sha2.cpp

计算文件hash值的源代码

    
    /* the following 32-bit length fields are assembled in the      */
    /* wrong byte order on little endian machines but this is       */
    /* corrected later since they are only ever used as 32-bit      */
    /* word values.                                                 */

    ctx->wbuf[14] = (ctx->count[1] << 3) | (ctx->count[0] >> 29);
    ctx->wbuf[15] = ctx->count[0] << 3;

    sha256_compile(ctx);

    /* extract the hash value as bytes in case the hash buffer is   */
    /* mislaigned for 32-bit words                                  */
    for(i = 0; i < SHA256_DIGEST_SIZE; ++i)
        hval[i] = (unsigned char)(ctx->hash[i >> 2] >> 8 * (~i & 3));
}

void sha256(unsigned char hval[], const unsigned char data[], unsigned long len) 
{   sha256_ctx  cx[1];
    
    sha256_begin(cx); sha256_hash(data, len, cx); sha256_end(hval, cx);
}

#endif

#if defined(SHA_2) || defined(SHA_384) || defined(SHA_512)

#define SHA512_MASK (SHA512_BLOCK_SIZE - 1)

#define rotr64(x,n)   (((x) >> n) | ((x) << (64 - n)))

#if !defined(bswap_64)
#define bswap_64(x) (((sha2_64t)(bswap_32((sha2_32t)(x)))) << 32 | bswap_32((sha2_32t)((x) >> 32)))
#endif

#if defined(SWAP_BYTES)
#define	bsw_64(p,n)	{ int _i = (n);	while(_i--) p[_i] = bswap_64(p[_i]); }
#else
#define	bsw_64(p,n)	
#endif

/* SHA512 mixing function definitions   */

#define s512_0(x) (rotr64((x), 28) ^ rotr64((x), 34) ^ rotr64((x), 39)) 
#define s512_1(x) (rotr64((x), 14) ^ rotr64((x), 18) ^ rotr64((x), 41)) 
#define g512_0(x) (rotr64((x),  1) ^ rotr64((x),  8) ^ ((x) >>  7)) 
#define g512_1(x) (rotr64((x), 19) ^ rotr64((x), 61) ^ ((x) >>  6)) 

/* rotated SHA512 round definition. Rather than swapping variables as in    */
/* FIPS-180, different variables are 'rotated' on each round, returning     */
/* to their starting positions every eight rounds                           */

#define h5(i) ctx->wbuf[i & 15] += \
    g512_1(ctx->wbuf[(i + 14) & 15]) + ctx->wbuf[(i + 9) & 15] + g512_0(ctx->wbuf[(i + 1) & 15])

#define h5_cycle(i,j)  \
    v[(7 - i) & 7] += (j ? h5(i) : ctx->wbuf[i & 15]) + k512[i + j] \
        + s512_1(v[(4 - i) & 7]) + ch(v[(4 - i) & 7], v[(5 - i) & 7], v[(6 - i) & 7]); \
    v[(3 - i) & 7] += v[(7 - i) & 7]; \
    v[(7 - i) & 7] += s512_0(v[(0 - i) & 7]) + maj(v[(0 - i) & 7], v[(1 - i) & 7], v[(2 - i) & 7])

/* SHA384/SHA512 mixing data    */

const sha2_64t  k512[80] = 
{
    n_u64(428a2f98d728ae22), n_u64(7137449123ef65cd), 
    n_u64(b5c0fbcfec4d3b2f), n_u64(e9b5dba58189dbbc),
    n_u64(3956c25bf348b538), n_u64(59f111f1b605d019),
    n_u64(923f82a4af194f9b), n_u64(ab1c5ed5da6d8118),
    n_u64(d807aa98a3030242), n_u64(12835b0145706fbe),
    n_u64(243185be4ee4b28c), n_u64(550c7dc3d5ffb4e2),
    n_u64(72be5d74f27b896f), n_u64(80deb1fe3b1696b1),
    n_u64(9bdc06a725c71235), n_u64(c19bf174cf692694),
    n_u64(e49b69c19ef14ad2), n_u64(efbe4786384f25e3),
    n_u64(0fc19dc68b8cd5b5), n_u64(240ca1cc77ac9c65),
    n_u64(2de92c6f592b0275), n_u64(4a7484aa6ea6e483),
    n_u64(5cb0a9dcbd41fbd4), n_u64(76f988da831153b5),
    n_u64(983e5152ee66dfab), n_u64(a831c66d2db43210),
    n_u64(b00327c898fb213f), n_u64(bf597fc7beef0ee4),
    n_u64(c6e00bf33da88fc2), n_u64(d5a79147930aa725),
    n_u64(06ca6351e003826f), n_u64(142929670a0e6e70),
    n_u64(27b70a8546d22ffc), n_u64(2e1b21385c26c926),
    n_u64(4d2c6dfc5ac42aed), n_u64(53380d139d95b3df),
    n_u64(650a73548baf63de), n_u64(766a0abb3c77b2a8),
    n_u64(81c2c92e47edaee6), n_u64(92722c851482353b),
    n_u64(a2bfe8a14cf10364), n_u64(a81a664bbc423001),
    n_u64(c24b8b70d0f89791), n_u64(c76c51a30654be30),
    n_u64(d192e819d6ef5218), n_u64(d69906245565a910),
    n_u64(f40e35855771202a), n_u64(106aa07032bbd1b8),
    n_u64(19a4c116b8d2d0c8), n_u64(1e376c085141ab53),
    n_u64(2748774cdf8eeb99), n_u64(34b0bcb5e19b48a8),
    n_u64(391c0cb3c5c95a63), n_u64(4ed8aa4ae3418acb),
    n_u64(5b9cca4f7763e373), n_u64(682e6ff3d6b2b8a3),
    n_u64(748f82ee5defb2fc), n_u64(78a5636f43172f60),
    n_u64(84c87814a1f0ab72), n_u64(8cc702081a6439ec),
    n_u64(90befffa23631e28), n_u64(a4506cebde82bde9),
    n_u64(bef9a3f7b2c67915), n_u64(c67178f2e372532b),
    n_u64(ca273eceea26619c), n_u64(d186b8c721c0c207),
    n_u64(eada7dd6cde0eb1e), n_u64(f57d4f7fee6ed178),
    n_u64(06f067aa72176fba), n_u64(0a637dc5a2c898a6),
    n_u64(113f9804bef90dae), n_u64(1b710b35131c471b),
    n_u64(28db77f523047d84), n_u64(32caab7b40c72493),
    n_u64(3c9ebe0a15c9bebc), n_u64(431d67c49c100d4c),
    n_u64(4cc5d4becb3e42b6), n_u64(597f299cfc657e2a),
    n_u64(5fcb6fab3ad6faec), n_u64(6c44198c4a475817)
};

/* Compile 64 bytes of hash data into SHA384/SHA512 digest value  */

void sha512_compile(sha512_ctx ctx[1])
{   sha2_64t    v[8];
    sha2_32t    j;

    memcpy(v, ctx->hash, 8 * sizeof(sha2_64t));

    for(j = 0; j < 80; j += 16)
    {
        h5_cycle( 0, j); h5_cycle( 1, j); h5_cycle( 2, j); h5_cycle( 3, j);
        h5_cycle( 4, j); h5_cycle( 5, j); h5_cycle( 6, j); h5_cycle( 7, j);
        h5_cycle( 8, j); h5_cycle( 9, j); h5_cycle(10, j); h5_cycle(11, j);
        h5_cycle(12, j); h5_cycle(13, j); h5_cycle(14, j); h5_cycle(15, j);
    }

    ctx->hash[0] += v[0]; ctx->hash[1] += v[1]; ctx->hash[2] += v[2]; ctx->hash[3] += v[3];
    ctx->hash[4] += v[4]; ctx->hash[5] += v[5]; ctx->hash[6] += v[6]; ctx->hash[7] += v[7];
}

/* Compile 128 bytes of hash data into SHA256 digest value  */
/* NOTE: this routine assumes that the byte order in the    */
/* ctx->wbuf[] at this point is in such an order that low   */
/* address bytes in the ORIGINAL byte stream placed in this */
/* buffer will now go to the high end of words on BOTH big  */
/* and little endian systems                                */

void sha512_hash(const unsigned char data[], unsigned long len, sha512_ctx ctx[1])
{   sha2_32t pos = (sha2_32t)(ctx->count[0] & SHA512_MASK), 
             space = SHA512_BLOCK_SIZE - pos;
    const unsigned char *sp = data;

    if((ctx->count[0] += len) < len)
        ++(ctx->count[1]);

    while(len >= space)     /* tranfer whole blocks while possible  */
    {
        memcpy(((unsigned char*)ctx->wbuf) + pos, sp, space);
        sp += space; len -= space; space = SHA512_BLOCK_SIZE; pos = 0; 
		bsw_64(ctx->wbuf, SHA512_BLOCK_SIZE >> 3);        
        sha512_compile(ctx);
    }

    memcpy(((unsigned char*)ctx->wbuf) + pos, sp, len);
}

/* SHA384/512 Final padding and digest calculation  */

static sha2_64t  m2[8] =
{
    n_u64(0000000000000000), n_u64(ff00000000000000), 
    n_u64(ffff000000000000), n_u64(ffffff0000000000),
    n_u64(ffffffff00000000), n_u64(ffffffffff000000),
    n_u64(ffffffffffff0000), n_u64(ffffffffffffff00)
};

static sha2_64t  b2[8] =
{
    n_u64(8000000000000000), n_u64(0080000000000000), 
    n_u64(0000800000000000), n_u64(0000008000000000),
    n_u64(0000000080000000), n_u64(0000000000800000), 
    n_u64(0000000000008000), n_u64(0000000000000080)
};

static void sha_end(unsigned char hval[], sha512_ctx ctx[1], const unsigned int hlen)
{   sha2_32t    i = (sha2_32t)(ctx->count[0] & SHA512_MASK);

	bsw_64(ctx->wbuf, (i + 7) >> 3);

    /* bytes in the buffer are now in an order in which references  */
    /* to 64-bit words will put bytes with lower addresses into the */
    /* top of 64 bit words on BOTH big and little endian machines   */
    
    /* we now need to mask valid bytes and add the padding which is */
    /* a single 1 bit and as many zero bits as necessary.           */
    ctx->wbuf[i >> 3] = (ctx->wbuf[i >> 3] & m2[i & 7]) | b2[i & 7];

    /* we need 17 or more empty byte positions, one for the padding */
    /* byte (above) and sixteen for the length count.  If there is  */
    /* not enough space pad and empty the buffer                    */
    if(i > SHA512_BLOCK_SIZE - 17)
    {
        if(i < 120) ctx->wbuf[15] = 0;
        sha512_compile(ctx);
        i = 0;
    }
    else
        i = (i >> 3) + 1;

    while(i < 14)
        ctx->wbuf[i++] = 0;
    
    /* the following 64-bit length fields are assembled in the      */
    /* wrong byte order on little endian machines but this is       */
    /* corrected later since they are only ever used as 64-bit      */
    /* word values.                                                 */

    ctx->wbuf[14] = (ctx->count[1] << 3) | (ctx->count[0] >> 61);
    ctx->wbuf[15] = ctx->count[0] << 3;

    sha512_compile(ctx);

    /* extract the hash value as bytes in case the hash buffer is   */
    /* misaligned for 32-bit words                                  */
    for(i = 0; i < hlen; ++i)
        hval[i] = (unsigned char)(ctx->hash[i >> 3] >> 8 * (~i & 7));
}

#endif

#if defined(SHA_2) || defined(SHA_384)

/* SHA384 initialisation data   */

const sha2_64t  i384[80] = 
{
    n_u64(cbbb9d5dc1059ed8), n_u64(629a292a367cd507),
    n_u64(9159015a3070dd17), n_u64(152fecd8f70e5939),
    n_u64(67332667ffc00b31), n_u64(8eb44a8768581511),
    n_u64(db0c2e0d64f98fa7), n_u64(47b5481dbefa4fa4)
};

void sha384_begin(sha384_ctx ctx[1])
{
    ctx->count[0] = ctx->count[1] = 0;
    memcpy(ctx->hash, i384, 8 * sizeof(sha2_64t));
}

void sha384_end(unsigned char hval[], sha384_ctx ctx[1])
{
    sha_end(hval, ctx, SHA384_DIGEST_SIZE);
}

void sha384(unsigned char hval[], const unsigned char data[], unsigned long len)
{   sha384_ctx  cx[1];
    
    sha384_begin(cx); sha384_hash(data, len, cx); sha384_end(hval, cx);
}

#endif

#if defined(SHA_2) || defined(SHA_512)

/* SHA512 initialisation data   */

const sha2_64t  i512[80] = 
{
    n_u64(6a09e667f3bcc908), n_u64(bb67ae8584caa73b),
    n_u64(3c6ef372fe94f82b), n_u64(a54ff53a5f1d36f1),
    n_u64(510e527fade682d1), n_u64(9b05688c2b3e6c1f),
    n_u64(1f83d9abfb41bd6b), n_u64(5be0cd19137e2179)
};

void sha512_begin(sha512_ctx ctx[1])
{
    ctx->count[0] = ctx->count[1] = 0;
    memcpy(ctx->hash, i512, 8 * sizeof(sha2_64t));
}

void sha512_end(unsigned char hval[], sha512_ctx ctx[1])
{
    sha_end(hval, ctx, SHA512_DIGEST_SIZE);
}

void sha512(unsigned char hval[], const unsigned char data[], unsigned long len) 
{   sha512_ctx  cx[1];
    
    sha512_begin(cx); sha512_hash(data, len, cx); sha512_end(hval, cx);
}

#endif

#if defined(SHA_2)

#define CTX_256(x)  ((x)->uu->ctx256)
#define CTX_384(x)  ((x)->uu->ctx512)
#define CTX_512(x)  ((x)->uu->ctx512)

/* SHA2 initialisation */

int sha2_begin(unsigned long len, sha2_ctx ctx[1])
{   unsigned long   l = len;
    switch(len)
    {
        case 256:   l = len >> 3;
        case  32:   CTX_256(ctx)->count[0] = CTX_256(ctx)->count[1] = 0;
                    memcpy(CTX_256(ctx)->hash, i256, 32); break;
        case 384:   l = len >> 3;
        case  48:   CTX_384(ctx)->count[0] = CTX_384(ctx)->count[1] = 0;
                    memcpy(CTX_384(ctx)->hash, i384, 64); break;
        case 512:   l = len >> 3;
        case  64:   CTX_512(ctx)->count[0] = CTX_512(ctx)->count[1] = 0;
                    memcpy(CTX_512(ctx)->hash, i512, 64); break;
        default:    return SHA2_BAD;
    }
    
    ctx->sha2_len = l; return SHA2_GOOD;
}

void sha2_hash(const unsigned char data[], unsigned long len, sha2_ctx ctx[1])
{
    switch(ctx->sha2_len)
    {
        case 32: sha256_hash(data, len, CTX_256(ctx)); return;
        case 48: sha384_hash(data, len, CTX_384(ctx)); return;
        case 64: sha512_hash(data, len, CTX_512(ctx)); return;
    }
}

void sha2_end(unsigned char hval[], sha2_ctx ctx[1])
{
    switch(ctx->sha2_len)
    {
        case 32: sha256_end(hval, CTX_256(ctx)); return;
        case 48: sha_end(hval, CTX_384(ctx), SHA384_DIGEST_SIZE); return;
        case 64: sha_end(hval, CTX_512(ctx), SHA512_DIGEST_SIZE); return;
    }
}

int sha2(unsigned char hval[], unsigned long size,
                                const unsigned char data[], unsigned long len)
{   sha2_ctx    cx[1];

    if(sha2_begin(size, cx) == SHA2_GOOD)
    {
        sha2_hash(data, len, cx); sha2_end(hval, cx); return SHA2_GOOD;
    }
    else
        return SHA2_BAD;
}

#endif