File content as of revision 2:473bac39ae7c:

#include "SHA2_32.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

static const uint32_t K[] =
{
    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 uint32_t rotLeft(uint32_t w, uint8_t n)
{
    return (w << n) | (w >> (32-n));
}

static uint32_t rotRight(uint32_t w, uint8_t n)
{
    return rotLeft(w,32-n);
}

static uint32_t CH(uint32_t x, uint32_t y, uint32_t z)
{
    return (x & y) ^ ((~x) & z);
}

static uint32_t MAJ(uint32_t x, uint32_t y, uint32_t z)
{
    return (x & y) ^ (x & z) ^ (y & z);
}

static uint32_t BSIG0(uint32_t x)
{
    return rotRight(x,2) ^ rotRight(x,13) ^ rotRight(x,22);
}

static uint32_t BSIG1(uint32_t x)
{
    return rotRight(x,6) ^ rotRight(x,11) ^ rotRight(x,25);
}

static uint32_t SSIG0(uint32_t x)
{
    return rotRight(x,7) ^ rotRight(x,18) ^ (x >> 3);
}
 
static uint32_t SSIG1(uint32_t x)
{
    return rotRight(x,17) ^ rotRight(x,19) ^ (x >> 10);
}


static const uint32_t H[] =
{
    // SHA-224
    0xc1059ed8, 0x367cd507, 0x3070dd17, 0xf70e5939,
    0xffc00b31, 0x68581511, 0x64f98fa7, 0xbefa4fa4,
    
    // SHA-256      
    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
    0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
};

SHA2_32::SHA2_32(SHA_32_TYPE t):
type(t),
totalBufferLength(0),
bufferLength(0)
{
    switch(type)
    {
        case SHA_224:
            h0 = H[0];
            h1 = H[1];
            h2 = H[2];
            h3 = H[3];
            h4 = H[4];
            h5 = H[5];
            h6 = H[6];
            h7 = H[7];
        break;
        
        case SHA_256:
            h0 = H[8];
            h1 = H[9];
            h2 = H[10];
            h3 = H[11];
            h4 = H[12];
            h5 = H[13];
            h6 = H[14];
            h7 = H[15];     
        break;
    }
}

void SHA2_32::add(uint8_t *in, uint32_t length)
{
    if(length < 64-bufferLength)
    {
        memcpy(&buffer[bufferLength], in, length);
        bufferLength += length;
        totalBufferLength += length;
        return;
    }
    int offset = 64-bufferLength;
    memcpy(&buffer[bufferLength], in, offset);
    computeBlock(&h0,&h1,&h2,&h3,&h4,&h5,&h6,&h7,buffer);
    while(length-offset > 64)
    {
        memcpy(buffer, &in[offset], 64);
        computeBlock(&h0,&h1,&h2,&h3,&h4,&h5,&h6,&h7,buffer);
        offset += 64;
    }
    if(offset > length)
        offset -= 64;
    bufferLength = length - offset;
    memcpy(buffer, &in[offset], bufferLength);
    totalBufferLength += length;
}

void SHA2_32::computeDigest(uint8_t *digest)
{
    uint16_t padding;
    if(totalBufferLength % 64 < 56)
        padding = 56 - (totalBufferLength % 64);
    else
        padding = 56 + (64 - (totalBufferLength % 64));
    uint8_t val = 0x80;
    add(&val, 1);
    val = 0;
    for(int i = 0; i < padding-1; ++i)
        add(&val,1);
    totalBufferLength -= padding;
    uint64_t lengthBit = totalBufferLength * 8;
    uint32_t lengthBitLow = lengthBit;
    uint32_t lengthBitHigh = lengthBit >> 32;
    uint8_t tmp[4];
    tmp[0] = lengthBitHigh >> 24;
    tmp[1] = lengthBitHigh >> 16;
    tmp[2] = lengthBitHigh >> 8;
    tmp[3] = lengthBitHigh;
    add(tmp, 4);
    tmp[0] = lengthBitLow >> 24;
    tmp[1] = lengthBitLow >> 16;
    tmp[2] = lengthBitLow >> 8;
    tmp[3] = lengthBitLow;
    add(tmp, 4);

    digest[0] = h0 >> 24;
    digest[1] = h0 >> 16;
    digest[2] = h0 >> 8;
    digest[3] = h0;
    digest[4] = h1 >> 24;
    digest[5] = h1 >> 16;
    digest[6] = h1 >> 8;
    digest[7] = h1;
    digest[8] = h2 >> 24;
    digest[9] = h2 >> 16;
    digest[10] = h2 >> 8;
    digest[11] = h2;
    digest[12] = h3 >> 24;
    digest[13] = h3 >> 16;
    digest[14] = h3 >> 8;
    digest[15] = h3;
    digest[16] = h4 >> 24;
    digest[17] = h4 >> 16;
    digest[18] = h4 >> 8;
    digest[19] = h4;
    digest[20] = h5 >> 24;
    digest[21] = h5 >> 16;
    digest[22] = h5 >> 8;
    digest[23] = h5;
    digest[24] = h6 >> 24;
    digest[25] = h6 >> 16;
    digest[26] = h6 >> 8;
    digest[27] = h6;

    if(type == SHA_256)
    {
        digest[28] = h7 >> 24;
        digest[29] = h7 >> 16;
        digest[30] = h7 >> 8;
        digest[31] = h7;
    }
    
    // reset state
    switch(type)
    {
        case SHA_224:
            h0 = H[0];
            h1 = H[1];
            h2 = H[2];
            h3 = H[3];
            h4 = H[4];
            h5 = H[5];
            h6 = H[6];
            h7 = H[7];
        break;
        
        case SHA_256:
            h0 = H[8];
            h1 = H[9];
            h2 = H[10];
            h3 = H[11];
            h4 = H[12];
            h5 = H[13];
            h6 = H[14];
            h7 = H[15];     
        break;
    }
    totalBufferLength = 0;
    bufferLength = 0;
}

void SHA2_32::computeBlock(uint32_t *h02, 
                        uint32_t *h12, 
                        uint32_t *h22, 
                        uint32_t *h32, 
                        uint32_t *h42, 
                        uint32_t *h52, 
                        uint32_t *h62,
                        uint32_t *h72,
                        uint8_t *buffer)
{
    uint32_t w[64];
    for(int t = 0; t < 16; ++t)
    {
        w[t] = (buffer[t*4] << 24) | (buffer[t*4+1] << 16) | (buffer[t*4+2] << 8) | buffer[t*4+3]; 
    }
    for(int t = 16; t < 64; ++t)
        w[t] = SSIG1(w[t-2]) + w[t-7] + SSIG0(w[t-15]) + w[t-16];
    
     uint32_t a = *h02, b = *h12, c = *h22, d = *h32, e = *h42, f = *h52, g = *h62, h = *h72;
    for(int t = 0; t < 64; ++t)
    {
        uint32_t T1 = h + BSIG1(e) + CH(e,f,g) + K[t] + w[t];
        uint32_t T2 = BSIG0(a) + MAJ(a,b,c);
        h = g;
        g = f;
        f = e;
        e = d + T1;
        d = c;
        c = b;
        b = a;
        a = T1 + T2;
    }
    
    *h02 += a;
    *h12 += b;
    *h22 += c;
    *h32 += d;
    *h42 += e;
    *h52 += f;
    *h62 += g;
    *h72 += h;
}

void SHA2_32::computeDigest(SHA_32_TYPE type, uint8_t *digest, uint8_t *in, uint32_t length)
{
    uint32_t h0 = H[type*8], h1 = H[type*8+1], h2 = H[type*8+2], h3 = H[type*8+3];
    uint32_t h4 = H[type*8+4], h5 = H[type*8+5], h6 = H[type*8+6], h7 = H[type*8+7];
    int offset = 0;
    while(length - offset >= 64)
    {
        computeBlock(&h0, &h1, &h2, &h3, &h4, &h5, &h6, &h7, &in[offset]);
        offset += 64;
    }
    uint8_t bufferLength = length-offset;
    uint8_t buffer[64];
    memcpy(buffer, &in[offset],bufferLength); 
    uint16_t padding;
    if(length % 64 < 56)
        padding = 56 - (length % 64);
    else
        padding = 56 + (64 - (length % 64));
    buffer[bufferLength] = 0x80;
    bufferLength++;
    padding--;
    while(padding > 0)
    {
        if(bufferLength == 64)
        {
            computeBlock(&h0, &h1, &h2, &h3, &h4, &h5, &h6, &h7, buffer);
            bufferLength = 0;
        }
        buffer[bufferLength] = 0;
        bufferLength++;
        padding--;
    }
    uint64_t lengthBit = length * 8;
    uint32_t lengthBitLow = lengthBit;
    uint32_t lengthBitHigh = lengthBit >> 32;
    lengthBitLow = __rev(lengthBitLow);
    memcpy(&buffer[60], &lengthBitLow, 4);
    lengthBitHigh = __rev(lengthBitHigh);
    memcpy(&buffer[56], &lengthBitHigh, 4);    
    computeBlock(&h0, &h1, &h2, &h3, &h4, &h5, &h6, &h7, buffer);

    h0 = __rev(h0);
    h1 = __rev(h1);
    h2 = __rev(h2);
    h3 = __rev(h3);
    h4 = __rev(h4);
    h5 = __rev(h5);
    h6 = __rev(h6);

    memcpy(digest, &h0, 4);
    memcpy(&digest[4], &h1, 4);
    memcpy(&digest[8], &h2, 4);
    memcpy(&digest[12], &h3, 4);
    memcpy(&digest[16], &h4, 4);
    memcpy(&digest[20], &h5, 4);
    memcpy(&digest[24], &h6, 4);


    if(type == SHA_256)
    {
        h7 = __rev(h7);
        memcpy(&digest[28], &h7, 4);
    }
}