Switch to libsecp256k1-based validation for ECDSA

doc/release-notes.md

@@ -0,0 +1,20 @@
+(note: this is a temporary file, to be added-to by anybody, and moved to
+release-notes at release time)
+
+Notable changes
+===============
+
+Signature validation using libsecp256k1
+---------------------------------------
+
+ECDSA signatures inside Zcash transactions now use validation using
+[https://github.com/bitcoin/secp256k1](libsecp256k1) instead of OpenSSL.
+
+Depending on the platform, this means a significant speedup for raw signature
+validation speed. The advantage is largest on x86_64, where validation is over
+five times faster. In practice, this translates to a raw reindexing and new
+block validation times that are less than half of what it was before.
+
+Libsecp256k1 has undergone very extensive testing and validation upstream.
+
+A side effect of this change is that libconsensus no longer depends on OpenSSL.

src/Makefile.am

@@ -124,9 +124,7 @@ BITCOIN_CORE_H = \
   consensus/validation.h \
   core_io.h \
   core_memusage.h \
-  eccryptoverify.h \
   deprecation.h \
-  ecwrapper.h \
   hash.h \
   httprpc.h \
   httpserver.h \
@@ -326,8 +324,6 @@ libbitcoin_common_a_SOURCES = \
   compressor.cpp \
   core_read.cpp \
   core_write.cpp \
-  eccryptoverify.cpp \
-  ecwrapper.cpp \
   hash.cpp \
   key.cpp \
   keystore.cpp \
@@ -505,8 +501,6 @@ libzcashconsensus_la_SOURCES = \
   crypto/sha1.cpp \
   crypto/sha256.cpp \
   crypto/sha512.cpp \
-  eccryptoverify.cpp \
-  ecwrapper.cpp \
   hash.cpp \
   primitives/transaction.cpp \
   pubkey.cpp \
@@ -521,8 +515,8 @@ if GLIBC_BACK_COMPAT
 endif
 
 libzcashconsensus_la_LDFLAGS = -no-undefined $(RELDFLAGS)
-libzcashconsensus_la_LIBADD = $(CRYPTO_LIBS)
-libzcashconsensus_la_CPPFLAGS = $(CRYPTO_CFLAGS) -I$(builddir)/obj -DBUILD_BITCOIN_INTERNAL
+libzcashconsensus_la_LIBADD = $(LIBSECP256K1)
+libzcashconsensus_la_CPPFLAGS = -I$(builddir)/obj -I$(srcdir)/secp256k1/include -DBUILD_BITCOIN_INTERNAL
 
 endif
 #

src/bitcoin-tx.cpp

@@ -445,9 +445,15 @@ static void MutateTxSign(CMutableTransaction& tx, const string& flagStr)
 
 class Secp256k1Init
 {
+    ECCVerifyHandle globalVerifyHandle;
+
 public:
-    Secp256k1Init() { ECC_Start(); }
-    ~Secp256k1Init() { ECC_Stop(); }
+    Secp256k1Init() {
+        ECC_Start();
+    }
+    ~Secp256k1Init() {
+        ECC_Stop();
+    }
 };
 
 static void MutateTx(CMutableTransaction& tx, const string& command,