/* Crypto/Sha256.c -- SHA-256 Hash function

 2008-11-06 : Igor Pavlov : Public domain

 This code is based on public domain code from Wei Dai's Crypto++ library. */

 

 #include "Sha256.h"

 #include "RotateDefs.h"

 

 /* define it for speed optimization */

 /* #define _SHA256_UNROLL */

 /* #define _SHA256_UNROLL2 */

 

 void Sha256_Init(CSha256 *p)

 {

   p->state[0] = 0x6a09e667;

   p->state[1] = 0xbb67ae85;

   p->state[2] = 0x3c6ef372;

   p->state[3] = 0xa54ff53a;

   p->state[4] = 0x510e527f;

   p->state[5] = 0x9b05688c;

   p->state[6] = 0x1f83d9ab;

   p->state[7] = 0x5be0cd19;

   p->count = 0;

 }

 

 #define S0(x) (rotrFixed(x, 2) ^ rotrFixed(x,13) ^ rotrFixed(x, 22))

 #define S1(x) (rotrFixed(x, 6) ^ rotrFixed(x,11) ^ rotrFixed(x, 25))

 #define s0(x) (rotrFixed(x, 7) ^ rotrFixed(x,18) ^ (x >> 3))

 #define s1(x) (rotrFixed(x,17) ^ rotrFixed(x,19) ^ (x >> 10))

 

 #define blk0(i) (W[i] = data[i])

 #define blk2(i) (W[i&15] += s1(W[(i-2)&15]) + W[(i-7)&15] + s0(W[(i-15)&15]))

 

 #define Ch(x,y,z) (z^(x&(y^z)))

 #define Maj(x,y,z) ((x&y)|(z&(x|y)))

 

 #define a(i) T[(0-(i))&7]

 #define b(i) T[(1-(i))&7]

 #define c(i) T[(2-(i))&7]

 #define d(i) T[(3-(i))&7]

 #define e(i) T[(4-(i))&7]

 #define f(i) T[(5-(i))&7]

 #define g(i) T[(6-(i))&7]

 #define h(i) T[(7-(i))&7]

 

 

 #ifdef _SHA256_UNROLL2

 

 #define R(a,b,c,d,e,f,g,h, i) h += S1(e) + Ch(e,f,g) + K[i+j] + (j?blk2(i):blk0(i));\

   d += h; h += S0(a) + Maj(a, b, c)

 

 #define RX_8(i) \

   R(a,b,c,d,e,f,g,h, i); \

   R(h,a,b,c,d,e,f,g, i+1); \

   R(g,h,a,b,c,d,e,f, i+2); \

   R(f,g,h,a,b,c,d,e, i+3); \

   R(e,f,g,h,a,b,c,d, i+4); \

   R(d,e,f,g,h,a,b,c, i+5); \

   R(c,d,e,f,g,h,a,b, i+6); \

   R(b,c,d,e,f,g,h,a, i+7)

 

 #else

 

 #define R(i) h(i) += S1(e(i)) + Ch(e(i),f(i),g(i)) + K[i+j] + (j?blk2(i):blk0(i));\

   d(i) += h(i); h(i) += S0(a(i)) + Maj(a(i), b(i), c(i))

 

 #ifdef _SHA256_UNROLL

 

 #define RX_8(i) R(i+0); R(i+1); R(i+2); R(i+3); R(i+4); R(i+5); R(i+6); R(i+7);

 

 #endif

 

 #endif

 

 const UInt32 K[64] = {

   0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,

   0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,

   0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,

   0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,

   0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,

   0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,

   0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,

   0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,

   0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,

   0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,

   0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,

   0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,

   0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,

   0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,

   0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,

   0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2

 };

 

 static void Sha256_Transform(UInt32 *state, const UInt32 *data)

 {

   UInt32 W[16];

   unsigned j;

   #ifdef _SHA256_UNROLL2

   UInt32 a,b,c,d,e,f,g,h;

   a = state[0];

   b = state[1];

   c = state[2];

   d = state[3];

   e = state[4];

   f = state[5];

   g = state[6];

   h = state[7];

   #else

   UInt32 T[8];

   for (j = 0; j < 8; j++)

     T[j] = state[j];

   #endif

 

   for (j = 0; j < 64; j += 16)

   {

     #if defined(_SHA256_UNROLL) || defined(_SHA256_UNROLL2)

     RX_8(0); RX_8(8);

     #else

     unsigned i;

     for (i = 0; i < 16; i++) { R(i); }

     #endif

   }

 

   #ifdef _SHA256_UNROLL2

   state[0] += a;

   state[1] += b;

   state[2] += c;

   state[3] += d;

   state[4] += e;

   state[5] += f;

   state[6] += g;

   state[7] += h;

   #else

   for (j = 0; j < 8; j++)

     state[j] += T[j];

   #endif

   

   /* Wipe variables */

   /* memset(W, 0, sizeof(W)); */

   /* memset(T, 0, sizeof(T)); */

 }

 

 #undef S0

 #undef S1

 #undef s0

 #undef s1

 

 static void Sha256_WriteByteBlock(CSha256 *p)

 {

   UInt32 data32[16];

   unsigned i;

   for (i = 0; i < 16; i++)

     data32[i] =

       ((UInt32)(p->buffer[i * 4    ]) << 24) +

       ((UInt32)(p->buffer[i * 4 + 1]) << 16) +

       ((UInt32)(p->buffer[i * 4 + 2]) <<  8) +

       ((UInt32)(p->buffer[i * 4 + 3]));

   Sha256_Transform(p->state, data32);

 }

 

 void Sha256_Update(CSha256 *p, const Byte *data, size_t size)

 {

   UInt32 curBufferPos = (UInt32)p->count & 0x3F;

   while (size > 0)

   {

     p->buffer[curBufferPos++] = *data++;

     p->count++;

     size--;

     if (curBufferPos == 64)

     {

       curBufferPos = 0;

       Sha256_WriteByteBlock(p);

     }

   }

 }

 

 void Sha256_Final(CSha256 *p, Byte *digest)

 {

   UInt64 lenInBits = (p->count << 3);

   UInt32 curBufferPos = (UInt32)p->count & 0x3F;

   unsigned i;

   p->buffer[curBufferPos++] = 0x80;

   while (curBufferPos != (64 - 8))

   {

     curBufferPos &= 0x3F;

     if (curBufferPos == 0)

       Sha256_WriteByteBlock(p);

     p->buffer[curBufferPos++] = 0;

   }

   for (i = 0; i < 8; i++)

   {

     p->buffer[curBufferPos++] = (Byte)(lenInBits >> 56);

     lenInBits <<= 8;

   }

   Sha256_WriteByteBlock(p);

 

   for (i = 0; i < 8; i++)

   {

     *digest++ = (Byte)((p->state[i] >> 24) & 0xFF);

     *digest++ = (Byte)((p->state[i] >> 16) & 0xFF);

     *digest++ = (Byte)((p->state[i] >> 8) & 0xFF);

     *digest++ = (Byte)((p->state[i]) & 0xFF);

   }

   Sha256_Init(p);

 }