Add SipHash-2-4 primitives to hash

1 files changed, 94 insertions, 0 deletions

diff --git a/src/hash.cpp b/src/hash.cpp
index 7f3cf1a1fa..a518314a53 100644
--- a/src/hash.cpp
+++ b/src/hash.cpp
@@ -81,3 +81,97 @@ void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char he
     num[3] = (nChild >>  0) & 0xFF;
     CHMAC_SHA512(chainCode.begin(), chainCode.size()).Write(&header, 1).Write(data, 32).Write(num, 4).Finalize(output);
 }
+
+#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
+
+#define SIPROUND do { \
+    v0 += v1; v1 = ROTL(v1, 13); v1 ^= v0; \
+    v0 = ROTL(v0, 32); \
+    v2 += v3; v3 = ROTL(v3, 16); v3 ^= v2; \
+    v0 += v3; v3 = ROTL(v3, 21); v3 ^= v0; \
+    v2 += v1; v1 = ROTL(v1, 17); v1 ^= v2; \
+    v2 = ROTL(v2, 32); \
+} while (0)
+
+CSipHasher::CSipHasher(uint64_t k0, uint64_t k1)
+{
+    v[0] = 0x736f6d6570736575ULL ^ k0;
+    v[1] = 0x646f72616e646f6dULL ^ k1;
+    v[2] = 0x6c7967656e657261ULL ^ k0;
+    v[3] = 0x7465646279746573ULL ^ k1;
+    count = 0;
+}
+
+CSipHasher& CSipHasher::Write(uint64_t data)
+{
+    uint64_t v0 = v[0], v1 = v[1], v2 = v[2], v3 = v[3];
+
+    v3 ^= data;
+    SIPROUND;
+    SIPROUND;
+    v0 ^= data;
+
+    v[0] = v0;
+    v[1] = v1;
+    v[2] = v2;
+    v[3] = v3;
+
+    count++;
+    return *this;
+}
+
+uint64_t CSipHasher::Finalize() const
+{
+    uint64_t v0 = v[0], v1 = v[1], v2 = v[2], v3 = v[3];
+
+    v3 ^= ((uint64_t)count) << 59;
+    SIPROUND;
+    SIPROUND;
+    v0 ^= ((uint64_t)count) << 59;
+    v2 ^= 0xFF;
+    SIPROUND;
+    SIPROUND;
+    SIPROUND;
+    SIPROUND;
+    return v0 ^ v1 ^ v2 ^ v3;
+}
+
+uint64_t SipHashUint256(uint64_t k0, uint64_t k1, const uint256& val)
+{
+    /* Specialized implementation for efficiency */
+    uint64_t d = val.GetUint64(0);
+
+    uint64_t v0 = 0x736f6d6570736575ULL ^ k0;
+    uint64_t v1 = 0x646f72616e646f6dULL ^ k1;
+    uint64_t v2 = 0x6c7967656e657261ULL ^ k0;
+    uint64_t v3 = 0x7465646279746573ULL ^ k1 ^ d;
+
+    SIPROUND;
+    SIPROUND;
+    v0 ^= d;
+    d = val.GetUint64(1);
+    v3 ^= d;
+    SIPROUND;
+    SIPROUND;
+    v0 ^= d;
+    d = val.GetUint64(2);
+    v3 ^= d;
+    SIPROUND;
+    SIPROUND;
+    v0 ^= d;
+    d = val.GetUint64(3);
+    v3 ^= d;
+    SIPROUND;
+    SIPROUND;
+    v0 ^= d;
+    v3 ^= ((uint64_t)4) << 59;
+    SIPROUND;
+    SIPROUND;
+    v0 ^= ((uint64_t)4) << 59;
+    v2 ^= 0xFF;
+    SIPROUND;
+    SIPROUND;
+    SIPROUND;
+    SIPROUND;
+    return v0 ^ v1 ^ v2 ^ v3;
+}