```
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// WjCryptLib_Sha256
//
// Implementation of SHA256 hash function.
// Original author: Tom St Denis, tomstdenis@gmail.com, http://libtom.org
// Modified by WaterJuice retaining Public Domain license.
//
// This is free and unencumbered software released into the public domain - June 2013 waterjuice.org
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// IMPORTS
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#include "WjCryptLib_Sha256.h"
#include <memory.h>
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// MACROS
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#define ror(value, bits) (((value) >> (bits)) | ((value) << (32 - (bits))))
#define MIN(x, y) ( ((x)<(y))?(x):(y) )
#define STORE32H(x, y) \
{ (y)[0] = (uint8_t)(((x)>>24)&255); (y)[1] = (uint8_t)(((x)>>16)&255); \
(y)[2] = (uint8_t)(((x)>>8)&255); (y)[3] = (uint8_t)((x)&255); }
#define LOAD32H(x, y) \
{ x = ((uint32_t)((y)[0] & 255)<<24) | \
((uint32_t)((y)[1] & 255)<<16) | \
((uint32_t)((y)[2] & 255)<<8) | \
((uint32_t)((y)[3] & 255)); }
#define STORE64H(x, y) \
{ (y)[0] = (uint8_t)(((x)>>56)&255); (y)[1] = (uint8_t)(((x)>>48)&255); \
(y)[2] = (uint8_t)(((x)>>40)&255); (y)[3] = (uint8_t)(((x)>>32)&255); \
(y)[4] = (uint8_t)(((x)>>24)&255); (y)[5] = (uint8_t)(((x)>>16)&255); \
(y)[6] = (uint8_t)(((x)>>8)&255); (y)[7] = (uint8_t)((x)&255); }
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// CONSTANTS
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// The K array
static const uint32_t K[64] = {
0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, 0x3956c25bUL,
0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, 0xd807aa98UL, 0x12835b01UL,
0x243185beUL, 0x550c7dc3UL, 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL,
0xc19bf174UL, 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, 0x983e5152UL,
0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, 0xc6e00bf3UL, 0xd5a79147UL,
0x06ca6351UL, 0x14292967UL, 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL,
0x53380d13UL, 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, 0xd192e819UL,
0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, 0x19a4c116UL, 0x1e376c08UL,
0x2748774cUL, 0x34b0bcb5UL, 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL,
0x682e6ff3UL, 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
};
#define BLOCK_SIZE 64
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// INTERNAL FUNCTIONS
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Various logical functions
#define Ch( x, y, z ) (z ^ (x & (y ^ z)))
#define Maj( x, y, z ) (((x | y) & z) | (x & y))
#define S( x, n ) ror((x),(n))
#define R( x, n ) (((x)&0xFFFFFFFFUL)>>(n))
#define Sigma0( x ) (S(x, 2) ^ S(x, 13) ^ S(x, 22))
#define Sigma1( x ) (S(x, 6) ^ S(x, 11) ^ S(x, 25))
#define Gamma0( x ) (S(x, 7) ^ S(x, 18) ^ R(x, 3))
#define Gamma1( x ) (S(x, 17) ^ S(x, 19) ^ R(x, 10))
#define Sha256Round( a, b, c, d, e, f, g, h, i ) \
t0 = h + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
t1 = Sigma0(a) + Maj(a, b, c); \
d += t0; \
h = t0 + t1;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// TransformFunction
//
// Compress 512-bits
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
static
void
TransformFunction
(
Sha256Context* Context,
uint8_t const* Buffer
)
{
uint32_t S[8];
uint32_t W[64];
uint32_t t0;
uint32_t t1;
uint32_t t;
int i;
// Copy state into S
for( i=0; i<8; i++ )
{
S[i] = Context->state[i];
}
// Copy the state into 512-bits into W[0..15]
for( i=0; i<16; i++ )
{
LOAD32H( W[i], Buffer + (4*i) );
}
// Fill W[16..63]
for( i=16; i<64; i++ )
{
W[i] = Gamma1( W[i-2]) + W[i-7] + Gamma0( W[i-15] ) + W[i-16];
}
// Compress
for( i=0; i<64; i++ )
{
Sha256Round( S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], i );
t = S[7];
S[7] = S[6];
S[6] = S[5];
S[5] = S[4];
S[4] = S[3];
S[3] = S[2];
S[2] = S[1];
S[1] = S[0];
S[0] = t;
}
// Feedback
for( i=0; i<8; i++ )
{
Context->state[i] = Context->state[i] + S[i];
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// PUBLIC FUNCTIONS
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Sha256Initialise
//
// Initialises a SHA256 Context. Use this to initialise/reset a context.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
Sha256Initialise
(
Sha256Context* Context // [out]
)
{
Context->curlen = 0;
Context->length = 0;
Context->state[0] = 0x6A09E667UL;
Context->state[1] = 0xBB67AE85UL;
Context->state[2] = 0x3C6EF372UL;
Context->state[3] = 0xA54FF53AUL;
Context->state[4] = 0x510E527FUL;
Context->state[5] = 0x9B05688CUL;
Context->state[6] = 0x1F83D9ABUL;
Context->state[7] = 0x5BE0CD19UL;
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Sha256Update
//
// Adds data to the SHA256 context. This will process the data and update the internal state of the context. Keep on
// calling this function until all the data has been added. Then call Sha256Finalise to calculate the hash.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
Sha256Update
(
Sha256Context* Context, // [in out]
void const* Buffer, // [in]
uint32_t BufferSize // [in]
)
{
uint32_t n;
if( Context->curlen > sizeof(Context->buf) )
{
return;
}
while( BufferSize > 0 )
{
if( Context->curlen == 0 && BufferSize >= BLOCK_SIZE )
{
TransformFunction( Context, (uint8_t*)Buffer );
Context->length += BLOCK_SIZE * 8;
Buffer = (uint8_t*)Buffer + BLOCK_SIZE;
BufferSize -= BLOCK_SIZE;
}
else
{
n = MIN( BufferSize, (BLOCK_SIZE - Context->curlen) );
memcpy( Context->buf + Context->curlen, Buffer, (size_t)n );
Context->curlen += n;
Buffer = (uint8_t*)Buffer + n;
BufferSize -= n;
if( Context->curlen == BLOCK_SIZE )
{
TransformFunction( Context, Context->buf );
Context->length += 8*BLOCK_SIZE;
Context->curlen = 0;
}
}
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Sha256Finalise
//
// Performs the final calculation of the hash and returns the digest (32 byte buffer containing 256bit hash). After
// calling this, Sha256Initialised must be used to reuse the context.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
Sha256Finalise
(
Sha256Context* Context, // [in out]
SHA256_HASH* Digest // [out]
)
{
int i;
if( Context->curlen >= sizeof(Context->buf) )
{
return;
}
// Increase the length of the message
Context->length += Context->curlen * 8;
// Append the '1' bit
Context->buf[Context->curlen++] = (uint8_t)0x80;
// if the length is currently above 56 bytes we append zeros
// then compress. Then we can fall back to padding zeros and length
// encoding like normal.
if( Context->curlen > 56 )
{
while( Context->curlen < 64 )
{
Context->buf[Context->curlen++] = (uint8_t)0;
}
TransformFunction(Context, Context->buf);
Context->curlen = 0;
}
// Pad up to 56 bytes of zeroes
while( Context->curlen < 56 )
{
Context->buf[Context->curlen++] = (uint8_t)0;
}
// Store length
STORE64H( Context->length, Context->buf+56 );
TransformFunction( Context, Context->buf );
// Copy output
for( i=0; i<8; i++ )
{
STORE32H( Context->state[i], Digest->bytes+(4*i) );
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Sha256Calculate
//
// Combines Sha256Initialise, Sha256Update, and Sha256Finalise into one function. Calculates the SHA256 hash of the
// buffer.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
Sha256Calculate
(
void const* Buffer, // [in]
uint32_t BufferSize, // [in]
SHA256_HASH* Digest // [in]
)
{
Sha256Context context;
Sha256Initialise( &context );
Sha256Update( &context, Buffer, BufferSize );
Sha256Finalise( &context, Digest );
}
```
