Merge pull request #5227

4cdaa95 Resize after succesful result (Pieter Wuille)
9d8604f Header define style cleanups (Pieter Wuille)
a53fd41 Deterministic signing (Pieter Wuille)
3060e36 Add the RFC6979 PRNG (Pieter Wuille)
a8f5087 Add HMAC-SHA256 (Pieter Wuille)
36fa4a7 Split up crypto/sha2 (Pieter Wuille)

21 files changed, 612 insertions, 293 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 3ec9e2f85d..4c4f9f6937 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -203,10 +203,18 @@ libbitcoin_wallet_a_SOURCES = \
 crypto_libbitcoin_crypto_a_CPPFLAGS = $(BITCOIN_CONFIG_INCLUDES)
 crypto_libbitcoin_crypto_a_SOURCES = \
   crypto/sha1.cpp \
-  crypto/sha2.cpp \
+  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/sha2.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
 
@@ -343,8 +351,10 @@ if BUILD_BITCOIN_LIBS
 include_HEADERS = script/bitcoinconsensus.h
 libbitcoinconsensus_la_SOURCES = \
   core/transaction.cpp \
+  crypto/hmac_sha512.cpp \
   crypto/sha1.cpp \
-  crypto/sha2.cpp \
+  crypto/sha256.cpp \
+  crypto/sha512.cpp \
   crypto/ripemd160.cpp \
   eccryptoverify.cpp \
   ecwrapper.cpp \
diff --git a/src/crypto/hmac_sha256.cpp b/src/crypto/hmac_sha256.cpp
new file mode 100644
index 0000000000..435896538b
--- /dev/null
+++ b/src/crypto/hmac_sha256.cpp
@@ -0,0 +1,34 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "crypto/hmac_sha256.h"
+
+#include <string.h>
+
+CHMAC_SHA256::CHMAC_SHA256(const unsigned char* key, size_t keylen)
+{
+    unsigned char rkey[64];
+    if (keylen <= 64) {
+        memcpy(rkey, key, keylen);
+        memset(rkey + keylen, 0, 64 - keylen);
+    } else {
+        CSHA256().Write(key, keylen).Finalize(rkey);
+        memset(rkey + 32, 0, 32);
+    }
+
+    for (int n = 0; n < 64; n++)
+        rkey[n] ^= 0x5c;
+    outer.Write(rkey, 64);
+
+    for (int n = 0; n < 64; n++)
+        rkey[n] ^= 0x5c ^ 0x36;
+    inner.Write(rkey, 64);
+}
+
+void CHMAC_SHA256::Finalize(unsigned char hash[OUTPUT_SIZE])
+{
+    unsigned char temp[32];
+    inner.Finalize(temp);
+    outer.Write(temp, 32).Finalize(hash);
+}
diff --git a/src/crypto/hmac_sha256.h b/src/crypto/hmac_sha256.h
new file mode 100644
index 0000000000..1fdee5a7cd
--- /dev/null
+++ b/src/crypto/hmac_sha256.h
@@ -0,0 +1,32 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_CRYPTO_HMAC_SHA256_H
+#define BITCOIN_CRYPTO_HMAC_SHA256_H
+
+#include "crypto/sha256.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+
+/** A hasher class for HMAC-SHA-512. */
+class CHMAC_SHA256
+{
+private:
+    CSHA256 outer;
+    CSHA256 inner;
+
+public:
+    static const size_t OUTPUT_SIZE = 32;
+
+    CHMAC_SHA256(const unsigned char* key, size_t keylen);
+    CHMAC_SHA256& Write(const unsigned char* data, size_t len)
+    {
+        inner.Write(data, len);
+        return *this;
+    }
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
+};
+
+#endif // BITCOIN_CRYPTO_HMAC_SHA256_H
diff --git a/src/crypto/hmac_sha512.cpp b/src/crypto/hmac_sha512.cpp
new file mode 100644
index 0000000000..940a93277c
--- /dev/null
+++ b/src/crypto/hmac_sha512.cpp
@@ -0,0 +1,34 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "crypto/hmac_sha512.h"
+
+#include <string.h>
+
+CHMAC_SHA512::CHMAC_SHA512(const unsigned char* key, size_t keylen)
+{
+    unsigned char rkey[128];
+    if (keylen <= 128) {
+        memcpy(rkey, key, keylen);
+        memset(rkey + keylen, 0, 128 - keylen);
+    } else {
+        CSHA512().Write(key, keylen).Finalize(rkey);
+        memset(rkey + 64, 0, 64);
+    }
+
+    for (int n = 0; n < 128; n++)
+        rkey[n] ^= 0x5c;
+    outer.Write(rkey, 128);
+
+    for (int n = 0; n < 128; n++)
+        rkey[n] ^= 0x5c ^ 0x36;
+    inner.Write(rkey, 128);
+}
+
+void CHMAC_SHA512::Finalize(unsigned char hash[OUTPUT_SIZE])
+{
+    unsigned char temp[64];
+    inner.Finalize(temp);
+    outer.Write(temp, 64).Finalize(hash);
+}
diff --git a/src/crypto/hmac_sha512.h b/src/crypto/hmac_sha512.h
new file mode 100644
index 0000000000..17d75021aa
--- /dev/null
+++ b/src/crypto/hmac_sha512.h
@@ -0,0 +1,32 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_CRYPTO_HMAC_SHA512_H
+#define BITCOIN_CRYPTO_HMAC_SHA512_H
+
+#include "crypto/sha512.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+
+/** A hasher class for HMAC-SHA-512. */
+class CHMAC_SHA512
+{
+private:
+    CSHA512 outer;
+    CSHA512 inner;
+
+public:
+    static const size_t OUTPUT_SIZE = 64;
+
+    CHMAC_SHA512(const unsigned char* key, size_t keylen);
+    CHMAC_SHA512& Write(const unsigned char* data, size_t len)
+    {
+        inner.Write(data, len);
+        return *this;
+    }
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
+};
+
+#endif // BITCOIN_CRYPTO_HMAC_SHA512_H
diff --git a/src/crypto/rfc6979_hmac_sha256.cpp b/src/crypto/rfc6979_hmac_sha256.cpp
new file mode 100644
index 0000000000..3f935abfea
--- /dev/null
+++ b/src/crypto/rfc6979_hmac_sha256.cpp
@@ -0,0 +1,47 @@
+// Copyright (c) 2014 The Bitcoin 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;
+}
diff --git a/src/crypto/rfc6979_hmac_sha256.h b/src/crypto/rfc6979_hmac_sha256.h
new file mode 100644
index 0000000000..e67ddcf8fe
--- /dev/null
+++ b/src/crypto/rfc6979_hmac_sha256.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2014 The Bitcoin 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
diff --git a/src/crypto/sha2.h b/src/crypto/sha2.h
deleted file mode 100644
index 329c6675ab..0000000000
--- a/src/crypto/sha2.h
+++ /dev/null
@@ -1,64 +0,0 @@
-// Copyright (c) 2014 The Bitcoin developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#ifndef BITCOIN_CRYPTO_SHA2_H
-#define BITCOIN_CRYPTO_SHA2_H
-
-#include <stdint.h>
-#include <stdlib.h>
-
-/** A hasher class for SHA-256. */
-class CSHA256
-{
-private:
-    uint32_t s[8];
-    unsigned char buf[64];
-    size_t bytes;
-
-public:
-    static const size_t OUTPUT_SIZE = 32;
-
-    CSHA256();
-    CSHA256& Write(const unsigned char* data, size_t len);
-    void Finalize(unsigned char hash[OUTPUT_SIZE]);
-    CSHA256& Reset();
-};
-
-/** A hasher class for SHA-512. */
-class CSHA512
-{
-private:
-    uint64_t s[8];
-    unsigned char buf[128];
-    size_t bytes;
-
-public:
-    static const size_t OUTPUT_SIZE = 64;
-
-    CSHA512();
-    CSHA512& Write(const unsigned char* data, size_t len);
-    void Finalize(unsigned char hash[OUTPUT_SIZE]);
-    CSHA512& Reset();
-};
-
-/** A hasher class for HMAC-SHA-512. */
-class CHMAC_SHA512
-{
-private:
-    CSHA512 outer;
-    CSHA512 inner;
-
-public:
-    static const size_t OUTPUT_SIZE = 64;
-
-    CHMAC_SHA512(const unsigned char* key, size_t keylen);
-    CHMAC_SHA512& Write(const unsigned char* data, size_t len)
-    {
-        inner.Write(data, len);
-        return *this;
-    }
-    void Finalize(unsigned char hash[OUTPUT_SIZE]);
-};
-
-#endif // BITCOIN_CRYPTO_SHA2_H
diff --git a/src/crypto/sha256.cpp b/src/crypto/sha256.cpp
new file mode 100644
index 0000000000..8410e59305
--- /dev/null
+++ b/src/crypto/sha256.cpp
@@ -0,0 +1,189 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "crypto/sha256.h"
+
+#include "crypto/common.h"
+
+#include <string.h>
+
+// Internal implementation code.
+namespace
+{
+/// Internal SHA-256 implementation.
+namespace sha256
+{
+uint32_t inline Ch(uint32_t x, uint32_t y, uint32_t z) { return z ^ (x & (y ^ z)); }
+uint32_t inline Maj(uint32_t x, uint32_t y, uint32_t z) { return (x & y) | (z & (x | y)); }
+uint32_t inline Sigma0(uint32_t x) { return (x >> 2 | x << 30) ^ (x >> 13 | x << 19) ^ (x >> 22 | x << 10); }
+uint32_t inline Sigma1(uint32_t x) { return (x >> 6 | x << 26) ^ (x >> 11 | x << 21) ^ (x >> 25 | x << 7); }
+uint32_t inline sigma0(uint32_t x) { return (x >> 7 | x << 25) ^ (x >> 18 | x << 14) ^ (x >> 3); }
+uint32_t inline sigma1(uint32_t x) { return (x >> 17 | x << 15) ^ (x >> 19 | x << 13) ^ (x >> 10); }
+
+/** One round of SHA-256. */
+void inline Round(uint32_t a, uint32_t b, uint32_t c, uint32_t& d, uint32_t e, uint32_t f, uint32_t g, uint32_t& h, uint32_t k, uint32_t w)
+{
+    uint32_t t1 = h + Sigma1(e) + Ch(e, f, g) + k + w;
+    uint32_t t2 = Sigma0(a) + Maj(a, b, c);
+    d += t1;
+    h = t1 + t2;
+}
+
+/** Initialize SHA-256 state. */
+void inline Initialize(uint32_t* s)
+{
+    s[0] = 0x6a09e667ul;
+    s[1] = 0xbb67ae85ul;
+    s[2] = 0x3c6ef372ul;
+    s[3] = 0xa54ff53aul;
+    s[4] = 0x510e527ful;
+    s[5] = 0x9b05688cul;
+    s[6] = 0x1f83d9abul;
+    s[7] = 0x5be0cd19ul;
+}
+
+/** Perform one SHA-256 transformation, processing a 64-byte chunk. */
+void Transform(uint32_t* s, const unsigned char* chunk)
+{
+    uint32_t a = s[0], b = s[1], c = s[2], d = s[3], e = s[4], f = s[5], g = s[6], h = s[7];
+    uint32_t w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;
+
+    Round(a, b, c, d, e, f, g, h, 0x428a2f98, w0 = ReadBE32(chunk + 0));
+    Round(h, a, b, c, d, e, f, g, 0x71374491, w1 = ReadBE32(chunk + 4));
+    Round(g, h, a, b, c, d, e, f, 0xb5c0fbcf, w2 = ReadBE32(chunk + 8));
+    Round(f, g, h, a, b, c, d, e, 0xe9b5dba5, w3 = ReadBE32(chunk + 12));
+    Round(e, f, g, h, a, b, c, d, 0x3956c25b, w4 = ReadBE32(chunk + 16));
+    Round(d, e, f, g, h, a, b, c, 0x59f111f1, w5 = ReadBE32(chunk + 20));
+    Round(c, d, e, f, g, h, a, b, 0x923f82a4, w6 = ReadBE32(chunk + 24));
+    Round(b, c, d, e, f, g, h, a, 0xab1c5ed5, w7 = ReadBE32(chunk + 28));
+    Round(a, b, c, d, e, f, g, h, 0xd807aa98, w8 = ReadBE32(chunk + 32));
+    Round(h, a, b, c, d, e, f, g, 0x12835b01, w9 = ReadBE32(chunk + 36));
+    Round(g, h, a, b, c, d, e, f, 0x243185be, w10 = ReadBE32(chunk + 40));
+    Round(f, g, h, a, b, c, d, e, 0x550c7dc3, w11 = ReadBE32(chunk + 44));
+    Round(e, f, g, h, a, b, c, d, 0x72be5d74, w12 = ReadBE32(chunk + 48));
+    Round(d, e, f, g, h, a, b, c, 0x80deb1fe, w13 = ReadBE32(chunk + 52));
+    Round(c, d, e, f, g, h, a, b, 0x9bdc06a7, w14 = ReadBE32(chunk + 56));
+    Round(b, c, d, e, f, g, h, a, 0xc19bf174, w15 = ReadBE32(chunk + 60));
+
+    Round(a, b, c, d, e, f, g, h, 0xe49b69c1, w0 += sigma1(w14) + w9 + sigma0(w1));
+    Round(h, a, b, c, d, e, f, g, 0xefbe4786, w1 += sigma1(w15) + w10 + sigma0(w2));
+    Round(g, h, a, b, c, d, e, f, 0x0fc19dc6, w2 += sigma1(w0) + w11 + sigma0(w3));
+    Round(f, g, h, a, b, c, d, e, 0x240ca1cc, w3 += sigma1(w1) + w12 + sigma0(w4));
+    Round(e, f, g, h, a, b, c, d, 0x2de92c6f, w4 += sigma1(w2) + w13 + sigma0(w5));
+    Round(d, e, f, g, h, a, b, c, 0x4a7484aa, w5 += sigma1(w3) + w14 + sigma0(w6));
+    Round(c, d, e, f, g, h, a, b, 0x5cb0a9dc, w6 += sigma1(w4) + w15 + sigma0(w7));
+    Round(b, c, d, e, f, g, h, a, 0x76f988da, w7 += sigma1(w5) + w0 + sigma0(w8));
+    Round(a, b, c, d, e, f, g, h, 0x983e5152, w8 += sigma1(w6) + w1 + sigma0(w9));
+    Round(h, a, b, c, d, e, f, g, 0xa831c66d, w9 += sigma1(w7) + w2 + sigma0(w10));
+    Round(g, h, a, b, c, d, e, f, 0xb00327c8, w10 += sigma1(w8) + w3 + sigma0(w11));
+    Round(f, g, h, a, b, c, d, e, 0xbf597fc7, w11 += sigma1(w9) + w4 + sigma0(w12));
+    Round(e, f, g, h, a, b, c, d, 0xc6e00bf3, w12 += sigma1(w10) + w5 + sigma0(w13));
+    Round(d, e, f, g, h, a, b, c, 0xd5a79147, w13 += sigma1(w11) + w6 + sigma0(w14));
+    Round(c, d, e, f, g, h, a, b, 0x06ca6351, w14 += sigma1(w12) + w7 + sigma0(w15));
+    Round(b, c, d, e, f, g, h, a, 0x14292967, w15 += sigma1(w13) + w8 + sigma0(w0));
+
+    Round(a, b, c, d, e, f, g, h, 0x27b70a85, w0 += sigma1(w14) + w9 + sigma0(w1));
+    Round(h, a, b, c, d, e, f, g, 0x2e1b2138, w1 += sigma1(w15) + w10 + sigma0(w2));
+    Round(g, h, a, b, c, d, e, f, 0x4d2c6dfc, w2 += sigma1(w0) + w11 + sigma0(w3));
+    Round(f, g, h, a, b, c, d, e, 0x53380d13, w3 += sigma1(w1) + w12 + sigma0(w4));
+    Round(e, f, g, h, a, b, c, d, 0x650a7354, w4 += sigma1(w2) + w13 + sigma0(w5));
+    Round(d, e, f, g, h, a, b, c, 0x766a0abb, w5 += sigma1(w3) + w14 + sigma0(w6));
+    Round(c, d, e, f, g, h, a, b, 0x81c2c92e, w6 += sigma1(w4) + w15 + sigma0(w7));
+    Round(b, c, d, e, f, g, h, a, 0x92722c85, w7 += sigma1(w5) + w0 + sigma0(w8));
+    Round(a, b, c, d, e, f, g, h, 0xa2bfe8a1, w8 += sigma1(w6) + w1 + sigma0(w9));
+    Round(h, a, b, c, d, e, f, g, 0xa81a664b, w9 += sigma1(w7) + w2 + sigma0(w10));
+    Round(g, h, a, b, c, d, e, f, 0xc24b8b70, w10 += sigma1(w8) + w3 + sigma0(w11));
+    Round(f, g, h, a, b, c, d, e, 0xc76c51a3, w11 += sigma1(w9) + w4 + sigma0(w12));
+    Round(e, f, g, h, a, b, c, d, 0xd192e819, w12 += sigma1(w10) + w5 + sigma0(w13));
+    Round(d, e, f, g, h, a, b, c, 0xd6990624, w13 += sigma1(w11) + w6 + sigma0(w14));
+    Round(c, d, e, f, g, h, a, b, 0xf40e3585, w14 += sigma1(w12) + w7 + sigma0(w15));
+    Round(b, c, d, e, f, g, h, a, 0x106aa070, w15 += sigma1(w13) + w8 + sigma0(w0));
+
+    Round(a, b, c, d, e, f, g, h, 0x19a4c116, w0 += sigma1(w14) + w9 + sigma0(w1));
+    Round(h, a, b, c, d, e, f, g, 0x1e376c08, w1 += sigma1(w15) + w10 + sigma0(w2));
+    Round(g, h, a, b, c, d, e, f, 0x2748774c, w2 += sigma1(w0) + w11 + sigma0(w3));
+    Round(f, g, h, a, b, c, d, e, 0x34b0bcb5, w3 += sigma1(w1) + w12 + sigma0(w4));
+    Round(e, f, g, h, a, b, c, d, 0x391c0cb3, w4 += sigma1(w2) + w13 + sigma0(w5));
+    Round(d, e, f, g, h, a, b, c, 0x4ed8aa4a, w5 += sigma1(w3) + w14 + sigma0(w6));
+    Round(c, d, e, f, g, h, a, b, 0x5b9cca4f, w6 += sigma1(w4) + w15 + sigma0(w7));
+    Round(b, c, d, e, f, g, h, a, 0x682e6ff3, w7 += sigma1(w5) + w0 + sigma0(w8));
+    Round(a, b, c, d, e, f, g, h, 0x748f82ee, w8 += sigma1(w6) + w1 + sigma0(w9));
+    Round(h, a, b, c, d, e, f, g, 0x78a5636f, w9 += sigma1(w7) + w2 + sigma0(w10));
+    Round(g, h, a, b, c, d, e, f, 0x84c87814, w10 += sigma1(w8) + w3 + sigma0(w11));
+    Round(f, g, h, a, b, c, d, e, 0x8cc70208, w11 += sigma1(w9) + w4 + sigma0(w12));
+    Round(e, f, g, h, a, b, c, d, 0x90befffa, w12 += sigma1(w10) + w5 + sigma0(w13));
+    Round(d, e, f, g, h, a, b, c, 0xa4506ceb, w13 += sigma1(w11) + w6 + sigma0(w14));
+    Round(c, d, e, f, g, h, a, b, 0xbef9a3f7, w14 + sigma1(w12) + w7 + sigma0(w15));
+    Round(b, c, d, e, f, g, h, a, 0xc67178f2, w15 + sigma1(w13) + w8 + sigma0(w0));
+
+    s[0] += a;
+    s[1] += b;
+    s[2] += c;
+    s[3] += d;
+    s[4] += e;
+    s[5] += f;
+    s[6] += g;
+    s[7] += h;
+}
+
+} // namespace sha256
+} // namespace
+
+
+////// SHA-256
+
+CSHA256::CSHA256() : bytes(0)
+{
+    sha256::Initialize(s);
+}
+
+CSHA256& CSHA256::Write(const unsigned char* data, size_t len)
+{
+    const unsigned char* end = data + len;
+    size_t bufsize = bytes % 64;
+    if (bufsize && bufsize + len >= 64) {
+        // Fill the buffer, and process it.
+        memcpy(buf + bufsize, data, 64 - bufsize);
+        bytes += 64 - bufsize;
+        data += 64 - bufsize;
+        sha256::Transform(s, buf);
+        bufsize = 0;
+    }
+    while (end >= data + 64) {
+        // Process full chunks directly from the source.
+        sha256::Transform(s, data);
+        bytes += 64;
+        data += 64;
+    }
+    if (end > data) {
+        // Fill the buffer with what remains.
+        memcpy(buf + bufsize, data, end - data);
+        bytes += end - data;
+    }
+    return *this;
+}
+
+void CSHA256::Finalize(unsigned char hash[OUTPUT_SIZE])
+{
+    static const unsigned char pad[64] = {0x80};
+    unsigned char sizedesc[8];
+    WriteBE64(sizedesc, bytes << 3);
+    Write(pad, 1 + ((119 - (bytes % 64)) % 64));
+    Write(sizedesc, 8);
+    WriteBE32(hash, s[0]);
+    WriteBE32(hash + 4, s[1]);
+    WriteBE32(hash + 8, s[2]);
+    WriteBE32(hash + 12, s[3]);
+    WriteBE32(hash + 16, s[4]);
+    WriteBE32(hash + 20, s[5]);
+    WriteBE32(hash + 24, s[6]);
+    WriteBE32(hash + 28, s[7]);
+}
+
+CSHA256& CSHA256::Reset()
+{
+    bytes = 0;
+    sha256::Initialize(s);
+    return *this;
+}
diff --git a/src/crypto/sha256.h b/src/crypto/sha256.h
new file mode 100644
index 0000000000..bde1a59bed
--- /dev/null
+++ b/src/crypto/sha256.h
@@ -0,0 +1,28 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_CRYPTO_SHA256_H
+#define BITCOIN_CRYPTO_SHA256_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+/** A hasher class for SHA-256. */
+class CSHA256
+{
+private:
+    uint32_t s[8];
+    unsigned char buf[64];
+    size_t bytes;
+
+public:
+    static const size_t OUTPUT_SIZE = 32;
+
+    CSHA256();
+    CSHA256& Write(const unsigned char* data, size_t len);
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
+    CSHA256& Reset();
+};
+
+#endif // BITCOIN_CRYPTO_SHA256_H
diff --git a/src/crypto/sha2.cpp b/src/crypto/sha512.cpp
index 613aac2d71..22c3103bed 100644
--- a/src/crypto/sha2.cpp
+++ b/src/crypto/sha512.cpp
@@ -2,7 +2,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include "crypto/sha2.h"
+#include "crypto/sha512.h"
 
 #include "crypto/common.h"
 
@@ -11,124 +11,6 @@
 // Internal implementation code.
 namespace
 {
-/// Internal SHA-256 implementation.
-namespace sha256
-{
-uint32_t inline Ch(uint32_t x, uint32_t y, uint32_t z) { return z ^ (x & (y ^ z)); }
-uint32_t inline Maj(uint32_t x, uint32_t y, uint32_t z) { return (x & y) | (z & (x | y)); }
-uint32_t inline Sigma0(uint32_t x) { return (x >> 2 | x << 30) ^ (x >> 13 | x << 19) ^ (x >> 22 | x << 10); }
-uint32_t inline Sigma1(uint32_t x) { return (x >> 6 | x << 26) ^ (x >> 11 | x << 21) ^ (x >> 25 | x << 7); }
-uint32_t inline sigma0(uint32_t x) { return (x >> 7 | x << 25) ^ (x >> 18 | x << 14) ^ (x >> 3); }
-uint32_t inline sigma1(uint32_t x) { return (x >> 17 | x << 15) ^ (x >> 19 | x << 13) ^ (x >> 10); }
-
-/** One round of SHA-256. */
-void inline Round(uint32_t a, uint32_t b, uint32_t c, uint32_t& d, uint32_t e, uint32_t f, uint32_t g, uint32_t& h, uint32_t k, uint32_t w)
-{
-    uint32_t t1 = h + Sigma1(e) + Ch(e, f, g) + k + w;
-    uint32_t t2 = Sigma0(a) + Maj(a, b, c);
-    d += t1;
-    h = t1 + t2;
-}
-
-/** Initialize SHA-256 state. */
-void inline Initialize(uint32_t* s)
-{
-    s[0] = 0x6a09e667ul;
-    s[1] = 0xbb67ae85ul;
-    s[2] = 0x3c6ef372ul;
-    s[3] = 0xa54ff53aul;
-    s[4] = 0x510e527ful;
-    s[5] = 0x9b05688cul;
-    s[6] = 0x1f83d9abul;
-    s[7] = 0x5be0cd19ul;
-}
-
-/** Perform one SHA-256 transformation, processing a 64-byte chunk. */
-void Transform(uint32_t* s, const unsigned char* chunk)
-{
-    uint32_t a = s[0], b = s[1], c = s[2], d = s[3], e = s[4], f = s[5], g = s[6], h = s[7];
-    uint32_t w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;
-
-    Round(a, b, c, d, e, f, g, h, 0x428a2f98, w0 = ReadBE32(chunk + 0));
-    Round(h, a, b, c, d, e, f, g, 0x71374491, w1 = ReadBE32(chunk + 4));
-    Round(g, h, a, b, c, d, e, f, 0xb5c0fbcf, w2 = ReadBE32(chunk + 8));
-    Round(f, g, h, a, b, c, d, e, 0xe9b5dba5, w3 = ReadBE32(chunk + 12));
-    Round(e, f, g, h, a, b, c, d, 0x3956c25b, w4 = ReadBE32(chunk + 16));
-    Round(d, e, f, g, h, a, b, c, 0x59f111f1, w5 = ReadBE32(chunk + 20));
-    Round(c, d, e, f, g, h, a, b, 0x923f82a4, w6 = ReadBE32(chunk + 24));
-    Round(b, c, d, e, f, g, h, a, 0xab1c5ed5, w7 = ReadBE32(chunk + 28));
-    Round(a, b, c, d, e, f, g, h, 0xd807aa98, w8 = ReadBE32(chunk + 32));
-    Round(h, a, b, c, d, e, f, g, 0x12835b01, w9 = ReadBE32(chunk + 36));
-    Round(g, h, a, b, c, d, e, f, 0x243185be, w10 = ReadBE32(chunk + 40));
-    Round(f, g, h, a, b, c, d, e, 0x550c7dc3, w11 = ReadBE32(chunk + 44));
-    Round(e, f, g, h, a, b, c, d, 0x72be5d74, w12 = ReadBE32(chunk + 48));
-    Round(d, e, f, g, h, a, b, c, 0x80deb1fe, w13 = ReadBE32(chunk + 52));
-    Round(c, d, e, f, g, h, a, b, 0x9bdc06a7, w14 = ReadBE32(chunk + 56));
-    Round(b, c, d, e, f, g, h, a, 0xc19bf174, w15 = ReadBE32(chunk + 60));
-
-    Round(a, b, c, d, e, f, g, h, 0xe49b69c1, w0 += sigma1(w14) + w9 + sigma0(w1));
-    Round(h, a, b, c, d, e, f, g, 0xefbe4786, w1 += sigma1(w15) + w10 + sigma0(w2));
-    Round(g, h, a, b, c, d, e, f, 0x0fc19dc6, w2 += sigma1(w0) + w11 + sigma0(w3));
-    Round(f, g, h, a, b, c, d, e, 0x240ca1cc, w3 += sigma1(w1) + w12 + sigma0(w4));
-    Round(e, f, g, h, a, b, c, d, 0x2de92c6f, w4 += sigma1(w2) + w13 + sigma0(w5));
-    Round(d, e, f, g, h, a, b, c, 0x4a7484aa, w5 += sigma1(w3) + w14 + sigma0(w6));
-    Round(c, d, e, f, g, h, a, b, 0x5cb0a9dc, w6 += sigma1(w4) + w15 + sigma0(w7));
-    Round(b, c, d, e, f, g, h, a, 0x76f988da, w7 += sigma1(w5) + w0 + sigma0(w8));
-    Round(a, b, c, d, e, f, g, h, 0x983e5152, w8 += sigma1(w6) + w1 + sigma0(w9));
-    Round(h, a, b, c, d, e, f, g, 0xa831c66d, w9 += sigma1(w7) + w2 + sigma0(w10));
-    Round(g, h, a, b, c, d, e, f, 0xb00327c8, w10 += sigma1(w8) + w3 + sigma0(w11));
-    Round(f, g, h, a, b, c, d, e, 0xbf597fc7, w11 += sigma1(w9) + w4 + sigma0(w12));
-    Round(e, f, g, h, a, b, c, d, 0xc6e00bf3, w12 += sigma1(w10) + w5 + sigma0(w13));
-    Round(d, e, f, g, h, a, b, c, 0xd5a79147, w13 += sigma1(w11) + w6 + sigma0(w14));
-    Round(c, d, e, f, g, h, a, b, 0x06ca6351, w14 += sigma1(w12) + w7 + sigma0(w15));
-    Round(b, c, d, e, f, g, h, a, 0x14292967, w15 += sigma1(w13) + w8 + sigma0(w0));
-
-    Round(a, b, c, d, e, f, g, h, 0x27b70a85, w0 += sigma1(w14) + w9 + sigma0(w1));
-    Round(h, a, b, c, d, e, f, g, 0x2e1b2138, w1 += sigma1(w15) + w10 + sigma0(w2));
-    Round(g, h, a, b, c, d, e, f, 0x4d2c6dfc, w2 += sigma1(w0) + w11 + sigma0(w3));
-    Round(f, g, h, a, b, c, d, e, 0x53380d13, w3 += sigma1(w1) + w12 + sigma0(w4));
-    Round(e, f, g, h, a, b, c, d, 0x650a7354, w4 += sigma1(w2) + w13 + sigma0(w5));
-    Round(d, e, f, g, h, a, b, c, 0x766a0abb, w5 += sigma1(w3) + w14 + sigma0(w6));
-    Round(c, d, e, f, g, h, a, b, 0x81c2c92e, w6 += sigma1(w4) + w15 + sigma0(w7));
-    Round(b, c, d, e, f, g, h, a, 0x92722c85, w7 += sigma1(w5) + w0 + sigma0(w8));
-    Round(a, b, c, d, e, f, g, h, 0xa2bfe8a1, w8 += sigma1(w6) + w1 + sigma0(w9));
-    Round(h, a, b, c, d, e, f, g, 0xa81a664b, w9 += sigma1(w7) + w2 + sigma0(w10));
-    Round(g, h, a, b, c, d, e, f, 0xc24b8b70, w10 += sigma1(w8) + w3 + sigma0(w11));
-    Round(f, g, h, a, b, c, d, e, 0xc76c51a3, w11 += sigma1(w9) + w4 + sigma0(w12));
-    Round(e, f, g, h, a, b, c, d, 0xd192e819, w12 += sigma1(w10) + w5 + sigma0(w13));
-    Round(d, e, f, g, h, a, b, c, 0xd6990624, w13 += sigma1(w11) + w6 + sigma0(w14));
-    Round(c, d, e, f, g, h, a, b, 0xf40e3585, w14 += sigma1(w12) + w7 + sigma0(w15));
-    Round(b, c, d, e, f, g, h, a, 0x106aa070, w15 += sigma1(w13) + w8 + sigma0(w0));
-
-    Round(a, b, c, d, e, f, g, h, 0x19a4c116, w0 += sigma1(w14) + w9 + sigma0(w1));
-    Round(h, a, b, c, d, e, f, g, 0x1e376c08, w1 += sigma1(w15) + w10 + sigma0(w2));
-    Round(g, h, a, b, c, d, e, f, 0x2748774c, w2 += sigma1(w0) + w11 + sigma0(w3));
-    Round(f, g, h, a, b, c, d, e, 0x34b0bcb5, w3 += sigma1(w1) + w12 + sigma0(w4));
-    Round(e, f, g, h, a, b, c, d, 0x391c0cb3, w4 += sigma1(w2) + w13 + sigma0(w5));
-    Round(d, e, f, g, h, a, b, c, 0x4ed8aa4a, w5 += sigma1(w3) + w14 + sigma0(w6));
-    Round(c, d, e, f, g, h, a, b, 0x5b9cca4f, w6 += sigma1(w4) + w15 + sigma0(w7));
-    Round(b, c, d, e, f, g, h, a, 0x682e6ff3, w7 += sigma1(w5) + w0 + sigma0(w8));
-    Round(a, b, c, d, e, f, g, h, 0x748f82ee, w8 += sigma1(w6) + w1 + sigma0(w9));
-    Round(h, a, b, c, d, e, f, g, 0x78a5636f, w9 += sigma1(w7) + w2 + sigma0(w10));
-    Round(g, h, a, b, c, d, e, f, 0x84c87814, w10 += sigma1(w8) + w3 + sigma0(w11));
-    Round(f, g, h, a, b, c, d, e, 0x8cc70208, w11 += sigma1(w9) + w4 + sigma0(w12));
-    Round(e, f, g, h, a, b, c, d, 0x90befffa, w12 += sigma1(w10) + w5 + sigma0(w13));
-    Round(d, e, f, g, h, a, b, c, 0xa4506ceb, w13 += sigma1(w11) + w6 + sigma0(w14));
-    Round(c, d, e, f, g, h, a, b, 0xbef9a3f7, w14 + sigma1(w12) + w7 + sigma0(w15));
-    Round(b, c, d, e, f, g, h, a, 0xc67178f2, w15 + sigma1(w13) + w8 + sigma0(w0));
-
-    s[0] += a;
-    s[1] += b;
-    s[2] += c;
-    s[3] += d;
-    s[4] += e;
-    s[5] += f;
-    s[6] += g;
-    s[7] += h;
-}
-
-} // namespace sha256
-
 /// Internal SHA-512 implementation.
 namespace sha512
 {
@@ -249,8 +131,8 @@ void Transform(uint64_t* s, const unsigned char* chunk)
     Round(f, g, h, a, b, c, d, e, 0x431d67c49c100d4cull, w11 += sigma1(w9) + w4 + sigma0(w12));
     Round(e, f, g, h, a, b, c, d, 0x4cc5d4becb3e42b6ull, w12 += sigma1(w10) + w5 + sigma0(w13));
     Round(d, e, f, g, h, a, b, c, 0x597f299cfc657e2aull, w13 += sigma1(w11) + w6 + sigma0(w14));
-    Round(c, d, e, f, g, h, a, b, 0x5fcb6fab3ad6faecull, w14 += sigma1(w12) + w7 + sigma0(w15));
-    Round(b, c, d, e, f, g, h, a, 0x6c44198c4a475817ull, w15 += sigma1(w13) + w8 + sigma0(w0));
+    Round(c, d, e, f, g, h, a, b, 0x5fcb6fab3ad6faecull, w14 + sigma1(w12) + w7 + sigma0(w15));
+    Round(b, c, d, e, f, g, h, a, 0x6c44198c4a475817ull, w15 + sigma1(w13) + w8 + sigma0(w0));
 
     s[0] += a;
     s[1] += b;
@@ -267,63 +149,6 @@ void Transform(uint64_t* s, const unsigned char* chunk)
 } // namespace
 
 
-////// SHA-256
-
-CSHA256::CSHA256() : bytes(0)
-{
-    sha256::Initialize(s);
-}
-
-CSHA256& CSHA256::Write(const unsigned char* data, size_t len)
-{
-    const unsigned char* end = data + len;
-    size_t bufsize = bytes % 64;
-    if (bufsize && bufsize + len >= 64) {
-        // Fill the buffer, and process it.
-        memcpy(buf + bufsize, data, 64 - bufsize);
-        bytes += 64 - bufsize;
-        data += 64 - bufsize;
-        sha256::Transform(s, buf);
-        bufsize = 0;
-    }
-    while (end >= data + 64) {
-        // Process full chunks directly from the source.
-        sha256::Transform(s, data);
-        bytes += 64;
-        data += 64;
-    }
-    if (end > data) {
-        // Fill the buffer with what remains.
-        memcpy(buf + bufsize, data, end - data);
-        bytes += end - data;
-    }
-    return *this;
-}
-
-void CSHA256::Finalize(unsigned char hash[OUTPUT_SIZE])
-{
-    static const unsigned char pad[64] = {0x80};
-    unsigned char sizedesc[8];
-    WriteBE64(sizedesc, bytes << 3);
-    Write(pad, 1 + ((119 - (bytes % 64)) % 64));
-    Write(sizedesc, 8);
-    WriteBE32(hash, s[0]);
-    WriteBE32(hash + 4, s[1]);
-    WriteBE32(hash + 8, s[2]);
-    WriteBE32(hash + 12, s[3]);
-    WriteBE32(hash + 16, s[4]);
-    WriteBE32(hash + 20, s[5]);
-    WriteBE32(hash + 24, s[6]);
-    WriteBE32(hash + 28, s[7]);
-}
-
-CSHA256& CSHA256::Reset()
-{
-    bytes = 0;
-    sha256::Initialize(s);
-    return *this;
-}
-
 ////// SHA-512
 
 CSHA512::CSHA512() : bytes(0)
@@ -380,32 +205,3 @@ CSHA512& CSHA512::Reset()
     sha512::Initialize(s);
     return *this;
 }
-
-////// HMAC-SHA-512
-
-CHMAC_SHA512::CHMAC_SHA512(const unsigned char* key, size_t keylen)
-{
-    unsigned char rkey[128];
-    if (keylen <= 128) {
-        memcpy(rkey, key, keylen);
-        memset(rkey + keylen, 0, 128 - keylen);
-    } else {
-        CSHA512().Write(key, keylen).Finalize(rkey);
-        memset(rkey + 64, 0, 64);
-    }
-
-    for (int n = 0; n < 128; n++)
-        rkey[n] ^= 0x5c;
-    outer.Write(rkey, 128);
-
-    for (int n = 0; n < 128; n++)
-        rkey[n] ^= 0x5c ^ 0x36;
-    inner.Write(rkey, 128);
-}
-
-void CHMAC_SHA512::Finalize(unsigned char hash[OUTPUT_SIZE])
-{
-    unsigned char temp[64];
-    inner.Finalize(temp);
-    outer.Write(temp, 64).Finalize(hash);
-}
diff --git a/src/crypto/sha512.h b/src/crypto/sha512.h
new file mode 100644
index 0000000000..5566d5db3e
--- /dev/null
+++ b/src/crypto/sha512.h
@@ -0,0 +1,28 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_CRYPTO_SHA512_H
+#define BITCOIN_CRYPTO_SHA512_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+/** A hasher class for SHA-512. */
+class CSHA512
+{
+private:
+    uint64_t s[8];
+    unsigned char buf[128];
+    size_t bytes;
+
+public:
+    static const size_t OUTPUT_SIZE = 64;
+
+    CSHA512();
+    CSHA512& Write(const unsigned char* data, size_t len);
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
+    CSHA512& Reset();
+};
+
+#endif // BITCOIN_CRYPTO_SHA512_H
diff --git a/src/hash.cpp b/src/hash.cpp
index 2cca06ae23..aaca00ea2d 100644
--- a/src/hash.cpp
+++ b/src/hash.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "hash.h"
+#include "crypto/hmac_sha512.h"
 
 inline uint32_t ROTL32(uint32_t x, int8_t r)
 {
diff --git a/src/hash.h b/src/hash.h
index 75695160e6..5a34cdc5c3 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -7,7 +7,7 @@
 #define BITCOIN_HASH_H
 
 #include "crypto/ripemd160.h"
-#include "crypto/sha2.h"
+#include "crypto/sha256.h"
 #include "serialize.h"
 #include "uint256.h"
 #include "version.h"
diff --git a/src/key.cpp b/src/key.cpp
index a91ed1cc1d..acf62360a4 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -4,7 +4,8 @@
 
 #include "key.h"
 
-#include "crypto/sha2.h"
+#include "crypto/hmac_sha512.h"
+#include "crypto/rfc6979_hmac_sha256.h"
 #include "eccryptoverify.h"
 #include "pubkey.h"
 #include "random.h"
@@ -71,19 +72,23 @@ CPubKey CKey::GetPubKey() const {
     return result;
 }
 
-bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
+bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_t test_case) const {
     if (!fValid)
         return false;
     vchSig.resize(72);
-    int nSigLen = 72;
-    CKey nonce;
+    RFC6979_HMAC_SHA256 prng(begin(), 32, (unsigned char*)&hash, 32);
     do {
-        nonce.MakeNewKey(true);
-        if (secp256k1_ecdsa_sign((const unsigned char*)&hash, 32, (unsigned char*)&vchSig[0], &nSigLen, begin(), nonce.begin()))
-            break;
+        uint256 nonce;
+        prng.Generate((unsigned char*)&nonce, 32);
+        nonce += test_case;
+        int nSigLen = 72;
+        int ret = secp256k1_ecdsa_sign((const unsigned char*)&hash, 32, (unsigned char*)&vchSig[0], &nSigLen, begin(), (unsigned char*)&nonce);
+        nonce = 0;
+        if (ret) {
+            vchSig.resize(nSigLen);
+            return true;
+        }
     } while(true);
-    vchSig.resize(nSigLen);
-    return true;
 }
 
 bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
@@ -105,10 +110,13 @@ bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig)
         return false;
     vchSig.resize(65);
     int rec = -1;
-    CKey nonce;
+    RFC6979_HMAC_SHA256 prng(begin(), 32, (unsigned char*)&hash, 32);
     do {
-        nonce.MakeNewKey(true);
-        if (secp256k1_ecdsa_sign_compact((const unsigned char*)&hash, 32, &vchSig[1], begin(), nonce.begin(), &rec))
+        uint256 nonce;
+        prng.Generate((unsigned char*)&nonce, 32);
+        int ret = secp256k1_ecdsa_sign_compact((const unsigned char*)&hash, 32, &vchSig[1], begin(), (unsigned char*)&nonce, &rec);
+        nonce = 0;
+        if (ret)
             break;
     } while(true);
     assert(rec != -1);
diff --git a/src/key.h b/src/key.h
index 228cc42449..d85abe095c 100644
--- a/src/key.h
+++ b/src/key.h
@@ -122,8 +122,12 @@ public:
      */
     CPubKey GetPubKey() const;
 
-    //! Create a DER-serialized signature.
-    bool Sign(const uint256& hash, std::vector<unsigned char>& vchSig) const;
+    /**
+     * Create a DER-serialized signature.
+     * The test_case parameter tweaks the deterministic nonce, and is only for
+     * testing. It should be zero for normal use.
+     */
+    bool Sign(const uint256& hash, std::vector<unsigned char>& vchSig, uint32_t test_case = 0) const;
 
     /**
      * Create a compact signature (65 bytes), which allows reconstructing the used public key.
diff --git a/src/pubkey.cpp b/src/pubkey.cpp
index 9c6f536f21..91979ff4dc 100644
--- a/src/pubkey.cpp
+++ b/src/pubkey.cpp
@@ -4,7 +4,6 @@
 
 #include "pubkey.h"
 
-#include "crypto/sha2.h"
 #include "eccryptoverify.h"
 
 #ifdef USE_SECP256K1
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index a10cefcc0b..237c712870 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -8,7 +8,7 @@
 #include "core/transaction.h"
 #include "crypto/ripemd160.h"
 #include "crypto/sha1.h"
-#include "crypto/sha2.h"
+#include "crypto/sha256.h"
 #include "eccryptoverify.h"
 #include "pubkey.h"
 #include "script/script.h"
diff --git a/src/test/crypto_tests.cpp b/src/test/crypto_tests.cpp
index 68232a2ff1..26708f5071 100644
--- a/src/test/crypto_tests.cpp
+++ b/src/test/crypto_tests.cpp
@@ -2,14 +2,19 @@
 // Distributed under the MIT/X11 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/sha2.h"
+#include "crypto/sha256.h"
+#include "crypto/sha512.h"
+#include "crypto/hmac_sha256.h"
+#include "crypto/hmac_sha512.h"
 #include "random.h"
 #include "utilstrencodings.h"
 
 #include <vector>
 
+#include <boost/assign/list_of.hpp>
 #include <boost/test/unit_test.hpp>
 
 BOOST_AUTO_TEST_SUITE(crypto_tests)
@@ -48,6 +53,11 @@ void TestSHA256(const std::string &in, const std::string &hexout) { TestVector(C
 void TestSHA512(const std::string &in, const std::string &hexout) { TestVector(CSHA512(), in, ParseHex(hexout));}
 void TestRIPEMD160(const std::string &in, const std::string &hexout) { TestVector(CRIPEMD160(), in, ParseHex(hexout));}
 
+void TestHMACSHA256(const std::string &hexkey, const std::string &hexin, const std::string &hexout) {
+    std::vector<unsigned char> key = ParseHex(hexkey);
+    TestVector(CHMAC_SHA256(&key[0], key.size()), ParseHex(hexin), ParseHex(hexout));
+}
+
 void TestHMACSHA512(const std::string &hexkey, const std::string &hexin, const std::string &hexout) {
     std::vector<unsigned char> key = ParseHex(hexkey);
     TestVector(CHMAC_SHA512(&key[0], key.size()), ParseHex(hexin), ParseHex(hexout));
@@ -158,6 +168,43 @@ BOOST_AUTO_TEST_CASE(sha512_testvectors) {
                "37de8c3ef5459d76a52cedc02dc499a3c9ed9dedbfb3281afd9653b8a112fafc");
 }
 
+BOOST_AUTO_TEST_CASE(hmac_sha256_testvectors) {
+    // test cases 1, 2, 3, 4, 6 and 7 of RFC 4231
+    TestHMACSHA256("0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
+                   "4869205468657265",
+                   "b0344c61d8db38535ca8afceaf0bf12b881dc200c9833da726e9376c2e32cff7");
+    TestHMACSHA256("4a656665",
+                   "7768617420646f2079612077616e7420666f72206e6f7468696e673f",
+                   "5bdcc146bf60754e6a042426089575c75a003f089d2739839dec58b964ec3843");
+    TestHMACSHA256("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+                   "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+                   "dddddddddddddddddddddddddddddddddddd",
+                   "773ea91e36800e46854db8ebd09181a72959098b3ef8c122d9635514ced565fe");
+    TestHMACSHA256("0102030405060708090a0b0c0d0e0f10111213141516171819",
+                   "cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd"
+                   "cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd",
+                   "82558a389a443c0ea4cc819899f2083a85f0faa3e578f8077a2e3ff46729665b");
+    TestHMACSHA256("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaa",
+                   "54657374205573696e67204c6172676572205468616e20426c6f636b2d53697a"
+                   "65204b6579202d2048617368204b6579204669727374",
+                   "60e431591ee0b67f0d8a26aacbf5b77f8e0bc6213728c5140546040f0ee37f54");
+    TestHMACSHA256("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+                   "aaaaaa",
+                   "5468697320697320612074657374207573696e672061206c6172676572207468"
+                   "616e20626c6f636b2d73697a65206b657920616e642061206c61726765722074"
+                   "68616e20626c6f636b2d73697a6520646174612e20546865206b6579206e6565"
+                   "647320746f20626520686173686564206265666f7265206265696e6720757365"
+                   "642062792074686520484d414320616c676f726974686d2e",
+                   "9b09ffa71b942fcb27635fbcd5b0e944bfdc63644f0713938a7f51535c3a35e2");
+}
+
 BOOST_AUTO_TEST_CASE(hmac_sha512_testvectors) {
     // test cases 1, 2, 3, 4, 6 and 7 of RFC 4231
     TestHMACSHA512("0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
@@ -201,4 +248,38 @@ 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()
diff --git a/src/test/key_tests.cpp b/src/test/key_tests.cpp
index f9e35e0166..43b18ce61e 100644
--- a/src/test/key_tests.cpp
+++ b/src/test/key_tests.cpp
@@ -8,6 +8,7 @@
 #include "script/script.h"
 #include "uint256.h"
 #include "util.h"
+#include "utilstrencodings.h"
 
 #include <string>
 #include <vector>
@@ -162,6 +163,28 @@ BOOST_AUTO_TEST_CASE(key_test1)
         BOOST_CHECK(rkey1C == pubkey1C);
         BOOST_CHECK(rkey2C == pubkey2C);
     }
+
+    // test deterministic signing
+
+    std::vector<unsigned char> detsig, detsigc;
+    string strMsg = "Very deterministic message";
+    uint256 hashMsg = Hash(strMsg.begin(), strMsg.end());
+    BOOST_CHECK(key1.Sign(hashMsg, detsig));
+    BOOST_CHECK(key1C.Sign(hashMsg, detsigc));
+    BOOST_CHECK(detsig == detsigc);
+    BOOST_CHECK(detsig == ParseHex("304402205dbbddda71772d95ce91cd2d14b592cfbc1dd0aabd6a394b6c2d377bbe59d31d022014ddda21494a4e221f0824f0b8b924c43fa43c0ad57dccdaa11f81a6bd4582f6"));
+    BOOST_CHECK(key2.Sign(hashMsg, detsig));
+    BOOST_CHECK(key2C.Sign(hashMsg, detsigc));
+    BOOST_CHECK(detsig == detsigc);
+    BOOST_CHECK(detsig == ParseHex("3044022052d8a32079c11e79db95af63bb9600c5b04f21a9ca33dc129c2bfa8ac9dc1cd5022061d8ae5e0f6c1a16bde3719c64c2fd70e404b6428ab9a69566962e8771b5944d"));
+    BOOST_CHECK(key1.SignCompact(hashMsg, detsig));
+    BOOST_CHECK(key1C.SignCompact(hashMsg, detsigc));
+    BOOST_CHECK(detsig == ParseHex("1c5dbbddda71772d95ce91cd2d14b592cfbc1dd0aabd6a394b6c2d377bbe59d31d14ddda21494a4e221f0824f0b8b924c43fa43c0ad57dccdaa11f81a6bd4582f6"));
+    BOOST_CHECK(detsigc == ParseHex("205dbbddda71772d95ce91cd2d14b592cfbc1dd0aabd6a394b6c2d377bbe59d31d14ddda21494a4e221f0824f0b8b924c43fa43c0ad57dccdaa11f81a6bd4582f6"));
+    BOOST_CHECK(key2.SignCompact(hashMsg, detsig));
+    BOOST_CHECK(key2C.SignCompact(hashMsg, detsigc));
+    BOOST_CHECK(detsig == ParseHex("1c52d8a32079c11e79db95af63bb9600c5b04f21a9ca33dc129c2bfa8ac9dc1cd561d8ae5e0f6c1a16bde3719c64c2fd70e404b6428ab9a69566962e8771b5944d"));
+    BOOST_CHECK(detsigc == ParseHex("2052d8a32079c11e79db95af63bb9600c5b04f21a9ca33dc129c2bfa8ac9dc1cd561d8ae5e0f6c1a16bde3719c64c2fd70e404b6428ab9a69566962e8771b5944d"));
 }
 
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 6952f4c584..53411190eb 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -248,8 +248,9 @@ public:
     {
         uint256 hash = SignatureHash(scriptPubKey, spendTx, 0, nHashType);
         std::vector<unsigned char> vchSig, r, s;
+        uint32_t iter = 0;
         do {
-            key.Sign(hash, vchSig);
+            key.Sign(hash, vchSig, iter++);
             if ((lenS == 33) != (vchSig[5 + vchSig[3]] == 33)) {
                 NegateSignatureS(vchSig);
             }