Add some documentation and tiny fixes

README.md

@@ -7,8 +7,8 @@ http://fish.secure.la/
 
 This version uses a separate blowfish library to allow usage of keys with a length of up to 72 bytes.
 
-v0.10
-----
+Secured data
+------------
 Can use [weechat secured data][weechat-secure] to store keys. To encrypt keys:
 ```
 /secure set fish *********
@@ -25,10 +25,27 @@ To return to storing in plain text:
 /set fish.secure.key ""
 ```
 
+CBC
+---
+This supports ECB and CBC modes for encryption. To indicate CBC mode you need to prefix a key with `cbc:`
+
+The default for DH1080 key exchange is to indicate that CBC is supported. If you deal with people that have incompatible installations of DH1080 you can force the *old* style of DH1080 key exchange messages by prodiving the argument `-ecb` to the blowkey exchange command.
+
+Normal key exchange the same way [flakes/mirc_fish_10][flakes-fish10] does it, indicating CBC support with a suffixed `CBC` tag:
+```
+/blowkey exchange
+```
+
+Old-style blowkey exchange with no indication of CBC support:
+```
+/blowkey exchange -ecb
+```
+
 Install
 ------
-Run `make` then if you store your weechat scripts in the standard location `~/.weechat/python`, just run `make install`.
+Run `make` to compile the custom blowfish library. If you store your weechat scripts in the standard location `~/.weechat/python`, just run `make install`.
 
 Otherwise copy the resulting `fish.py` and `weechat.so` to your weechat installations `python` directory.
 
 [weechat-secure]: http://dev.weechat.org/post/2013/08/04/Secured-data
+[flakes-fish10]: https://github.com/flakes/mirc_fish_10

fish.py

@@ -86,7 +86,7 @@
 try:
     import Crypto.Cipher.Blowfish
 except:
-    print("PyCryptodome must be installed to use fish")
+    print("PyCryptodome or PyCrypto must be installed to use fish")
     import_ok = False
 
 try:
@@ -254,13 +254,10 @@ def __init__(self, key):
         if key[0:4] == "cbc:":
             self.mode = Blowfish.MODE_CBC
             key = key[4:]
+            keylimit = 56
         else:
             self.mode = Blowfish.MODE_ECB
-
-        if self.mode == Blowfish.MODE_ECB:
             keylimit = 72
-        else:
-            keylimit = 56
 
         if len(key) > keylimit:
             key = key[:keylimit]
@@ -1009,6 +1006,12 @@ def fish_cmd_blowkey(data, buffer, args):
     else:
         server_name = weechat.buffer_get_string(buffer, "localvar_server")
 
+    if argv[0] == "exchange":
+        cbc_mode = True
+        if len(argv) >= 2 and argv[1] == "-ecb":
+            cbc_mode = False
+            del argv[1]
+
     buffer_type = weechat.buffer_get_string(buffer, "localvar_type")
     # if no target user has been specified grab the one from the buffer if it is private
     if argv[0] == "exchange" and len(argv) == 1 and buffer_type == "private":
@@ -1062,8 +1065,9 @@ def fish_cmd_blowkey(data, buffer, args):
         if server_name == "":
             return weechat.WEECHAT_RC_ERROR
 
-        weechat.prnt(buffer, "Initiating DH1080 Exchange with %s" % target)
-        fish_DH1080ctx[targetl] = DH1080Ctx(cbc=True)
+        cbc_msg = "CBC" if cbc_mode else "ECB"
+        weechat.prnt(buffer, "Initiating %s DH1080 Exchange with %s" % (cbc_msg, target))
+        fish_DH1080ctx[targetl] = DH1080Ctx(cbc=cbc_mode)
         msg = dh1080_pack(fish_DH1080ctx[targetl])
         weechat.command(buffer, "/mute -all notice -server %s %s %s" % (server_name, target_user, msg))
 
@@ -1273,7 +1277,7 @@ def fish_msg_wo_marker(msg):
     weechat.hook_command("blowkey", "Manage FiSH keys",
             "[list] | [genkey] |set [-server <server>] [<target>] <key> "
             "| remove [-server <server>] <target> "
-            "| exchange [-server <server>] [<nick>]",
+            "| exchange [-server <server>] [-ecb] [<nick>]",
             "Add, change or remove key for target or perform DH1080\n"
             "keyexchange with <nick>.\n"
             "Target can be a channel or a nick.\n"
@@ -1287,12 +1291,13 @@ def fish_msg_wo_marker(msg):
             "List all keys:             /blowkey\n\n"
             "\n** stores keys in plaintext by default **\n\n"
             "DH1080:                    /blowkey exchange nick\n"
+            "DH1080 (no CBC):           /blowkey exchange -ecb nick\n"
             "\nPlease read the source for a note about DH1080 key exchange\n",
             "list"
             "|| genkey"
             "|| set %(irc_channel)|%(nicks)|-server %(irc_servers) %- "
             "|| remove %(irc_channel)|%(nicks)|-server %(irc_servers) %- "
-            "|| exchange %(nick)|-server %(irc_servers) %-",
+            "|| exchange %(nick)|-server %(irc_servers) %-|-ecb",
             "fish_cmd_blowkey", "")
 
     fish_config_init()