diff --git a/src/Makefile.am b/src/Makefile.am
index 0d45203c90..e1e6915185 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -203,10 +203,14 @@ 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_sha512.cpp \
   crypto/ripemd160.cpp \
   crypto/common.h \
-  crypto/sha2.h \
+  crypto/sha256.h \
+  crypto/sha512.h \
+  crypto/hmac_sha512.h \
   crypto/sha1.h \
   crypto/ripemd160.h
 
@@ -342,8 +346,10 @@ 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_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..8c65785104
--- /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_HMAC_SHA512_H
+#define BITCOIN_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_HMAC_SHA512_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..a57dce0227
--- /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_SHA256_H
+#define BITCOIN_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_SHA256_H
diff --git a/src/crypto/sha2.cpp b/src/crypto/sha512.cpp
similarity index 53%
rename from src/crypto/sha2.cpp
rename to 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..4d1345e50b
--- /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_SHA512_H
+#define BITCOIN_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_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 76256b864c..9b3cf8f019 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -4,7 +4,7 @@
 
 #include "key.h"
 
-#include "crypto/sha2.h"
+#include "crypto/hmac_sha512.h"
 #include "eccryptoverify.h"
 #include "pubkey.h"
 #include "random.h"
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 760086eaba..6038adda94 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..b3783133d5 100644
--- a/src/test/crypto_tests.cpp
+++ b/src/test/crypto_tests.cpp
@@ -4,7 +4,9 @@
 
 #include "crypto/ripemd160.h"
 #include "crypto/sha1.h"
-#include "crypto/sha2.h"
+#include "crypto/sha256.h"
+#include "crypto/sha512.h"
+#include "crypto/hmac_sha512.h"
 #include "random.h"
 #include "utilstrencodings.h"