Use libsecp256k1's RFC6979 implementation

src/Makefile.am

@@ -209,14 +209,12 @@ crypto_libbitcoin_crypto_a_SOURCES = \
   crypto/sha256.cpp \
   crypto/sha512.cpp \
   crypto/hmac_sha256.cpp \
-  crypto/rfc6979_hmac_sha256.cpp \
   crypto/hmac_sha512.cpp \
   crypto/ripemd160.cpp \
   crypto/common.h \
   crypto/sha256.h \
   crypto/sha512.h \
   crypto/hmac_sha256.h \
-  crypto/rfc6979_hmac_sha256.h \
   crypto/hmac_sha512.h \
   crypto/sha1.h \
   crypto/ripemd160.h

src/crypto/rfc6979_hmac_sha256.cpp

@@ -1,47 +0,0 @@
-// Copyright (c) 2014 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#include "crypto/rfc6979_hmac_sha256.h"
-
-#include <string.h>
-
-#include <algorithm>
-
-static const unsigned char zero[1] = {0x00};
-static const unsigned char one[1] = {0x01};
-
-RFC6979_HMAC_SHA256::RFC6979_HMAC_SHA256(const unsigned char* key, size_t keylen, const unsigned char* msg, size_t msglen) : retry(false)
-{
-    memset(V, 0x01, sizeof(V));
-    memset(K, 0x00, sizeof(K));
-
-    CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Write(zero, sizeof(zero)).Write(key, keylen).Write(msg, msglen).Finalize(K);
-    CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
-    CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Write(one, sizeof(one)).Write(key, keylen).Write(msg, msglen).Finalize(K);
-    CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
-}
-
-RFC6979_HMAC_SHA256::~RFC6979_HMAC_SHA256()
-{
-    memset(V, 0x01, sizeof(V));
-    memset(K, 0x00, sizeof(K));
-}
-
-void RFC6979_HMAC_SHA256::Generate(unsigned char* output, size_t outputlen)
-{
-    if (retry) {
-        CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Write(zero, sizeof(zero)).Finalize(K);
-        CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
-    }
-
-    while (outputlen > 0) {
-        CHMAC_SHA256(K, sizeof(K)).Write(V, sizeof(V)).Finalize(V);
-        size_t len = std::min(outputlen, sizeof(V));
-        memcpy(output, V, len);
-        output += len;
-        outputlen -= len;
-    }
-
-    retry = true;
-}

src/crypto/rfc6979_hmac_sha256.h

@@ -1,36 +0,0 @@
-// Copyright (c) 2014 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#ifndef BITCOIN_RFC6979_HMAC_SHA256_H
-#define BITCOIN_RFC6979_HMAC_SHA256_H
-
-#include "crypto/hmac_sha256.h"
-
-#include <stdint.h>
-#include <stdlib.h>
-
-/** The RFC 6979 PRNG using HMAC-SHA256. */
-class RFC6979_HMAC_SHA256
-{
-private:
-    unsigned char V[CHMAC_SHA256::OUTPUT_SIZE];
-    unsigned char K[CHMAC_SHA256::OUTPUT_SIZE];
-    bool retry;
-
-public:
-    /**
-     * Construct a new RFC6979 PRNG, using the given key and message.
-     * The message is assumed to be already hashed.
-     */
-    RFC6979_HMAC_SHA256(const unsigned char* key, size_t keylen, const unsigned char* msg, size_t msglen);
-
-    /**
-     * Generate a byte array.
-     */
-    void Generate(unsigned char* output, size_t outputlen);
-
-    ~RFC6979_HMAC_SHA256();
-};
-
-#endif // BITCOIN_RFC6979_HMAC_SHA256_H

src/key.cpp

@@ -6,7 +6,6 @@
 
 #include "arith_uint256.h"
 #include "crypto/hmac_sha512.h"
-#include "crypto/rfc6979_hmac_sha256.h"
 #include "eccryptoverify.h"
 #include "pubkey.h"
 #include "random.h"
@@ -74,23 +73,28 @@ CPubKey CKey::GetPubKey() const {
     return result;
 }
 
+extern "C"
+{
+static int secp256k1_nonce_function_test_case(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, unsigned int attempt, const void *data)
+{
+    const uint32_t *test_case = static_cast<const uint32_t*>(data);
+    uint256 nonce;
+    secp256k1_nonce_function_rfc6979(nonce.begin(), msg32, key32, attempt, NULL);
+    nonce = ArithToUint256(UintToArith256(nonce) + *test_case);
+    memcpy(nonce32, nonce.begin(), 32);
+    return 1;
+}
+}
+
 bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_t test_case) const {
     if (!fValid)
         return false;
     vchSig.resize(72);
-    RFC6979_HMAC_SHA256 prng(begin(), 32, (unsigned char*)&hash, 32);
+    int nSigLen = 72;
-    do {
+    int ret = secp256k1_ecdsa_sign(hash.begin(), (unsigned char*)&vchSig[0], &nSigLen, begin(), test_case == 0 ? secp256k1_nonce_function_rfc6979 : secp256k1_nonce_function_test_case, test_case == 0 ? NULL : &test_case);
-        uint256 nonce;
+    assert(ret);
-        prng.Generate((unsigned char*)&nonce, 32);
+    vchSig.resize(nSigLen);
-        nonce = ArithToUint256(UintToArith256(nonce) + test_case);
+    return true;
-        int nSigLen = 72;
-        int ret = secp256k1_ecdsa_sign((const unsigned char*)&hash, (unsigned char*)&vchSig[0], &nSigLen, begin(), (unsigned char*)&nonce);
-        nonce = uint256();
-        if (ret) {
-            vchSig.resize(nSigLen);
-            return true;
-        }
-    } while(true);
 }
 
 bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
@@ -101,7 +105,7 @@ bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
     std::string str = "Bitcoin key verification\n";
     GetRandBytes(rnd, sizeof(rnd));
     uint256 hash;
-    CHash256().Write((unsigned char*)str.data(), str.size()).Write(rnd, sizeof(rnd)).Finalize((unsigned char*)&hash);
+    CHash256().Write((unsigned char*)str.data(), str.size()).Write(rnd, sizeof(rnd)).Finalize(hash.begin());
     std::vector<unsigned char> vchSig;
     Sign(hash, vchSig);
     return pubkey.Verify(hash, vchSig);
@@ -112,15 +116,8 @@ bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig)
         return false;
     vchSig.resize(65);
     int rec = -1;
-    RFC6979_HMAC_SHA256 prng(begin(), 32, (unsigned char*)&hash, 32);
+    int ret = secp256k1_ecdsa_sign_compact(hash.begin(), &vchSig[1], begin(), secp256k1_nonce_function_rfc6979, NULL, &rec);
-    do {
+    assert(ret);
-        uint256 nonce;
-        prng.Generate((unsigned char*)&nonce, 32);
-        int ret = secp256k1_ecdsa_sign_compact((const unsigned char*)&hash, &vchSig[1], begin(), (unsigned char*)&nonce, &rec);
-        nonce = uint256();
-        if (ret)
-            break;
-    } while(true);
     assert(rec != -1);
     vchSig[0] = 27 + rec + (fCompressed ? 4 : 0);
     return true;

src/test/crypto_tests.cpp

@@ -2,7 +2,6 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include "crypto/rfc6979_hmac_sha256.h"
 #include "crypto/ripemd160.h"
 #include "crypto/sha1.h"
 #include "crypto/sha256.h"
@@ -248,38 +247,4 @@ BOOST_AUTO_TEST_CASE(hmac_sha512_testvectors) {
                    "b6022cac3c4982b10d5eeb55c3e4de15134676fb6de0446065c97440fa8c6a58");
 }
 
-void TestRFC6979(const std::string& hexkey, const std::string& hexmsg, const std::vector<std::string>& hexout)
-{
-    std::vector<unsigned char> key = ParseHex(hexkey);
-    std::vector<unsigned char> msg = ParseHex(hexmsg);
-    RFC6979_HMAC_SHA256 rng(&key[0], key.size(), &msg[0], msg.size());
-
-    for (unsigned int i = 0; i < hexout.size(); i++) {
-        std::vector<unsigned char> out = ParseHex(hexout[i]);
-        std::vector<unsigned char> gen;
-        gen.resize(out.size());
-        rng.Generate(&gen[0], gen.size());
-        BOOST_CHECK(out == gen);
-    }
-}
-
-BOOST_AUTO_TEST_CASE(rfc6979_hmac_sha256)
-{
-    TestRFC6979(
-        "0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f00",
-        "4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a",
-        boost::assign::list_of
-            ("4fe29525b2086809159acdf0506efb86b0ec932c7ba44256ab321e421e67e9fb")
-            ("2bf0fff1d3c378a22dc5de1d856522325c65b504491a0cbd01cb8f3aa67ffd4a")
-            ("f528b410cb541f77000d7afb6c5b53c5c471eab43e466d9ac5190c39c82fd82e"));
-
-    TestRFC6979(
-        "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
-        "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
-        boost::assign::list_of
-            ("9c236c165b82ae0cd590659e100b6bab3036e7ba8b06749baf6981e16f1a2b95")
-            ("df471061625bc0ea14b682feee2c9c02f235da04204c1d62a1536c6e17aed7a9")
-            ("7597887cbd76321f32e30440679a22cf7f8d9d2eac390e581fea091ce202ba94"));
-}
-
 BOOST_AUTO_TEST_SUITE_END()