- a/php/bitlish.php
+++ b/php/bitlish.php
@@ -23,6 +23,10 @@ public function describe () {
                 'www' => 'https://bitlish.com',
                 'doc' => 'https://bitlish.com/api',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => false,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -297,6 +301,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
                 $headers = array ( 'Content-Type' => 'application/json' );
             }
         } else {
+            $this->check_required_credentials();
             $body = $this->json (array_merge (array ( 'token' => $this->apiKey ), $params));
             $headers = array ( 'Content-Type' => 'application/json' );
         }
diff --git a/php/bitmarket.php b/php/bitmarket.php
index 6c9f8d8b19d80..9219475492352 100644
--- a/php/bitmarket.php
+++ b/php/bitmarket.php
@@ -286,6 +286,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= '/' . $this->implode_params($path . '.json', $params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $query = array_merge (array (
                 'tonce' => $nonce,
diff --git a/php/bitmex.php b/php/bitmex.php
index db07ee6320abc..17aba9e02c050 100644
--- a/php/bitmex.php
+++ b/php/bitmex.php
@@ -398,6 +398,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             $query .= '?' . $this->urlencode ($params);
         $url = $this->urls['api'] . $query;
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             if ($method == 'POST')
                 if ($params)
diff --git a/php/bitso.php b/php/bitso.php
index 881ad69e55d9c..01b39bf49e592 100644
--- a/php/bitso.php
+++ b/php/bitso.php
@@ -233,6 +233,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $request = implode ('', array ($nonce, $method, $query));
             if ($params) {
diff --git a/php/bitstamp.php b/php/bitstamp.php
index 71593eaaf9ee8..72d73dfe4d246 100644
--- a/php/bitstamp.php
+++ b/php/bitstamp.php
@@ -21,6 +21,11 @@ public function describe () {
                 'www' => 'https://www.bitstamp.net',
                 'doc' => 'https://www.bitstamp.net/api',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -253,8 +258,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
-            if (!$this->uid)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.uid` property for authentication');
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $auth = $nonce . $this->uid . $this->apiKey;
             $signature = $this->encode ($this->hmac ($this->encode ($auth), $this->encode ($this->secret)));
diff --git a/php/bitstamp1.php b/php/bitstamp1.php
index 4f586b1a723fb..8935226647030 100644
--- a/php/bitstamp1.php
+++ b/php/bitstamp1.php
@@ -20,6 +20,11 @@ public function describe () {
                 'www' => 'https://www.bitstamp.net',
                 'doc' => 'https://www.bitstamp.net/api',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -220,8 +225,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
-            if (!$this->uid)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.uid` property for authentication');
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $auth = $nonce . $this->uid . $this->apiKey;
             $signature = $this->encode ($this->hmac ($this->encode ($auth), $this->encode ($this->secret)));
diff --git a/php/bittrex.php b/php/bittrex.php
index 606039497d052..b7f083f44e3a1 100644
--- a/php/bittrex.php
+++ b/php/bittrex.php
@@ -546,6 +546,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $url .= $api . '/';
             if ((($api == 'account') && ($path != 'withdraw')) || ($path == 'openorders'))
diff --git a/php/bl3p.php b/php/bl3p.php
index 7e69bd2d1cc1b..0d46165406c01 100644
--- a/php/bl3p.php
+++ b/php/bl3p.php
@@ -183,6 +183,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array ( 'nonce' => $nonce ), $query));
             $secret = base64_decode ($this->secret);
diff --git a/php/btcbox.php b/php/btcbox.php
index 4f6a3cb3850f5..6e110649db240 100644
--- a/php/btcbox.php
+++ b/php/btcbox.php
@@ -193,6 +193,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $query = array_merge (array (
                 'key' => $this->apiKey,
diff --git a/php/btcchina.php b/php/btcchina.php
index d0224a8ab935f..c28e2bb35a437 100644
--- a/php/btcchina.php
+++ b/php/btcchina.php
@@ -299,10 +299,7 @@ public function nonce () {
     public function sign ($path, $api = 'public', $method = 'GET', $params = array (), $headers = null, $body = null) {
         $url = $this->urls['api'][$api] . '/' . $path;
         if ($api == 'private') {
-            if (!$this->apiKey)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.apiKey` property for authentication');
-            if (!$this->secret)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.secret` property for authentication');
+            $this->check_required_credentials();
             $p = array ();
             if (array_key_exists ('params', $params))
                 $p = $params['params'];
diff --git a/php/btcmarkets.php b/php/btcmarkets.php
index b000d93be79d0..1b9e8f6221172 100644
--- a/php/btcmarkets.php
+++ b/php/btcmarkets.php
@@ -197,6 +197,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $auth = $uri . "\n" . $nonce . "\n";
             $headers = array (
diff --git a/php/btctradeua.php b/php/btctradeua.php
index 488142aed3aa6..bf162bbd5d83c 100644
--- a/php/btctradeua.php
+++ b/php/btctradeua.php
@@ -304,6 +304,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= $this->implode_params($path, $query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array (
                 'out_order_id' => $nonce,
diff --git a/php/btcturk.php b/php/btcturk.php
index 042a9c81c2b54..d7c60514030b3 100644
--- a/php/btcturk.php
+++ b/php/btcturk.php
@@ -216,6 +216,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ().toString;
             $body = $this->urlencode ($params);
             $secret = $this->base64ToString ($this->secret);
diff --git a/php/btcx.php b/php/btcx.php
index ca762f08c5db5..48f77305fb1be 100644
--- a/php/btcx.php
+++ b/php/btcx.php
@@ -146,6 +146,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= $this->implode_params($path, $params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $url .= $api;
             $body = $this->urlencode (array_merge (array (
diff --git a/php/bter.php b/php/bter.php
index ee9bbe0cf0a6b..e3aaade2a7d00 100644
--- a/php/bter.php
+++ b/php/bter.php
@@ -265,6 +265,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $request = array ( 'nonce' => $nonce );
             $body = $this->urlencode (array_merge ($request, $query));
diff --git a/php/bxinth.php b/php/bxinth.php
index 73d45c279504b..2b14addc60157 100644
--- a/php/bxinth.php
+++ b/php/bxinth.php
@@ -234,6 +234,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($params)
             $url .= '?' . $this->urlencode ($params);
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $auth = $this->apiKey . (string) $nonce . $this->secret;
             $signature = $this->hash ($this->encode ($auth), 'sha256');
diff --git a/php/ccex.php b/php/ccex.php
index 0e62c50e8b713..2a95b641da08d 100644
--- a/php/ccex.php
+++ b/php/ccex.php
@@ -239,6 +239,7 @@ public function cancel_order ($id, $symbol = null, $params = array ()) {
     public function sign ($path, $api = 'public', $method = 'GET', $params = array (), $headers = null, $body = null) {
         $url = $this->urls['api'][$api];
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $query = $this->keysort (array_merge (array (
                 'a' => $path,
diff --git a/php/cex.php b/php/cex.php
index d6aedf9f19b1f..236ba1651d95c 100644
--- a/php/cex.php
+++ b/php/cex.php
@@ -25,6 +25,11 @@ public function describe () {
                 'www' => 'https://cex.io',
                 'doc' => 'https://cex.io/cex-api',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -381,8 +386,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
-            if (!$this->uid)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.uid` property for authentication');
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $auth = $nonce . $this->uid . $this->apiKey;
             $signature = $this->hmac ($this->encode ($auth), $this->encode ($this->secret));
diff --git a/php/coincheck.php b/php/coincheck.php
index 7668a656daf43..99e54d3f55f69 100644
--- a/php/coincheck.php
+++ b/php/coincheck.php
@@ -199,6 +199,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             if ($query)
                 $body = $this->urlencode ($this->keysort ($query));
diff --git a/php/coinfloor.php b/php/coinfloor.php
index 4c8ba317bc9f8..18ae90ec96c77 100644
--- a/php/coinfloor.php
+++ b/php/coinfloor.php
@@ -22,6 +22,11 @@ public function describe () {
                     'https://www.coinfloor.co.uk/api',
                 ),
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -164,6 +169,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array ( 'nonce' => $nonce ), $query));
             $auth = $this->uid . '/' . $this->apiKey . ':' . $this->password;
diff --git a/php/coingi.php b/php/coingi.php
index cfb0dccfa17e9..984aaff29d8dc 100644
--- a/php/coingi.php
+++ b/php/coingi.php
@@ -200,6 +200,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $request = array_merge (array (
                 'token' => $this->apiKey,
diff --git a/php/coinmarketcap.php b/php/coinmarketcap.php
index 12b81691d8e41..aaef8cae2c4ee 100644
--- a/php/coinmarketcap.php
+++ b/php/coinmarketcap.php
@@ -27,6 +27,10 @@ public function describe () {
                 'www' => 'https://coinmarketcap.com',
                 'doc' => 'https://coinmarketcap.com/api',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => false,
+                'secret' => false,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
diff --git a/php/coinmate.php b/php/coinmate.php
index 4b27dc5d88cdd..268e60356b0b0 100644
--- a/php/coinmate.php
+++ b/php/coinmate.php
@@ -22,6 +22,11 @@ public function describe () {
                     'https://coinmate.io/developers',
                 ),
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -176,8 +181,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
-            if (!$this->uid)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.uid` property for authentication');
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $auth = $nonce . $this->uid . $this->apiKey;
             $signature = $this->hmac ($this->encode ($auth), $this->encode ($this->secret));
diff --git a/php/coinsecure.php b/php/coinsecure.php
index 88eb834e0edce..60686989e3f1c 100644
--- a/php/coinsecure.php
+++ b/php/coinsecure.php
@@ -23,6 +23,10 @@ public function describe () {
                     'https://github.com/coinsecure/plugins',
                 ),
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => false,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -261,6 +265,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         $url = $this->urls['api'] . '/' . $this->version . '/' . $this->implode_params($path, $params);
         $query = $this->omit ($params, $this->extract_params($path));
         if ($api == 'private') {
+            $this->check_required_credentials();
             $headers = array ( 'Authorization' => $this->apiKey );
             if ($query) {
                 $body = $this->json ($query);
diff --git a/php/coinspot.php b/php/coinspot.php
index bb96d1b9f10eb..b9d4cc9f391e4 100644
--- a/php/coinspot.php
+++ b/php/coinspot.php
@@ -143,6 +143,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             throw new AuthenticationError ($this->id . ' requires apiKey for all requests');
         $url = $this->urls['api'][$api] . '/' . $path;
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->json (array_merge (array ( 'nonce' => $nonce ), $params));
             $headers = array (
diff --git a/php/cryptopia.php b/php/cryptopia.php
index 86af6af7730bd..77e8249f8c7f6 100644
--- a/php/cryptopia.php
+++ b/php/cryptopia.php
@@ -496,6 +496,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $body = $this->json ($query);
             $hash = $this->hash ($this->encode ($body), 'md5', 'base64');
diff --git a/php/exmo.php b/php/exmo.php
index 29e12145f2964..d1143a4c5b9d1 100644
--- a/php/exmo.php
+++ b/php/exmo.php
@@ -246,6 +246,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array ( 'nonce' => $nonce ), $params));
             $headers = array (
diff --git a/php/flowbtc.php b/php/flowbtc.php
index cb46c12c1e047..7650e6c5951ed 100644
--- a/php/flowbtc.php
+++ b/php/flowbtc.php
@@ -20,6 +20,11 @@ public function describe () {
                 'www' => 'https://trader.flowbtc.com',
                 'doc' => 'http://www.flowbtc.com.br/api/',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'post' => array (
@@ -191,8 +196,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
                 $body = $this->json ($params);
             }
         } else {
-            if (!$this->uid)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.uid` property for authentication');
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $auth = (string) $nonce . $this->uid . $this->apiKey;
             $signature = $this->hmac ($this->encode ($auth), $this->encode ($this->secret));
diff --git a/php/foxbit.php b/php/foxbit.php
index 4d255fe52df37..b6e6d371470e2 100644
--- a/php/foxbit.php
+++ b/php/foxbit.php
@@ -164,6 +164,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $request = array_merge (array ( 'MsgType' => $path ), $query);
             $body = $this->json ($request);
diff --git a/php/fybse.php b/php/fybse.php
index d90988a23f65d..fe4eb54fa2efd 100644
--- a/php/fybse.php
+++ b/php/fybse.php
@@ -147,6 +147,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= '.json';
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array ( 'timestamp' => $nonce ), $params));
             $headers = array (
diff --git a/php/gatecoin.php b/php/gatecoin.php
index 21edfaceade43..2072534ce784c 100644
--- a/php/gatecoin.php
+++ b/php/gatecoin.php
@@ -381,6 +381,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $contentType = ($method == 'GET') ? '' : 'application/json';
             $auth = $method . $url . $contentType . (string) $nonce;
diff --git a/php/gdax.php b/php/gdax.php
index e740a7382ecf3..fabbdf61cab08 100644
--- a/php/gdax.php
+++ b/php/gdax.php
@@ -41,6 +41,11 @@ public function describe () {
                 'www' => 'https://www.gdax.com',
                 'doc' => 'https://docs.gdax.com',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'password' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -451,12 +456,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         }
         $url = $this->urls['api'] . $request;
         if ($api == 'private') {
-            if (!$this->apiKey)
-                throw new AuthenticationError ($this->id . ' requires apiKey property for authentication and trading');
-            if (!$this->secret)
-                throw new AuthenticationError ($this->id . ' requires $secret property for authentication and trading');
-            if (!$this->password)
-                throw new AuthenticationError ($this->id . ' requires password property for authentication and trading');
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $payload = '';
             if ($method != 'GET') {
diff --git a/php/gemini.php b/php/gemini.php
index 484ec93f41a43..64c6330ff50ca 100644
--- a/php/gemini.php
+++ b/php/gemini.php
@@ -186,6 +186,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $request = array_merge (array (
                 'request' => $url,
diff --git a/php/hitbtc.php b/php/hitbtc.php
index ffc2b64da0731..8fc54845d0432 100644
--- a/php/hitbtc.php
+++ b/php/hitbtc.php
@@ -383,6 +383,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $payload = array ( 'nonce' => $nonce, 'apikey' => $this->apiKey );
             $query = array_merge ($payload, $query);
diff --git a/php/hitbtc2.php b/php/hitbtc2.php
index 5b24056385101..81aa7ce8d3f95 100644
--- a/php/hitbtc2.php
+++ b/php/hitbtc2.php
@@ -495,6 +495,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $url .= $this->implode_params($path, $params);
             if ($method == 'GET') {
                 if ($query)
diff --git a/php/huobi.php b/php/huobi.php
index 155804c2196ef..0adf03bdb8b80 100644
--- a/php/huobi.php
+++ b/php/huobi.php
@@ -215,6 +215,7 @@ public function cancel_order ($id, $symbol = null, $params = array ()) {
     public function sign ($path, $api = 'public', $method = 'GET', $params = array (), $headers = null, $body = null) {
         $url = $this->urls['api'];
         if ($api == 'trade') {
+            $this->check_required_credentials();
             $url .= '/api' . $this->version;
             $query = $this->keysort (array_merge (array (
                 'method' => $path,
diff --git a/php/huobipro.php b/php/huobipro.php
index e1ca144fe96e8..2188df2260eb4 100644
--- a/php/huobipro.php
+++ b/php/huobipro.php
@@ -331,6 +331,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         $url .= '/' . $this->implode_params($path, $params);
         $query = $this->omit ($params, $this->extract_params($path));
         if ($api == 'private') {
+            $this->check_required_credentials();
             $timestamp = $this->YmdHMS ($this->milliseconds (), 'T');
             $request = $this->keysort (array_merge (array (
                 'SignatureMethod' => 'HmacSHA256',
diff --git a/php/independentreserve.php b/php/independentreserve.php
index 77e63ada85263..4655b62ce1f3e 100644
--- a/php/independentreserve.php
+++ b/php/independentreserve.php
@@ -219,6 +219,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $auth = array (
                 $url,
diff --git a/php/itbit.php b/php/itbit.php
index 92d14ca84fa86..754444a6831f2 100644
--- a/php/itbit.php
+++ b/php/itbit.php
@@ -199,6 +199,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             if ($query)
                 $body = $this->json ($query);
             else
diff --git a/php/kraken.php b/php/kraken.php
index 70e7138bce136..5300a95105d05 100644
--- a/php/kraken.php
+++ b/php/kraken.php
@@ -576,6 +576,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $body = $this->urlencode (array_merge (array ( 'nonce' => $nonce ), $params));
             $auth = $this->encode ($nonce . $body);
diff --git a/php/lakebtc.php b/php/lakebtc.php
index 0e99696152291..a647550a147c0 100644
--- a/php/lakebtc.php
+++ b/php/lakebtc.php
@@ -189,6 +189,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             if ($params)
                 $params = implode (',', $params);
diff --git a/php/liqui.php b/php/liqui.php
index e51d4f91f0f24..239aafc110340 100644
--- a/php/liqui.php
+++ b/php/liqui.php
@@ -566,6 +566,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         $url = $this->urls['api'][$api];
         $query = $this->omit ($params, $this->extract_params($path));
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array (
                 'nonce' => $nonce,
diff --git a/php/livecoin.php b/php/livecoin.php
index ae49509de2846..b8098193d7a1c 100644
--- a/php/livecoin.php
+++ b/php/livecoin.php
@@ -236,6 +236,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             }
         }
         if ($api == 'private') {
+            $this->check_required_credentials();
             if ($method == 'POST')
                 $body = $query;
             $signature = $this->hmac ($this->encode ($query), $this->encode ($this->secret), 'sha256');
diff --git a/php/luno.php b/php/luno.php
index f47379295566d..f53a44ebe258c 100644
--- a/php/luno.php
+++ b/php/luno.php
@@ -238,6 +238,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($query)
             $url .= '?' . $this->urlencode ($query);
         if ($api == 'private') {
+            $this->check_required_credentials();
             $auth = $this->encode ($this->apiKey . ':' . $this->secret);
             $auth = base64_encode ($auth);
             $headers = array ( 'Authorization' => 'Basic ' . $this->decode ($auth) );
diff --git a/php/mercado.php b/php/mercado.php
index 960d842a3e91c..94acf1774142e 100644
--- a/php/mercado.php
+++ b/php/mercado.php
@@ -190,6 +190,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= $this->implode_params($path, $params);
         } else {
+            $this->check_required_credentials();
             $url .= $this->version . '/';
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array (
diff --git a/php/mixcoins.php b/php/mixcoins.php
index 0965382ee7a0d..cbb82b6e0095a 100644
--- a/php/mixcoins.php
+++ b/php/mixcoins.php
@@ -155,6 +155,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $body = $this->urlencode (array_merge (array (
                 'nonce' => $nonce,
diff --git a/php/nova.php b/php/nova.php
index 0c136587d3ac2..70bd80f30a979 100644
--- a/php/nova.php
+++ b/php/nova.php
@@ -198,6 +198,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $url .= '?' . $this->urlencode (array ( 'nonce' => $nonce ));
             $signature = $this->hmac ($this->encode ($url), $this->encode ($this->secret), 'sha512', 'base64');
diff --git a/php/okcoinusd.php b/php/okcoinusd.php
index 82cd7a8fd09bd..2cddc9b6d8703 100644
--- a/php/okcoinusd.php
+++ b/php/okcoinusd.php
@@ -529,6 +529,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             $url .= $this->version . '/';
         $url .= $path . $this->extension;
         if ($api == 'private') {
+            $this->check_required_credentials();
             $query = $this->keysort (array_merge (array (
                 'api_key' => $this->apiKey,
             ), $params));
diff --git a/php/paymium.php b/php/paymium.php
index 765b44023ff1e..b74f239e0f545 100644
--- a/php/paymium.php
+++ b/php/paymium.php
@@ -181,6 +181,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $body = $this->json ($params);
             $nonce = (string) $this->nonce ();
             $auth = $nonce . $url . $body;
diff --git a/php/poloniex.php b/php/poloniex.php
index 4f5dc495eb94c..7e575c03d3afd 100644
--- a/php/poloniex.php
+++ b/php/poloniex.php
@@ -610,6 +610,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $query['nonce'] = $this->nonce ();
             $body = $this->urlencode ($query);
             $headers = array (
diff --git a/php/qryptos.php b/php/qryptos.php
index 867d19f20b785..a43cdd057058c 100644
--- a/php/qryptos.php
+++ b/php/qryptos.php
@@ -240,6 +240,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $request = array (
                 'path' => $url,
diff --git a/php/quadrigacx.php b/php/quadrigacx.php
index 2b86b6d3efb8c..5f4b7a0ff35ea 100644
--- a/php/quadrigacx.php
+++ b/php/quadrigacx.php
@@ -20,6 +20,11 @@ public function describe () {
                 'www' => 'https://www.quadrigacx.com',
                 'doc' => 'https://www.quadrigacx.com/api_info',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -159,8 +164,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= '?' . $this->urlencode ($params);
         } else {
-            if (!$this->uid)
-                throw new AuthenticationError ($this->id . ' requires `' . $this->id . '.uid` property for authentication');
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $request = implode ('', array ((string) $nonce, $this->uid, $this->apiKey));
             $signature = $this->hmac ($this->encode ($request), $this->encode ($this->secret));
diff --git a/php/southxchange.php b/php/southxchange.php
index 963e6af666bd3..57362743522c7 100644
--- a/php/southxchange.php
+++ b/php/southxchange.php
@@ -213,6 +213,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         $url = $this->urls['api'] . '/' . $this->implode_params($path, $params);
         $query = $this->omit ($params, $this->extract_params($path));
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $query = array_merge (array (
                 'key' => $this->apiKey,
diff --git a/php/therock.php b/php/therock.php
index b5809180a071b..2d20584045ef1 100644
--- a/php/therock.php
+++ b/php/therock.php
@@ -227,6 +227,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         $url = $this->urls['api'] . '/' . $this->version . '/' . $this->implode_params($path, $params);
         $query = $this->omit ($params, $this->extract_params($path));
         if ($api == 'private') {
+            $this->check_required_credentials();
             $nonce = (string) $this->nonce ();
             $auth = $nonce . $url;
             $headers = array (
diff --git a/php/vaultoro.php b/php/vaultoro.php
index f8ff7a5e2d3a1..6bba4e9884a46 100644
--- a/php/vaultoro.php
+++ b/php/vaultoro.php
@@ -190,6 +190,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if ($api == 'public') {
             $url .= $path;
         } else {
+            $this->check_required_credentials();
             $nonce = $this->nonce ();
             $url .= $this->version . '/' . $this->implode_params($path, $params);
             $query = array_merge (array (
diff --git a/php/virwox.php b/php/virwox.php
index d7f2d507a713a..8f236cfb05ce5 100644
--- a/php/virwox.php
+++ b/php/virwox.php
@@ -22,6 +22,12 @@ public function describe () {
                 'www' => 'https://www.virwox.com',
                 'doc' => 'https://www.virwox.com/developers.php',
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => false,
+                'login' => true,
+                'password' => true
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -208,6 +214,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         $url = $this->urls['api'][$api];
         $auth = array ();
         if ($api == 'private') {
+            $this->check_required_credentials();
             $auth['key'] = $this->apiKey;
             $auth['user'] = $this->login;
             $auth['pass'] = $this->password;
diff --git a/php/xbtce.php b/php/xbtce.php
index 0a4b48c8b9408..94ed623401b88 100644
--- a/php/xbtce.php
+++ b/php/xbtce.php
@@ -26,6 +26,11 @@ public function describe () {
                     'https://support.xbtce.info/Knowledgebase/Article/View/52/25/xbtce-exchange-api',
                 ),
             ),
+            'requiredCredentials' => array (
+                'apiKey' => true,
+                'secret' => true,
+                'uid' => true,
+            ),
             'api' => array (
                 'public' => array (
                     'get' => array (
@@ -300,7 +305,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         if (!$this->apiKey)
             throw new AuthenticationError ($this->id . ' requires apiKey for all requests, their public API is always busy');
         if (!$this->uid)
-            throw new AuthenticationError ($this->id . ' requires uid property for authentication and trading');
+            throw new AuthenticationError ($this->id . ' requires uid property for authentication and trading, their public API is always busy');
         $url = $this->urls['api'] . '/' . $this->version;
         if ($api == 'public')
             $url .= '/' . $api;
@@ -310,15 +315,16 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($query)
                 $url .= '?' . $this->urlencode ($query);
         } else {
+            $this->check_required_credentials();
             $headers = array ( 'Accept-Encoding' => 'gzip, deflate' );
             $nonce = (string) $this->nonce ();
             if ($method == 'POST') {
                 if ($query) {
                     $headers['Content-Type'] = 'application/json';
                     $body = $this->json ($query);
-                }
-                else
+                } else {
                     $url .= '?' . $this->urlencode ($query);
+                }
             }
             $auth = $nonce . $this->uid . $this->apiKey . $method . $url;
             if ($body)
diff --git a/php/zaif.php b/php/zaif.php
index 2aa2dc884251f..6fcda439f5df4 100644
--- a/php/zaif.php
+++ b/php/zaif.php
@@ -321,6 +321,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
         } else if ($api == 'fapi') {
             $url .= 'fapi/' . $this->version . '/' . $this->implode_params($path, $params);
         } else {
+            $this->check_required_credentials();
             if ($api == 'ecapi') {
                 $url .= 'ecapi';
             } else if ($api == 'tlapi') {
diff --git a/php/zb.php b/php/zb.php
index f79aba7ba2c49..cbed41098e3f6 100644
--- a/php/zb.php
+++ b/php/zb.php
@@ -275,6 +275,7 @@ public function sign ($path, $api = 'public', $method = 'GET', $params = array (
             if ($params)
                 $url .= '?' . $this->urlencode ($params);
         } else {
+            $this->check_required_credentials();
             $paramsLength = count ($params); // $params should be a string here
             $nonce = $this->nonce ();
             $auth = 'method=' . $path;
diff --git a/python/ccxt/_1broker.py b/python/ccxt/_1broker.py
index b8d7c022aa3cd..0ae00886d5e88 100644
--- a/python/ccxt/_1broker.py
+++ b/python/ccxt/_1broker.py
@@ -2,7 +2,6 @@
 
 from ccxt.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class _1broker (Exchange):
@@ -30,6 +29,10 @@ def describe(self):
                 'www': 'https://1broker.com',
                 'doc': 'https://1broker.com/?c=en/content/api-documentation',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+            },
             'api': {
                 'private': {
                     'get': [
@@ -224,8 +227,7 @@ def cancel_order(self, id, symbol=None, params={}):
         return self.privatePostOrderCancel({'order_id': id})
 
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
-        if not self.apiKey:
-            raise AuthenticationError(self.id + ' requires apiKey for all requests')
+        self.check_required_credentials()
         url = self.urls['api'] + '/' + self.version + '/' + path + '.php'
         query = self.extend({'token': self.apiKey}, params)
         url += '?' + self.urlencode(query)
diff --git a/python/ccxt/_1btcxe.py b/python/ccxt/_1btcxe.py
index 650734c362cbe..5adfb19d56a93 100644
--- a/python/ccxt/_1btcxe.py
+++ b/python/ccxt/_1btcxe.py
@@ -208,6 +208,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             query = self.extend({
                 'api_key': self.apiKey,
                 'nonce': self.nonce(),
diff --git a/python/ccxt/acx.py b/python/ccxt/acx.py
index 66a1432101cc5..95cbc0f24836d 100644
--- a/python/ccxt/acx.py
+++ b/python/ccxt/acx.py
@@ -279,6 +279,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             query = self.urlencode(self.keysort(self.extend({
                 'access_key': self.apiKey,
diff --git a/python/ccxt/anxpro.py b/python/ccxt/anxpro.py
index 87395ae8c2b6f..e7ca5d8ab5462 100644
--- a/python/ccxt/anxpro.py
+++ b/python/ccxt/anxpro.py
@@ -167,6 +167,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, query))
             secret = base64.b64decode(self.secret)
diff --git a/python/ccxt/async/_1broker.py b/python/ccxt/async/_1broker.py
index 81ecba47e9679..c006e14673c02 100644
--- a/python/ccxt/async/_1broker.py
+++ b/python/ccxt/async/_1broker.py
@@ -2,7 +2,6 @@
 
 from ccxt.async.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class _1broker (Exchange):
@@ -30,6 +29,10 @@ def describe(self):
                 'www': 'https://1broker.com',
                 'doc': 'https://1broker.com/?c=en/content/api-documentation',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+            },
             'api': {
                 'private': {
                     'get': [
@@ -224,8 +227,7 @@ async def cancel_order(self, id, symbol=None, params={}):
         return await self.privatePostOrderCancel({'order_id': id})
 
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
-        if not self.apiKey:
-            raise AuthenticationError(self.id + ' requires apiKey for all requests')
+        self.check_required_credentials()
         url = self.urls['api'] + '/' + self.version + '/' + path + '.php'
         query = self.extend({'token': self.apiKey}, params)
         url += '?' + self.urlencode(query)
diff --git a/python/ccxt/async/_1btcxe.py b/python/ccxt/async/_1btcxe.py
index 0d9892021da44..15c0785c1830d 100644
--- a/python/ccxt/async/_1btcxe.py
+++ b/python/ccxt/async/_1btcxe.py
@@ -208,6 +208,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             query = self.extend({
                 'api_key': self.apiKey,
                 'nonce': self.nonce(),
diff --git a/python/ccxt/async/acx.py b/python/ccxt/async/acx.py
index 27bce64163b21..8b858c145f4c3 100644
--- a/python/ccxt/async/acx.py
+++ b/python/ccxt/async/acx.py
@@ -279,6 +279,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             query = self.urlencode(self.keysort(self.extend({
                 'access_key': self.apiKey,
diff --git a/python/ccxt/async/anxpro.py b/python/ccxt/async/anxpro.py
index 229e89034d944..599262280478a 100644
--- a/python/ccxt/async/anxpro.py
+++ b/python/ccxt/async/anxpro.py
@@ -167,6 +167,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, query))
             secret = base64.b64decode(self.secret)
diff --git a/python/ccxt/async/binance.py b/python/ccxt/async/binance.py
index bf7cbf0868652..e5f57aadcd221 100644
--- a/python/ccxt/async/binance.py
+++ b/python/ccxt/async/binance.py
@@ -547,6 +547,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'wapi':
             url += '.html'
         if (api == 'private') or (api == 'wapi'):
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.urlencode(self.extend({'timestamp': nonce}, params))
             signature = None
diff --git a/python/ccxt/async/bit2c.py b/python/ccxt/async/bit2c.py
index 64105bf60b89b..10f75bf691883 100644
--- a/python/ccxt/async/bit2c.py
+++ b/python/ccxt/async/bit2c.py
@@ -161,6 +161,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '.json'
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({'nonce': nonce}, params)
             body = self.urlencode(query)
diff --git a/python/ccxt/async/bitbay.py b/python/ccxt/async/bitbay.py
index 06fc62783e896..15b30f65b6c8b 100644
--- a/python/ccxt/async/bitbay.py
+++ b/python/ccxt/async/bitbay.py
@@ -198,6 +198,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '/' + self.implode_params(path, params) + '.json'
         else:
+            self.check_required_credentials()
             body = self.urlencode(self.extend({
                 'method': path,
                 'moment': self.nonce(),
diff --git a/python/ccxt/async/bitcoincoid.py b/python/ccxt/async/bitcoincoid.py
index 43d8f472d3dd9..6c95bd0f5f40a 100644
--- a/python/ccxt/async/bitcoincoid.py
+++ b/python/ccxt/async/bitcoincoid.py
@@ -159,6 +159,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '/' + self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             body = self.urlencode(self.extend({
                 'method': path,
                 'nonce': self.nonce(),
diff --git a/python/ccxt/async/bitfinex.py b/python/ccxt/async/bitfinex.py
index c4fb0664fdc96..f0e9ef7aceeb2 100644
--- a/python/ccxt/async/bitfinex.py
+++ b/python/ccxt/async/bitfinex.py
@@ -479,6 +479,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 url += suffix
                 request += suffix
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({
                 'nonce': str(nonce),
diff --git a/python/ccxt/async/bitfinex2.py b/python/ccxt/async/bitfinex2.py
index 2ec50e68d9183..e50da3653fd35 100644
--- a/python/ccxt/async/bitfinex2.py
+++ b/python/ccxt/async/bitfinex2.py
@@ -364,6 +364,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.json(query)
             auth = '/api' + '/' + request + nonce + body
diff --git a/python/ccxt/async/bitflyer.py b/python/ccxt/async/bitflyer.py
index abd90ad104486..2a8fd779437d7 100644
--- a/python/ccxt/async/bitflyer.py
+++ b/python/ccxt/async/bitflyer.py
@@ -226,6 +226,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 request += '?' + self.urlencode(params)
         url = self.urls['api'] + request
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.json(params)
             auth = ''.join([nonce, method, request, body])
diff --git a/python/ccxt/async/bithumb.py b/python/ccxt/async/bithumb.py
index d5dbabe18d51b..6280dd2745a03 100644
--- a/python/ccxt/async/bithumb.py
+++ b/python/ccxt/async/bithumb.py
@@ -222,6 +222,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             body = self.urlencode(self.extend({
                 'endpoint': endpoint,
             }, query))
diff --git a/python/ccxt/async/bitlish.py b/python/ccxt/async/bitlish.py
index c586f16b300c2..f59d1a8c71fb1 100644
--- a/python/ccxt/async/bitlish.py
+++ b/python/ccxt/async/bitlish.py
@@ -23,6 +23,10 @@ def describe(self):
                 'www': 'https://bitlish.com',
                 'doc': 'https://bitlish.com/api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -274,6 +278,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 body = self.json(params)
                 headers = {'Content-Type': 'application/json'}
         else:
+            self.check_required_credentials()
             body = self.json(self.extend({'token': self.apiKey}, params))
             headers = {'Content-Type': 'application/json'}
         return {'url': url, 'method': method, 'body': body, 'headers': headers}
diff --git a/python/ccxt/async/bitmarket.py b/python/ccxt/async/bitmarket.py
index 5b7b8034b792a..da4aea614485b 100644
--- a/python/ccxt/async/bitmarket.py
+++ b/python/ccxt/async/bitmarket.py
@@ -270,6 +270,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '/' + self.implode_params(path + '.json', params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({
                 'tonce': nonce,
diff --git a/python/ccxt/async/bitmex.py b/python/ccxt/async/bitmex.py
index eae7741cbb414..3db4b68bd05c8 100644
--- a/python/ccxt/async/bitmex.py
+++ b/python/ccxt/async/bitmex.py
@@ -374,6 +374,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             query += '?' + self.urlencode(params)
         url = self.urls['api'] + query
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             if method == 'POST':
                 if params:
diff --git a/python/ccxt/async/bitso.py b/python/ccxt/async/bitso.py
index 2e6b9ad1b10b2..d2bb76ceb82f6 100644
--- a/python/ccxt/async/bitso.py
+++ b/python/ccxt/async/bitso.py
@@ -221,6 +221,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             request = ''.join([nonce, method, query])
             if params:
diff --git a/python/ccxt/async/bitstamp.py b/python/ccxt/async/bitstamp.py
index 5cafe2a794c94..1c167536478b0 100644
--- a/python/ccxt/async/bitstamp.py
+++ b/python/ccxt/async/bitstamp.py
@@ -2,7 +2,6 @@
 
 from ccxt.async.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class bitstamp (Exchange):
@@ -22,6 +21,11 @@ def describe(self):
                 'www': 'https://www.bitstamp.net',
                 'doc': 'https://www.bitstamp.net/api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -238,8 +242,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.encode(self.hmac(self.encode(auth), self.encode(self.secret)))
diff --git a/python/ccxt/async/bitstamp1.py b/python/ccxt/async/bitstamp1.py
index 0beec90d70d06..13a3effb0e13d 100644
--- a/python/ccxt/async/bitstamp1.py
+++ b/python/ccxt/async/bitstamp1.py
@@ -3,7 +3,6 @@
 from ccxt.async.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
 from ccxt.base.errors import NotSupported
-from ccxt.base.errors import AuthenticationError
 
 
 class bitstamp1 (Exchange):
@@ -22,6 +21,11 @@ def describe(self):
                 'www': 'https://www.bitstamp.net',
                 'doc': 'https://www.bitstamp.net/api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -207,8 +211,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.encode(self.hmac(self.encode(auth), self.encode(self.secret)))
diff --git a/python/ccxt/async/bittrex.py b/python/ccxt/async/bittrex.py
index 6dd5b6054afe0..6a5c1e0eafabf 100644
--- a/python/ccxt/async/bittrex.py
+++ b/python/ccxt/async/bittrex.py
@@ -509,6 +509,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             url += api + '/'
             if ((api == 'account') and(path != 'withdraw')) or (path == 'openorders'):
diff --git a/python/ccxt/async/bl3p.py b/python/ccxt/async/bl3p.py
index e35b89e123f0a..22af55f050469 100644
--- a/python/ccxt/async/bl3p.py
+++ b/python/ccxt/async/bl3p.py
@@ -168,6 +168,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, query))
             secret = base64.b64decode(self.secret)
diff --git a/python/ccxt/async/btcbox.py b/python/ccxt/async/btcbox.py
index 06ac9188fc3df..308fa4a458577 100644
--- a/python/ccxt/async/btcbox.py
+++ b/python/ccxt/async/btcbox.py
@@ -181,6 +181,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             query = self.extend({
                 'key': self.apiKey,
diff --git a/python/ccxt/async/btcchina.py b/python/ccxt/async/btcchina.py
index 6b17483fc33e9..baf6653215b96 100644
--- a/python/ccxt/async/btcchina.py
+++ b/python/ccxt/async/btcchina.py
@@ -3,7 +3,6 @@
 from ccxt.async.base.exchange import Exchange
 import base64
 import hashlib
-from ccxt.base.errors import AuthenticationError
 
 
 class btcchina (Exchange):
@@ -280,10 +279,7 @@ def nonce(self):
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
         url = self.urls['api'][api] + '/' + path
         if api == 'private':
-            if not self.apiKey:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.apiKey` property for authentication')
-            if not self.secret:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.secret` property for authentication')
+            self.check_required_credentials()
             p = []
             if 'params' in params:
                 p = params['params']
diff --git a/python/ccxt/async/btcmarkets.py b/python/ccxt/async/btcmarkets.py
index e4fcea5cf8672..401278b6caf0c 100644
--- a/python/ccxt/async/btcmarkets.py
+++ b/python/ccxt/async/btcmarkets.py
@@ -187,6 +187,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = uri + "\n" + nonce + "\n"
             headers = {
diff --git a/python/ccxt/async/btctradeua.py b/python/ccxt/async/btctradeua.py
index 01885b4244382..258f50af1aee1 100644
--- a/python/ccxt/async/btctradeua.py
+++ b/python/ccxt/async/btctradeua.py
@@ -279,6 +279,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += self.implode_params(path, query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({
                 'out_order_id': nonce,
diff --git a/python/ccxt/async/btcturk.py b/python/ccxt/async/btcturk.py
index 8fa291cef4475..0e2b9c6160f22 100644
--- a/python/ccxt/async/btcturk.py
+++ b/python/ccxt/async/btcturk.py
@@ -202,6 +202,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce().toString
             body = self.urlencode(params)
             secret = self.base64ToString(self.secret)
diff --git a/python/ccxt/async/btcx.py b/python/ccxt/async/btcx.py
index 00ab8a8ef8560..1289d8490fb6f 100644
--- a/python/ccxt/async/btcx.py
+++ b/python/ccxt/async/btcx.py
@@ -138,6 +138,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             url += api
             body = self.urlencode(self.extend({
diff --git a/python/ccxt/async/bter.py b/python/ccxt/async/bter.py
index 909e6f9f5ff50..f2948381f5132 100644
--- a/python/ccxt/async/bter.py
+++ b/python/ccxt/async/bter.py
@@ -247,6 +247,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = {'nonce': nonce}
             body = self.urlencode(self.extend(request, query))
diff --git a/python/ccxt/async/bxinth.py b/python/ccxt/async/bxinth.py
index ad988ee9b013f..0e8c6cd72f9bf 100644
--- a/python/ccxt/async/bxinth.py
+++ b/python/ccxt/async/bxinth.py
@@ -219,6 +219,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if params:
             url += '?' + self.urlencode(params)
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             auth = self.apiKey + str(nonce) + self.secret
             signature = self.hash(self.encode(auth), 'sha256')
diff --git a/python/ccxt/async/ccex.py b/python/ccxt/async/ccex.py
index 91127e2a295ce..2ee25894bacbc 100644
--- a/python/ccxt/async/ccex.py
+++ b/python/ccxt/async/ccex.py
@@ -224,6 +224,7 @@ async def cancel_order(self, id, symbol=None, params={}):
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
         url = self.urls['api'][api]
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             query = self.keysort(self.extend({
                 'a': path,
diff --git a/python/ccxt/async/cex.py b/python/ccxt/async/cex.py
index d9c4b783fb0ea..07c1709ed2cde 100644
--- a/python/ccxt/async/cex.py
+++ b/python/ccxt/async/cex.py
@@ -4,7 +4,6 @@
 import math
 import json
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class cex (Exchange):
@@ -28,6 +27,11 @@ def describe(self):
                 'www': 'https://cex.io',
                 'doc': 'https://cex.io/cex-api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -356,8 +360,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.hmac(self.encode(auth), self.encode(self.secret))
diff --git a/python/ccxt/async/coincheck.py b/python/ccxt/async/coincheck.py
index 7c40e64a36f88..b2f88d8014a8c 100644
--- a/python/ccxt/async/coincheck.py
+++ b/python/ccxt/async/coincheck.py
@@ -190,6 +190,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             if query:
                 body = self.urlencode(self.keysort(query))
diff --git a/python/ccxt/async/coinfloor.py b/python/ccxt/async/coinfloor.py
index 15a59719e324b..9d80d00276daa 100644
--- a/python/ccxt/async/coinfloor.py
+++ b/python/ccxt/async/coinfloor.py
@@ -23,6 +23,11 @@ def describe(self):
                     'https://www.coinfloor.co.uk/api',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -155,6 +160,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, query))
             auth = self.uid + '/' + self.apiKey + ':' + self.password
diff --git a/python/ccxt/async/coingi.py b/python/ccxt/async/coingi.py
index 5eb073466a81f..bbfb8c37a0813 100644
--- a/python/ccxt/async/coingi.py
+++ b/python/ccxt/async/coingi.py
@@ -187,6 +187,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = self.extend({
                 'token': self.apiKey,
diff --git a/python/ccxt/async/coinmarketcap.py b/python/ccxt/async/coinmarketcap.py
index c836b5368539c..6d0630c1b89d3 100644
--- a/python/ccxt/async/coinmarketcap.py
+++ b/python/ccxt/async/coinmarketcap.py
@@ -27,6 +27,10 @@ def describe(self):
                 'www': 'https://coinmarketcap.com',
                 'doc': 'https://coinmarketcap.com/api',
             },
+            'requiredCredentials': {
+                'apiKey': False,
+                'secret': False,
+            },
             'api': {
                 'public': {
                     'get': [
diff --git a/python/ccxt/async/coinmate.py b/python/ccxt/async/coinmate.py
index eccda98c02d28..2a6f429ba60d5 100644
--- a/python/ccxt/async/coinmate.py
+++ b/python/ccxt/async/coinmate.py
@@ -2,7 +2,6 @@
 
 from ccxt.async.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class coinmate (Exchange):
@@ -23,6 +22,11 @@ def describe(self):
                     'https://coinmate.io/developers',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -166,8 +170,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.hmac(self.encode(auth), self.encode(self.secret))
diff --git a/python/ccxt/async/coinsecure.py b/python/ccxt/async/coinsecure.py
index e77245bf74002..978a6931f9e43 100644
--- a/python/ccxt/async/coinsecure.py
+++ b/python/ccxt/async/coinsecure.py
@@ -23,6 +23,10 @@ def describe(self):
                     'https://github.com/coinsecure/plugins',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -252,6 +256,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'] + '/' + self.version + '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             headers = {'Authorization': self.apiKey}
             if query:
                 body = self.json(query)
diff --git a/python/ccxt/async/coinspot.py b/python/ccxt/async/coinspot.py
index 739bf6173d84f..340f5d2a578a2 100644
--- a/python/ccxt/async/coinspot.py
+++ b/python/ccxt/async/coinspot.py
@@ -136,6 +136,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             raise AuthenticationError(self.id + ' requires apiKey for all requests')
         url = self.urls['api'][api] + '/' + path
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.json(self.extend({'nonce': nonce}, params))
             headers = {
diff --git a/python/ccxt/async/cryptopia.py b/python/ccxt/async/cryptopia.py
index 51ce33d7ce48e..d2d7898012a87 100644
--- a/python/ccxt/async/cryptopia.py
+++ b/python/ccxt/async/cryptopia.py
@@ -459,6 +459,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.json(query)
             hash = self.hash(self.encode(body), 'md5', 'base64')
diff --git a/python/ccxt/async/exmo.py b/python/ccxt/async/exmo.py
index 7773ee51845a8..ca47daed681f1 100644
--- a/python/ccxt/async/exmo.py
+++ b/python/ccxt/async/exmo.py
@@ -232,6 +232,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, params))
             headers = {
diff --git a/python/ccxt/async/flowbtc.py b/python/ccxt/async/flowbtc.py
index d3537ce85c7ff..d5262eade2553 100644
--- a/python/ccxt/async/flowbtc.py
+++ b/python/ccxt/async/flowbtc.py
@@ -2,7 +2,6 @@
 
 from ccxt.async.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class flowbtc (Exchange):
@@ -21,6 +20,11 @@ def describe(self):
                 'www': 'https://trader.flowbtc.com',
                 'doc': 'http://www.flowbtc.com.br/api/',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'post': [
@@ -179,8 +183,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 body = self.json(params)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = self.nonce()
             auth = str(nonce) + self.uid + self.apiKey
             signature = self.hmac(self.encode(auth), self.encode(self.secret))
diff --git a/python/ccxt/async/foxbit.py b/python/ccxt/async/foxbit.py
index bff67d9ce7020..45061000ee889 100644
--- a/python/ccxt/async/foxbit.py
+++ b/python/ccxt/async/foxbit.py
@@ -156,6 +156,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             request = self.extend({'MsgType': path}, query)
             body = self.json(request)
diff --git a/python/ccxt/async/fybse.py b/python/ccxt/async/fybse.py
index bb47ffa2da441..9ab1ac7cc45e6 100644
--- a/python/ccxt/async/fybse.py
+++ b/python/ccxt/async/fybse.py
@@ -140,6 +140,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '.json'
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'timestamp': nonce}, params))
             headers = {
diff --git a/python/ccxt/async/gatecoin.py b/python/ccxt/async/gatecoin.py
index 45cd24ab5a415..20cd2f1d5c2d7 100644
--- a/python/ccxt/async/gatecoin.py
+++ b/python/ccxt/async/gatecoin.py
@@ -365,6 +365,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             contentType = '' if (method == 'GET') else 'application/json'
             auth = method + url + contentType + str(nonce)
diff --git a/python/ccxt/async/gdax.py b/python/ccxt/async/gdax.py
index 867cb672eff29..faeb5f391fc69 100644
--- a/python/ccxt/async/gdax.py
+++ b/python/ccxt/async/gdax.py
@@ -48,6 +48,11 @@ def describe(self):
                 'www': 'https://www.gdax.com',
                 'doc': 'https://docs.gdax.com',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'password': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -426,12 +431,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 request += '?' + self.urlencode(query)
         url = self.urls['api'] + request
         if api == 'private':
-            if not self.apiKey:
-                raise AuthenticationError(self.id + ' requires apiKey property for authentication and trading')
-            if not self.secret:
-                raise AuthenticationError(self.id + ' requires secret property for authentication and trading')
-            if not self.password:
-                raise AuthenticationError(self.id + ' requires password property for authentication and trading')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             payload = ''
             if method != 'GET':
diff --git a/python/ccxt/async/gemini.py b/python/ccxt/async/gemini.py
index f3746d74703a5..029fc3319dfa7 100644
--- a/python/ccxt/async/gemini.py
+++ b/python/ccxt/async/gemini.py
@@ -177,6 +177,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = self.extend({
                 'request': url,
diff --git a/python/ccxt/async/hitbtc.py b/python/ccxt/async/hitbtc.py
index 80118eb57ea07..6e758244235be 100644
--- a/python/ccxt/async/hitbtc.py
+++ b/python/ccxt/async/hitbtc.py
@@ -358,6 +358,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             payload = {'nonce': nonce, 'apikey': self.apiKey}
             query = self.extend(payload, query)
diff --git a/python/ccxt/async/hitbtc2.py b/python/ccxt/async/hitbtc2.py
index 924608a32b865..4c6fef20f055a 100644
--- a/python/ccxt/async/hitbtc2.py
+++ b/python/ccxt/async/hitbtc2.py
@@ -464,6 +464,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             url += self.implode_params(path, params)
             if method == 'GET':
                 if query:
diff --git a/python/ccxt/async/huobi.py b/python/ccxt/async/huobi.py
index a88137feb8f28..a508a877a664e 100644
--- a/python/ccxt/async/huobi.py
+++ b/python/ccxt/async/huobi.py
@@ -204,6 +204,7 @@ async def cancel_order(self, id, symbol=None, params={}):
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
         url = self.urls['api']
         if api == 'trade':
+            self.check_required_credentials()
             url += '/api' + self.version
             query = self.keysort(self.extend({
                 'method': path,
diff --git a/python/ccxt/async/huobipro.py b/python/ccxt/async/huobipro.py
index 58056df2439be..fc4d4d9a28dd0 100644
--- a/python/ccxt/async/huobipro.py
+++ b/python/ccxt/async/huobipro.py
@@ -310,6 +310,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url += '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             timestamp = self.YmdHMS(self.milliseconds(), 'T')
             request = self.keysort(self.extend({
                 'SignatureMethod': 'HmacSHA256',
diff --git a/python/ccxt/async/independentreserve.py b/python/ccxt/async/independentreserve.py
index e0927951bbb68..6d92efa3cca75 100644
--- a/python/ccxt/async/independentreserve.py
+++ b/python/ccxt/async/independentreserve.py
@@ -205,6 +205,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             auth = [
                 url,
diff --git a/python/ccxt/async/itbit.py b/python/ccxt/async/itbit.py
index 4191b769fdd67..5cc5d4a7e02ef 100644
--- a/python/ccxt/async/itbit.py
+++ b/python/ccxt/async/itbit.py
@@ -189,6 +189,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             if query:
                 body = self.json(query)
             else:
diff --git a/python/ccxt/async/kraken.py b/python/ccxt/async/kraken.py
index b41ab64bc8bd9..bb07174cf4dde 100644
--- a/python/ccxt/async/kraken.py
+++ b/python/ccxt/async/kraken.py
@@ -543,6 +543,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.urlencode(self.extend({'nonce': nonce}, params))
             auth = self.encode(nonce + body)
diff --git a/python/ccxt/async/lakebtc.py b/python/ccxt/async/lakebtc.py
index d83732971133b..3fba0c71c93a1 100644
--- a/python/ccxt/async/lakebtc.py
+++ b/python/ccxt/async/lakebtc.py
@@ -179,6 +179,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             if params:
                 params = ','.join(params)
diff --git a/python/ccxt/async/liqui.py b/python/ccxt/async/liqui.py
index d4c4846cf6dd0..992e1455ec3e3 100644
--- a/python/ccxt/async/liqui.py
+++ b/python/ccxt/async/liqui.py
@@ -522,6 +522,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'][api]
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({
                 'nonce': nonce,
diff --git a/python/ccxt/async/livecoin.py b/python/ccxt/async/livecoin.py
index 01525082f8f8d..60ce69bdb6d41 100644
--- a/python/ccxt/async/livecoin.py
+++ b/python/ccxt/async/livecoin.py
@@ -221,6 +221,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + query
         if api == 'private':
+            self.check_required_credentials()
             if method == 'POST':
                 body = query
             signature = self.hmac(self.encode(query), self.encode(self.secret), hashlib.sha256)
diff --git a/python/ccxt/async/luno.py b/python/ccxt/async/luno.py
index adad82b6a344f..88edba08c5809 100644
--- a/python/ccxt/async/luno.py
+++ b/python/ccxt/async/luno.py
@@ -224,6 +224,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if query:
             url += '?' + self.urlencode(query)
         if api == 'private':
+            self.check_required_credentials()
             auth = self.encode(self.apiKey + ':' + self.secret)
             auth = base64.b64encode(auth)
             headers = {'Authorization': 'Basic ' + self.decode(auth)}
diff --git a/python/ccxt/async/mercado.py b/python/ccxt/async/mercado.py
index 16b513ef0e79e..4e7ad921ed960 100644
--- a/python/ccxt/async/mercado.py
+++ b/python/ccxt/async/mercado.py
@@ -179,6 +179,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             url += self.version + '/'
             nonce = self.nonce()
             body = self.urlencode(self.extend({
diff --git a/python/ccxt/async/mixcoins.py b/python/ccxt/async/mixcoins.py
index 9cf3b6699e0d3..d0d764a4ddef3 100644
--- a/python/ccxt/async/mixcoins.py
+++ b/python/ccxt/async/mixcoins.py
@@ -145,6 +145,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({
                 'nonce': nonce,
diff --git a/python/ccxt/async/nova.py b/python/ccxt/async/nova.py
index 0706925530844..150610e33bd5d 100644
--- a/python/ccxt/async/nova.py
+++ b/python/ccxt/async/nova.py
@@ -187,6 +187,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             url += '?' + self.urlencode({'nonce': nonce})
             signature = self.hmac(self.encode(url), self.encode(self.secret), hashlib.sha512, 'base64')
diff --git a/python/ccxt/async/okcoinusd.py b/python/ccxt/async/okcoinusd.py
index 177d8f567e3bd..2c085eca3d32a 100644
--- a/python/ccxt/async/okcoinusd.py
+++ b/python/ccxt/async/okcoinusd.py
@@ -494,6 +494,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             url += self.version + '/'
         url += path + self.extension
         if api == 'private':
+            self.check_required_credentials()
             query = self.keysort(self.extend({
                 'api_key': self.apiKey,
             }, params))
diff --git a/python/ccxt/async/paymium.py b/python/ccxt/async/paymium.py
index 033f3f8d2b25f..7efffba2eb769 100644
--- a/python/ccxt/async/paymium.py
+++ b/python/ccxt/async/paymium.py
@@ -172,6 +172,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             body = self.json(params)
             nonce = str(self.nonce())
             auth = nonce + url + body
diff --git a/python/ccxt/async/poloniex.py b/python/ccxt/async/poloniex.py
index 0ef024df13cb8..f5ddc62c5a25f 100644
--- a/python/ccxt/async/poloniex.py
+++ b/python/ccxt/async/poloniex.py
@@ -561,6 +561,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             query['nonce'] = self.nonce()
             body = self.urlencode(query)
             headers = {
diff --git a/python/ccxt/async/qryptos.py b/python/ccxt/async/qryptos.py
index c6bcd94ce1f2f..89bedd0354ec8 100644
--- a/python/ccxt/async/qryptos.py
+++ b/python/ccxt/async/qryptos.py
@@ -225,6 +225,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = {
                 'path': url,
diff --git a/python/ccxt/async/quadrigacx.py b/python/ccxt/async/quadrigacx.py
index 748d28f9e6a1a..6721af406e7b4 100644
--- a/python/ccxt/async/quadrigacx.py
+++ b/python/ccxt/async/quadrigacx.py
@@ -2,7 +2,6 @@
 
 from ccxt.async.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class quadrigacx (Exchange):
@@ -21,6 +20,11 @@ def describe(self):
                 'www': 'https://www.quadrigacx.com',
                 'doc': 'https://www.quadrigacx.com/api_info',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -151,8 +155,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '?' + self.urlencode(params)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = self.nonce()
             request = ''.join([str(nonce), self.uid, self.apiKey])
             signature = self.hmac(self.encode(request), self.encode(self.secret))
diff --git a/python/ccxt/async/southxchange.py b/python/ccxt/async/southxchange.py
index 5c9b9b297de28..f5c7de4efbc45 100644
--- a/python/ccxt/async/southxchange.py
+++ b/python/ccxt/async/southxchange.py
@@ -198,6 +198,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'] + '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({
                 'key': self.apiKey,
diff --git a/python/ccxt/async/therock.py b/python/ccxt/async/therock.py
index fb3ae605bd192..bfc70b094819f 100644
--- a/python/ccxt/async/therock.py
+++ b/python/ccxt/async/therock.py
@@ -214,6 +214,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'] + '/' + self.version + '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + url
             headers = {
diff --git a/python/ccxt/async/vaultoro.py b/python/ccxt/async/vaultoro.py
index 72294f7016499..58e3818fb69f0 100644
--- a/python/ccxt/async/vaultoro.py
+++ b/python/ccxt/async/vaultoro.py
@@ -179,6 +179,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += path
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             url += self.version + '/' + self.implode_params(path, params)
             query = self.extend({
diff --git a/python/ccxt/async/virwox.py b/python/ccxt/async/virwox.py
index f4189ea775dea..c4d3c15a42659 100644
--- a/python/ccxt/async/virwox.py
+++ b/python/ccxt/async/virwox.py
@@ -22,6 +22,12 @@ def describe(self):
                 'www': 'https://www.virwox.com',
                 'doc': 'https://www.virwox.com/developers.php',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+                'login': True,
+                'password': True
+            },
             'api': {
                 'public': {
                     'get': [
@@ -197,6 +203,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'][api]
         auth = {}
         if api == 'private':
+            self.check_required_credentials()
             auth['key'] = self.apiKey
             auth['user'] = self.login
             auth['pass'] = self.password
diff --git a/python/ccxt/async/xbtce.py b/python/ccxt/async/xbtce.py
index 3e4e4741da51d..fa0f536b1b09d 100644
--- a/python/ccxt/async/xbtce.py
+++ b/python/ccxt/async/xbtce.py
@@ -29,6 +29,11 @@ def describe(self):
                     'https://support.xbtce.info/Knowledgebase/Article/View/52/25/xbtce-exchange-api',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -284,7 +289,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if not self.apiKey:
             raise AuthenticationError(self.id + ' requires apiKey for all requests, their public API is always busy')
         if not self.uid:
-            raise AuthenticationError(self.id + ' requires uid property for authentication and trading')
+            raise AuthenticationError(self.id + ' requires uid property for authentication and trading, their public API is always busy')
         url = self.urls['api'] + '/' + self.version
         if api == 'public':
             url += '/' + api
@@ -294,6 +299,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             headers = {'Accept-Encoding': 'gzip, deflate'}
             nonce = str(self.nonce())
             if method == 'POST':
diff --git a/python/ccxt/async/zaif.py b/python/ccxt/async/zaif.py
index c8e7612bbb5ec..cff6d054a897a 100644
--- a/python/ccxt/async/zaif.py
+++ b/python/ccxt/async/zaif.py
@@ -301,6 +301,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         elif api == 'fapi':
             url += 'fapi/' + self.version + '/' + self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             if api == 'ecapi':
                 url += 'ecapi'
             elif api == 'tlapi':
diff --git a/python/ccxt/async/zb.py b/python/ccxt/async/zb.py
index a819db94d0744..6c5e110a4d9a4 100644
--- a/python/ccxt/async/zb.py
+++ b/python/ccxt/async/zb.py
@@ -261,6 +261,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             paramsLength = len(params)  # params should be a string here
             nonce = self.nonce()
             auth = 'method=' + path
diff --git a/python/ccxt/binance.py b/python/ccxt/binance.py
index 5321dc04e13b9..7189586889be6 100644
--- a/python/ccxt/binance.py
+++ b/python/ccxt/binance.py
@@ -547,6 +547,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'wapi':
             url += '.html'
         if (api == 'private') or (api == 'wapi'):
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.urlencode(self.extend({'timestamp': nonce}, params))
             signature = None
diff --git a/python/ccxt/bit2c.py b/python/ccxt/bit2c.py
index d40d6e563399f..56315641d7f4a 100644
--- a/python/ccxt/bit2c.py
+++ b/python/ccxt/bit2c.py
@@ -161,6 +161,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '.json'
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({'nonce': nonce}, params)
             body = self.urlencode(query)
diff --git a/python/ccxt/bitbay.py b/python/ccxt/bitbay.py
index 11b3de4eaeb25..f5d0c6b44790e 100644
--- a/python/ccxt/bitbay.py
+++ b/python/ccxt/bitbay.py
@@ -198,6 +198,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '/' + self.implode_params(path, params) + '.json'
         else:
+            self.check_required_credentials()
             body = self.urlencode(self.extend({
                 'method': path,
                 'moment': self.nonce(),
diff --git a/python/ccxt/bitcoincoid.py b/python/ccxt/bitcoincoid.py
index da3098a78c001..08dbd7cd71c7b 100644
--- a/python/ccxt/bitcoincoid.py
+++ b/python/ccxt/bitcoincoid.py
@@ -159,6 +159,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '/' + self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             body = self.urlencode(self.extend({
                 'method': path,
                 'nonce': self.nonce(),
diff --git a/python/ccxt/bitfinex.py b/python/ccxt/bitfinex.py
index e0c898dc7f864..798180dd211b2 100644
--- a/python/ccxt/bitfinex.py
+++ b/python/ccxt/bitfinex.py
@@ -479,6 +479,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 url += suffix
                 request += suffix
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({
                 'nonce': str(nonce),
diff --git a/python/ccxt/bitfinex2.py b/python/ccxt/bitfinex2.py
index 50a956eb2cfc7..5ec285b8551b2 100644
--- a/python/ccxt/bitfinex2.py
+++ b/python/ccxt/bitfinex2.py
@@ -364,6 +364,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.json(query)
             auth = '/api' + '/' + request + nonce + body
diff --git a/python/ccxt/bitflyer.py b/python/ccxt/bitflyer.py
index 1329c05885f56..9097427b3819c 100644
--- a/python/ccxt/bitflyer.py
+++ b/python/ccxt/bitflyer.py
@@ -226,6 +226,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 request += '?' + self.urlencode(params)
         url = self.urls['api'] + request
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.json(params)
             auth = ''.join([nonce, method, request, body])
diff --git a/python/ccxt/bithumb.py b/python/ccxt/bithumb.py
index a9da98b06bd37..bab4deca1b677 100644
--- a/python/ccxt/bithumb.py
+++ b/python/ccxt/bithumb.py
@@ -222,6 +222,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             body = self.urlencode(self.extend({
                 'endpoint': endpoint,
             }, query))
diff --git a/python/ccxt/bitlish.py b/python/ccxt/bitlish.py
index aecc183f1478d..bc7642b0077c1 100644
--- a/python/ccxt/bitlish.py
+++ b/python/ccxt/bitlish.py
@@ -23,6 +23,10 @@ def describe(self):
                 'www': 'https://bitlish.com',
                 'doc': 'https://bitlish.com/api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -274,6 +278,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 body = self.json(params)
                 headers = {'Content-Type': 'application/json'}
         else:
+            self.check_required_credentials()
             body = self.json(self.extend({'token': self.apiKey}, params))
             headers = {'Content-Type': 'application/json'}
         return {'url': url, 'method': method, 'body': body, 'headers': headers}
diff --git a/python/ccxt/bitmarket.py b/python/ccxt/bitmarket.py
index 3f38aa77e0760..15b31cc2d6d05 100644
--- a/python/ccxt/bitmarket.py
+++ b/python/ccxt/bitmarket.py
@@ -270,6 +270,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '/' + self.implode_params(path + '.json', params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({
                 'tonce': nonce,
diff --git a/python/ccxt/bitmex.py b/python/ccxt/bitmex.py
index 05de758689e4f..b3ff8ce51d41c 100644
--- a/python/ccxt/bitmex.py
+++ b/python/ccxt/bitmex.py
@@ -374,6 +374,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             query += '?' + self.urlencode(params)
         url = self.urls['api'] + query
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             if method == 'POST':
                 if params:
diff --git a/python/ccxt/bitso.py b/python/ccxt/bitso.py
index 066d8e70a12cc..f402767eb9a2f 100644
--- a/python/ccxt/bitso.py
+++ b/python/ccxt/bitso.py
@@ -221,6 +221,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             request = ''.join([nonce, method, query])
             if params:
diff --git a/python/ccxt/bitstamp.py b/python/ccxt/bitstamp.py
index df0955c10cb32..599e37941cadd 100644
--- a/python/ccxt/bitstamp.py
+++ b/python/ccxt/bitstamp.py
@@ -2,7 +2,6 @@
 
 from ccxt.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class bitstamp (Exchange):
@@ -22,6 +21,11 @@ def describe(self):
                 'www': 'https://www.bitstamp.net',
                 'doc': 'https://www.bitstamp.net/api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -238,8 +242,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.encode(self.hmac(self.encode(auth), self.encode(self.secret)))
diff --git a/python/ccxt/bitstamp1.py b/python/ccxt/bitstamp1.py
index 81b7a0a4d2eab..58d20eba4e3aa 100644
--- a/python/ccxt/bitstamp1.py
+++ b/python/ccxt/bitstamp1.py
@@ -3,7 +3,6 @@
 from ccxt.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
 from ccxt.base.errors import NotSupported
-from ccxt.base.errors import AuthenticationError
 
 
 class bitstamp1 (Exchange):
@@ -22,6 +21,11 @@ def describe(self):
                 'www': 'https://www.bitstamp.net',
                 'doc': 'https://www.bitstamp.net/api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -207,8 +211,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.encode(self.hmac(self.encode(auth), self.encode(self.secret)))
diff --git a/python/ccxt/bittrex.py b/python/ccxt/bittrex.py
index 8dfd44e803b5a..de41f68ebcc44 100644
--- a/python/ccxt/bittrex.py
+++ b/python/ccxt/bittrex.py
@@ -509,6 +509,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             url += api + '/'
             if ((api == 'account') and(path != 'withdraw')) or (path == 'openorders'):
diff --git a/python/ccxt/bl3p.py b/python/ccxt/bl3p.py
index e67f04ac22caa..8ae80e69c655d 100644
--- a/python/ccxt/bl3p.py
+++ b/python/ccxt/bl3p.py
@@ -168,6 +168,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, query))
             secret = base64.b64decode(self.secret)
diff --git a/python/ccxt/btcbox.py b/python/ccxt/btcbox.py
index 55a3bc42f9162..72b5423ee480c 100644
--- a/python/ccxt/btcbox.py
+++ b/python/ccxt/btcbox.py
@@ -181,6 +181,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             query = self.extend({
                 'key': self.apiKey,
diff --git a/python/ccxt/btcchina.py b/python/ccxt/btcchina.py
index 613eafe66ef46..aba93f323db5b 100644
--- a/python/ccxt/btcchina.py
+++ b/python/ccxt/btcchina.py
@@ -3,7 +3,6 @@
 from ccxt.base.exchange import Exchange
 import base64
 import hashlib
-from ccxt.base.errors import AuthenticationError
 
 
 class btcchina (Exchange):
@@ -280,10 +279,7 @@ def nonce(self):
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
         url = self.urls['api'][api] + '/' + path
         if api == 'private':
-            if not self.apiKey:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.apiKey` property for authentication')
-            if not self.secret:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.secret` property for authentication')
+            self.check_required_credentials()
             p = []
             if 'params' in params:
                 p = params['params']
diff --git a/python/ccxt/btcmarkets.py b/python/ccxt/btcmarkets.py
index 06f11c5908f2d..897fd2792ec67 100644
--- a/python/ccxt/btcmarkets.py
+++ b/python/ccxt/btcmarkets.py
@@ -187,6 +187,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = uri + "\n" + nonce + "\n"
             headers = {
diff --git a/python/ccxt/btctradeua.py b/python/ccxt/btctradeua.py
index 0c04ebacd2271..21f608ff56f41 100644
--- a/python/ccxt/btctradeua.py
+++ b/python/ccxt/btctradeua.py
@@ -279,6 +279,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += self.implode_params(path, query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({
                 'out_order_id': nonce,
diff --git a/python/ccxt/btcturk.py b/python/ccxt/btcturk.py
index f8aab61bbe76a..f5d08f4a0d553 100644
--- a/python/ccxt/btcturk.py
+++ b/python/ccxt/btcturk.py
@@ -202,6 +202,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce().toString
             body = self.urlencode(params)
             secret = self.base64ToString(self.secret)
diff --git a/python/ccxt/btcx.py b/python/ccxt/btcx.py
index e44e39530fc20..f1c317a4ce92d 100644
--- a/python/ccxt/btcx.py
+++ b/python/ccxt/btcx.py
@@ -138,6 +138,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             url += api
             body = self.urlencode(self.extend({
diff --git a/python/ccxt/bter.py b/python/ccxt/bter.py
index bf1088b6855e0..dc6bfdb8f1a60 100644
--- a/python/ccxt/bter.py
+++ b/python/ccxt/bter.py
@@ -247,6 +247,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = {'nonce': nonce}
             body = self.urlencode(self.extend(request, query))
diff --git a/python/ccxt/bxinth.py b/python/ccxt/bxinth.py
index 2f77e8e86c9fd..5587c05a8af44 100644
--- a/python/ccxt/bxinth.py
+++ b/python/ccxt/bxinth.py
@@ -219,6 +219,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if params:
             url += '?' + self.urlencode(params)
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             auth = self.apiKey + str(nonce) + self.secret
             signature = self.hash(self.encode(auth), 'sha256')
diff --git a/python/ccxt/ccex.py b/python/ccxt/ccex.py
index 83b04065d0eb3..c5d6c245dcccb 100644
--- a/python/ccxt/ccex.py
+++ b/python/ccxt/ccex.py
@@ -224,6 +224,7 @@ def cancel_order(self, id, symbol=None, params={}):
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
         url = self.urls['api'][api]
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             query = self.keysort(self.extend({
                 'a': path,
diff --git a/python/ccxt/cex.py b/python/ccxt/cex.py
index 5e4d8167a9daf..9e651a586914f 100644
--- a/python/ccxt/cex.py
+++ b/python/ccxt/cex.py
@@ -4,7 +4,6 @@
 import math
 import json
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class cex (Exchange):
@@ -28,6 +27,11 @@ def describe(self):
                 'www': 'https://cex.io',
                 'doc': 'https://cex.io/cex-api',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -356,8 +360,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.hmac(self.encode(auth), self.encode(self.secret))
diff --git a/python/ccxt/coincheck.py b/python/ccxt/coincheck.py
index 0d49653ce08d2..a3487ee73e2e8 100644
--- a/python/ccxt/coincheck.py
+++ b/python/ccxt/coincheck.py
@@ -190,6 +190,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             if query:
                 body = self.urlencode(self.keysort(query))
diff --git a/python/ccxt/coinfloor.py b/python/ccxt/coinfloor.py
index 84654d1176d53..e1be4ff4772ba 100644
--- a/python/ccxt/coinfloor.py
+++ b/python/ccxt/coinfloor.py
@@ -23,6 +23,11 @@ def describe(self):
                     'https://www.coinfloor.co.uk/api',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -155,6 +160,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, query))
             auth = self.uid + '/' + self.apiKey + ':' + self.password
diff --git a/python/ccxt/coingi.py b/python/ccxt/coingi.py
index acd7731be60da..13697e484f11b 100644
--- a/python/ccxt/coingi.py
+++ b/python/ccxt/coingi.py
@@ -187,6 +187,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = self.extend({
                 'token': self.apiKey,
diff --git a/python/ccxt/coinmarketcap.py b/python/ccxt/coinmarketcap.py
index d0a178ce3d80a..4af2f5cbc6123 100644
--- a/python/ccxt/coinmarketcap.py
+++ b/python/ccxt/coinmarketcap.py
@@ -27,6 +27,10 @@ def describe(self):
                 'www': 'https://coinmarketcap.com',
                 'doc': 'https://coinmarketcap.com/api',
             },
+            'requiredCredentials': {
+                'apiKey': False,
+                'secret': False,
+            },
             'api': {
                 'public': {
                     'get': [
diff --git a/python/ccxt/coinmate.py b/python/ccxt/coinmate.py
index b9a3f925e81b7..d746aac061ec6 100644
--- a/python/ccxt/coinmate.py
+++ b/python/ccxt/coinmate.py
@@ -2,7 +2,6 @@
 
 from ccxt.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class coinmate (Exchange):
@@ -23,6 +22,11 @@ def describe(self):
                     'https://coinmate.io/developers',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -166,8 +170,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + self.uid + self.apiKey
             signature = self.hmac(self.encode(auth), self.encode(self.secret))
diff --git a/python/ccxt/coinsecure.py b/python/ccxt/coinsecure.py
index 94e29eeb56a54..851d875766d77 100644
--- a/python/ccxt/coinsecure.py
+++ b/python/ccxt/coinsecure.py
@@ -23,6 +23,10 @@ def describe(self):
                     'https://github.com/coinsecure/plugins',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -252,6 +256,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'] + '/' + self.version + '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             headers = {'Authorization': self.apiKey}
             if query:
                 body = self.json(query)
diff --git a/python/ccxt/coinspot.py b/python/ccxt/coinspot.py
index ad10d2c4f20cc..c9379d6c61f47 100644
--- a/python/ccxt/coinspot.py
+++ b/python/ccxt/coinspot.py
@@ -136,6 +136,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             raise AuthenticationError(self.id + ' requires apiKey for all requests')
         url = self.urls['api'][api] + '/' + path
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.json(self.extend({'nonce': nonce}, params))
             headers = {
diff --git a/python/ccxt/cryptopia.py b/python/ccxt/cryptopia.py
index 47dac73985049..3e4cfc5d98632 100644
--- a/python/ccxt/cryptopia.py
+++ b/python/ccxt/cryptopia.py
@@ -459,6 +459,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.json(query)
             hash = self.hash(self.encode(body), 'md5', 'base64')
diff --git a/python/ccxt/exmo.py b/python/ccxt/exmo.py
index d7d2d0cb92d8f..952ea81fd1e55 100644
--- a/python/ccxt/exmo.py
+++ b/python/ccxt/exmo.py
@@ -232,6 +232,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'nonce': nonce}, params))
             headers = {
diff --git a/python/ccxt/flowbtc.py b/python/ccxt/flowbtc.py
index 200c83e304b69..2153a8b8e2852 100644
--- a/python/ccxt/flowbtc.py
+++ b/python/ccxt/flowbtc.py
@@ -2,7 +2,6 @@
 
 from ccxt.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class flowbtc (Exchange):
@@ -21,6 +20,11 @@ def describe(self):
                 'www': 'https://trader.flowbtc.com',
                 'doc': 'http://www.flowbtc.com.br/api/',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'post': [
@@ -179,8 +183,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 body = self.json(params)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = self.nonce()
             auth = str(nonce) + self.uid + self.apiKey
             signature = self.hmac(self.encode(auth), self.encode(self.secret))
diff --git a/python/ccxt/foxbit.py b/python/ccxt/foxbit.py
index ffce8b964c17d..e3e8b5a0dce07 100644
--- a/python/ccxt/foxbit.py
+++ b/python/ccxt/foxbit.py
@@ -156,6 +156,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             request = self.extend({'MsgType': path}, query)
             body = self.json(request)
diff --git a/python/ccxt/fybse.py b/python/ccxt/fybse.py
index d45bac696fad1..3c88fec5ff731 100644
--- a/python/ccxt/fybse.py
+++ b/python/ccxt/fybse.py
@@ -140,6 +140,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '.json'
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({'timestamp': nonce}, params))
             headers = {
diff --git a/python/ccxt/gatecoin.py b/python/ccxt/gatecoin.py
index d823239b413bd..5219888afffc7 100644
--- a/python/ccxt/gatecoin.py
+++ b/python/ccxt/gatecoin.py
@@ -365,6 +365,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             contentType = '' if (method == 'GET') else 'application/json'
             auth = method + url + contentType + str(nonce)
diff --git a/python/ccxt/gdax.py b/python/ccxt/gdax.py
index 69c81db18007b..0372920539a46 100644
--- a/python/ccxt/gdax.py
+++ b/python/ccxt/gdax.py
@@ -48,6 +48,11 @@ def describe(self):
                 'www': 'https://www.gdax.com',
                 'doc': 'https://docs.gdax.com',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'password': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -426,12 +431,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
                 request += '?' + self.urlencode(query)
         url = self.urls['api'] + request
         if api == 'private':
-            if not self.apiKey:
-                raise AuthenticationError(self.id + ' requires apiKey property for authentication and trading')
-            if not self.secret:
-                raise AuthenticationError(self.id + ' requires secret property for authentication and trading')
-            if not self.password:
-                raise AuthenticationError(self.id + ' requires password property for authentication and trading')
+            self.check_required_credentials()
             nonce = str(self.nonce())
             payload = ''
             if method != 'GET':
diff --git a/python/ccxt/gemini.py b/python/ccxt/gemini.py
index ca9500f51e751..a0d9b617e9cf1 100644
--- a/python/ccxt/gemini.py
+++ b/python/ccxt/gemini.py
@@ -177,6 +177,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = self.extend({
                 'request': url,
diff --git a/python/ccxt/hitbtc.py b/python/ccxt/hitbtc.py
index 73eba6f56d46d..722ce4cf11106 100644
--- a/python/ccxt/hitbtc.py
+++ b/python/ccxt/hitbtc.py
@@ -358,6 +358,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             payload = {'nonce': nonce, 'apikey': self.apiKey}
             query = self.extend(payload, query)
diff --git a/python/ccxt/hitbtc2.py b/python/ccxt/hitbtc2.py
index 1e176905ee4b5..dceb3c388e64d 100644
--- a/python/ccxt/hitbtc2.py
+++ b/python/ccxt/hitbtc2.py
@@ -464,6 +464,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             url += self.implode_params(path, params)
             if method == 'GET':
                 if query:
diff --git a/python/ccxt/huobi.py b/python/ccxt/huobi.py
index 8b6d45227cbbf..20825c650ea6c 100644
--- a/python/ccxt/huobi.py
+++ b/python/ccxt/huobi.py
@@ -204,6 +204,7 @@ def cancel_order(self, id, symbol=None, params={}):
     def sign(self, path, api='public', method='GET', params={}, headers=None, body=None):
         url = self.urls['api']
         if api == 'trade':
+            self.check_required_credentials()
             url += '/api' + self.version
             query = self.keysort(self.extend({
                 'method': path,
diff --git a/python/ccxt/huobipro.py b/python/ccxt/huobipro.py
index eab4ec2dba41a..bf70a3c957f99 100644
--- a/python/ccxt/huobipro.py
+++ b/python/ccxt/huobipro.py
@@ -310,6 +310,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url += '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             timestamp = self.YmdHMS(self.milliseconds(), 'T')
             request = self.keysort(self.extend({
                 'SignatureMethod': 'HmacSHA256',
diff --git a/python/ccxt/independentreserve.py b/python/ccxt/independentreserve.py
index e730d36fe215b..cbbf50ec70239 100644
--- a/python/ccxt/independentreserve.py
+++ b/python/ccxt/independentreserve.py
@@ -205,6 +205,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             auth = [
                 url,
diff --git a/python/ccxt/itbit.py b/python/ccxt/itbit.py
index 03db95f2e667c..a2a63bae8d64a 100644
--- a/python/ccxt/itbit.py
+++ b/python/ccxt/itbit.py
@@ -189,6 +189,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             if query:
                 body = self.json(query)
             else:
diff --git a/python/ccxt/kraken.py b/python/ccxt/kraken.py
index 1ce72948a407d..0b933e54ace84 100644
--- a/python/ccxt/kraken.py
+++ b/python/ccxt/kraken.py
@@ -543,6 +543,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             body = self.urlencode(self.extend({'nonce': nonce}, params))
             auth = self.encode(nonce + body)
diff --git a/python/ccxt/lakebtc.py b/python/ccxt/lakebtc.py
index 4e14198809590..07197ef0892d8 100644
--- a/python/ccxt/lakebtc.py
+++ b/python/ccxt/lakebtc.py
@@ -179,6 +179,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             if params:
                 params = ','.join(params)
diff --git a/python/ccxt/liqui.py b/python/ccxt/liqui.py
index f84decc0f8505..8b58f2eba62af 100644
--- a/python/ccxt/liqui.py
+++ b/python/ccxt/liqui.py
@@ -522,6 +522,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'][api]
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({
                 'nonce': nonce,
diff --git a/python/ccxt/livecoin.py b/python/ccxt/livecoin.py
index afe4a91ec736e..51d46e6864a5e 100644
--- a/python/ccxt/livecoin.py
+++ b/python/ccxt/livecoin.py
@@ -221,6 +221,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + query
         if api == 'private':
+            self.check_required_credentials()
             if method == 'POST':
                 body = query
             signature = self.hmac(self.encode(query), self.encode(self.secret), hashlib.sha256)
diff --git a/python/ccxt/luno.py b/python/ccxt/luno.py
index 031ee5c45aa44..e08eb5a6f7a98 100644
--- a/python/ccxt/luno.py
+++ b/python/ccxt/luno.py
@@ -224,6 +224,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if query:
             url += '?' + self.urlencode(query)
         if api == 'private':
+            self.check_required_credentials()
             auth = self.encode(self.apiKey + ':' + self.secret)
             auth = base64.b64encode(auth)
             headers = {'Authorization': 'Basic ' + self.decode(auth)}
diff --git a/python/ccxt/mercado.py b/python/ccxt/mercado.py
index 3d84658ade36d..48850311f267c 100644
--- a/python/ccxt/mercado.py
+++ b/python/ccxt/mercado.py
@@ -179,6 +179,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             url += self.version + '/'
             nonce = self.nonce()
             body = self.urlencode(self.extend({
diff --git a/python/ccxt/mixcoins.py b/python/ccxt/mixcoins.py
index 67b1c95d029e8..d57cf4173d5aa 100644
--- a/python/ccxt/mixcoins.py
+++ b/python/ccxt/mixcoins.py
@@ -145,6 +145,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             body = self.urlencode(self.extend({
                 'nonce': nonce,
diff --git a/python/ccxt/nova.py b/python/ccxt/nova.py
index 3d785a2eb5aca..4a02614c8a734 100644
--- a/python/ccxt/nova.py
+++ b/python/ccxt/nova.py
@@ -187,6 +187,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = str(self.nonce())
             url += '?' + self.urlencode({'nonce': nonce})
             signature = self.hmac(self.encode(url), self.encode(self.secret), hashlib.sha512, 'base64')
diff --git a/python/ccxt/okcoinusd.py b/python/ccxt/okcoinusd.py
index 9627d9862d11d..00649816a0136 100644
--- a/python/ccxt/okcoinusd.py
+++ b/python/ccxt/okcoinusd.py
@@ -494,6 +494,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             url += self.version + '/'
         url += path + self.extension
         if api == 'private':
+            self.check_required_credentials()
             query = self.keysort(self.extend({
                 'api_key': self.apiKey,
             }, params))
diff --git a/python/ccxt/paymium.py b/python/ccxt/paymium.py
index 00d2edc3d6e39..471facb5267c7 100644
--- a/python/ccxt/paymium.py
+++ b/python/ccxt/paymium.py
@@ -172,6 +172,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             body = self.json(params)
             nonce = str(self.nonce())
             auth = nonce + url + body
diff --git a/python/ccxt/poloniex.py b/python/ccxt/poloniex.py
index 51c56d6a38383..e2841f38b3853 100644
--- a/python/ccxt/poloniex.py
+++ b/python/ccxt/poloniex.py
@@ -561,6 +561,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             query['nonce'] = self.nonce()
             body = self.urlencode(query)
             headers = {
diff --git a/python/ccxt/qryptos.py b/python/ccxt/qryptos.py
index 5e0f6a58974df..a8dccd2f312ad 100644
--- a/python/ccxt/qryptos.py
+++ b/python/ccxt/qryptos.py
@@ -225,6 +225,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             request = {
                 'path': url,
diff --git a/python/ccxt/quadrigacx.py b/python/ccxt/quadrigacx.py
index 1eff650cde222..8647e566c1c2f 100644
--- a/python/ccxt/quadrigacx.py
+++ b/python/ccxt/quadrigacx.py
@@ -2,7 +2,6 @@
 
 from ccxt.base.exchange import Exchange
 from ccxt.base.errors import ExchangeError
-from ccxt.base.errors import AuthenticationError
 
 
 class quadrigacx (Exchange):
@@ -21,6 +20,11 @@ def describe(self):
                 'www': 'https://www.quadrigacx.com',
                 'doc': 'https://www.quadrigacx.com/api_info',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -151,8 +155,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += '?' + self.urlencode(params)
         else:
-            if not self.uid:
-                raise AuthenticationError(self.id + ' requires `' + self.id + '.uid` property for authentication')
+            self.check_required_credentials()
             nonce = self.nonce()
             request = ''.join([str(nonce), self.uid, self.apiKey])
             signature = self.hmac(self.encode(request), self.encode(self.secret))
diff --git a/python/ccxt/southxchange.py b/python/ccxt/southxchange.py
index 4ffd0a12a91be..8d31b44fcd0a8 100644
--- a/python/ccxt/southxchange.py
+++ b/python/ccxt/southxchange.py
@@ -198,6 +198,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'] + '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             nonce = self.nonce()
             query = self.extend({
                 'key': self.apiKey,
diff --git a/python/ccxt/therock.py b/python/ccxt/therock.py
index bb3a4f6efac0a..1aa2cfb7f62eb 100644
--- a/python/ccxt/therock.py
+++ b/python/ccxt/therock.py
@@ -214,6 +214,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'] + '/' + self.version + '/' + self.implode_params(path, params)
         query = self.omit(params, self.extract_params(path))
         if api == 'private':
+            self.check_required_credentials()
             nonce = str(self.nonce())
             auth = nonce + url
             headers = {
diff --git a/python/ccxt/vaultoro.py b/python/ccxt/vaultoro.py
index 1b72f5c0a00eb..348ca472cb6a5 100644
--- a/python/ccxt/vaultoro.py
+++ b/python/ccxt/vaultoro.py
@@ -179,6 +179,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if api == 'public':
             url += path
         else:
+            self.check_required_credentials()
             nonce = self.nonce()
             url += self.version + '/' + self.implode_params(path, params)
             query = self.extend({
diff --git a/python/ccxt/virwox.py b/python/ccxt/virwox.py
index fb1d6bb36f451..75406bc9e6245 100644
--- a/python/ccxt/virwox.py
+++ b/python/ccxt/virwox.py
@@ -22,6 +22,12 @@ def describe(self):
                 'www': 'https://www.virwox.com',
                 'doc': 'https://www.virwox.com/developers.php',
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': False,
+                'login': True,
+                'password': True
+            },
             'api': {
                 'public': {
                     'get': [
@@ -197,6 +203,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         url = self.urls['api'][api]
         auth = {}
         if api == 'private':
+            self.check_required_credentials()
             auth['key'] = self.apiKey
             auth['user'] = self.login
             auth['pass'] = self.password
diff --git a/python/ccxt/xbtce.py b/python/ccxt/xbtce.py
index d09cfc39edb91..a63a0c37a7e0b 100644
--- a/python/ccxt/xbtce.py
+++ b/python/ccxt/xbtce.py
@@ -29,6 +29,11 @@ def describe(self):
                     'https://support.xbtce.info/Knowledgebase/Article/View/52/25/xbtce-exchange-api',
                 ],
             },
+            'requiredCredentials': {
+                'apiKey': True,
+                'secret': True,
+                'uid': True,
+            },
             'api': {
                 'public': {
                     'get': [
@@ -284,7 +289,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         if not self.apiKey:
             raise AuthenticationError(self.id + ' requires apiKey for all requests, their public API is always busy')
         if not self.uid:
-            raise AuthenticationError(self.id + ' requires uid property for authentication and trading')
+            raise AuthenticationError(self.id + ' requires uid property for authentication and trading, their public API is always busy')
         url = self.urls['api'] + '/' + self.version
         if api == 'public':
             url += '/' + api
@@ -294,6 +299,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if query:
                 url += '?' + self.urlencode(query)
         else:
+            self.check_required_credentials()
             headers = {'Accept-Encoding': 'gzip, deflate'}
             nonce = str(self.nonce())
             if method == 'POST':
diff --git a/python/ccxt/zaif.py b/python/ccxt/zaif.py
index 5a8f92de314af..34f988fdb4e5d 100644
--- a/python/ccxt/zaif.py
+++ b/python/ccxt/zaif.py
@@ -301,6 +301,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
         elif api == 'fapi':
             url += 'fapi/' + self.version + '/' + self.implode_params(path, params)
         else:
+            self.check_required_credentials()
             if api == 'ecapi':
                 url += 'ecapi'
             elif api == 'tlapi':
diff --git a/python/ccxt/zb.py b/python/ccxt/zb.py
index 1131d0cacc01b..76d0e9b495446 100644
--- a/python/ccxt/zb.py
+++ b/python/ccxt/zb.py
@@ -261,6 +261,7 @@ def sign(self, path, api='public', method='GET', params={}, headers=None, body=N
             if params:
                 url += '?' + self.urlencode(params)
         else:
+            self.check_required_credentials()
             paramsLength = len(params)  # params should be a string here
             nonce = self.nonce()
             auth = 'method=' + path
diff --git a/python/test-bitfinex.py b/python/test-bitfinex.py
deleted file mode 100644
index 0f137c086a8bb..0000000000000
--- a/python/test-bitfinex.py
+++ /dev/null
@@ -1,13 +0,0 @@
-import ccxt
-import time
-
-bitfinex = ccxt.bitfinex({
-    "apiKey": "VM9UCkrumj7VRMeRwRdTDxNudfaVLcknvbSVCsbSNTH",
-    "secret": "ZqEtFicQAem6p1hmfayhJynulPG2ic7vhNRG9tJwuk0",
-    "verbose": True,
-})
-
-print(bitfinex.fetch_balance())
-time.sleep(5)
-print(bitfinex.symbols)
-print(bitfinex.create_order('BTC/USD', 'limit', 'buy', '0.01', '5500'))