sha2.c

SHA-2 的代码实现

	j++


#else /* BYTE_ORDER == LITTLE_ENDIAN */

#define ROUND256_0_TO_15(a,b,c,d,e,f,g,h)	\
	T1 = (h) + Sigma1_256(e) + Ch((e), (f), (g)) + \
	     K256[j] + (W256[j] = *data++); \
	(d) += T1; \
	(h) = T1 + Sigma0_256(a) + Maj((a), (b), (c)); \
	j++

#endif /* BYTE_ORDER == LITTLE_ENDIAN */

#define ROUND256(a,b,c,d,e,f,g,h)	\
	s0 = W256[(j+1)&0x0f]; \
	s0 = sigma0_256(s0); \
	s1 = W256[(j+14)&0x0f]; \
	s1 = sigma1_256(s1); \
	T1 = (h) + Sigma1_256(e) + Ch((e), (f), (g)) + K256[j] + \
	     (W256[j&0x0f] += s1 + W256[(j+9)&0x0f] + s0); \
	(d) += T1; \
	(h) = T1 + Sigma0_256(a) + Maj((a), (b), (c)); \
	j++

void SHA256_Transform(SHA256_CTX* context, const sha2_word32* data) {
	sha2_word32	a, b, c, d, e, f, g, h, s0, s1;
	sha2_word32	T1, *W256;
	int		j;

	W256 = (sha2_word32*)context->buffer;

	/* Initialize registers with the prev. intermediate value */
	a = context->state[0];
	b = context->state[1];
	c = context->state[2];
	d = context->state[3];
	e = context->state[4];
	f = context->state[5];
	g = context->state[6];
	h = context->state[7];

	j = 0;
	do {
		/* Rounds 0 to 15 (unrolled): */
		ROUND256_0_TO_15(a,b,c,d,e,f,g,h);
		ROUND256_0_TO_15(h,a,b,c,d,e,f,g);
		ROUND256_0_TO_15(g,h,a,b,c,d,e,f);
		ROUND256_0_TO_15(f,g,h,a,b,c,d,e);
		ROUND256_0_TO_15(e,f,g,h,a,b,c,d);
		ROUND256_0_TO_15(d,e,f,g,h,a,b,c);
		ROUND256_0_TO_15(c,d,e,f,g,h,a,b);
		ROUND256_0_TO_15(b,c,d,e,f,g,h,a);
	} while (j < 16);

	/* Now for the remaining rounds to 64: */
	do {
		ROUND256(a,b,c,d,e,f,g,h);
		ROUND256(h,a,b,c,d,e,f,g);
		ROUND256(g,h,a,b,c,d,e,f);
		ROUND256(f,g,h,a,b,c,d,e);
		ROUND256(e,f,g,h,a,b,c,d);
		ROUND256(d,e,f,g,h,a,b,c);
		ROUND256(c,d,e,f,g,h,a,b);
		ROUND256(b,c,d,e,f,g,h,a);
	} while (j < 64);

	/* Compute the current intermediate hash value */
	context->state[0] += a;
	context->state[1] += b;
	context->state[2] += c;
	context->state[3] += d;
	context->state[4] += e;
	context->state[5] += f;
	context->state[6] += g;
	context->state[7] += h;

	/* Clean up */
	a = b = c = d = e = f = g = h = T1 = 0;
}

#else /* SHA2_UNROLL_TRANSFORM */

void SHA256_Transform(SHA256_CTX* context, const sha2_word32* data) {
	sha2_word32	a, b, c, d, e, f, g, h, s0, s1;
	sha2_word32	T1, T2, *W256;
	int		j;

	W256 = (sha2_word32*)context->buffer;

	/* Initialize registers with the prev. intermediate value */
	a = context->state[0];
	b = context->state[1];
	c = context->state[2];
	d = context->state[3];
	e = context->state[4];
	f = context->state[5];
	g = context->state[6];
	h = context->state[7];

	j = 0;
	do {
#if BYTE_ORDER == LITTLE_ENDIAN
		/* Copy data while converting to host byte order */
		REVERSE32(*data++,W256[j]);
		/* Apply the SHA-256 compression function to update a..h */
		T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + W256[j];
#else /* BYTE_ORDER == LITTLE_ENDIAN */
		/* Apply the SHA-256 compression function to update a..h with copy */
		T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + (W256[j] = *data++);
#endif /* BYTE_ORDER == LITTLE_ENDIAN */
		T2 = Sigma0_256(a) + Maj(a, b, c);
		h = g;
		g = f;
		f = e;
		e = d + T1;
		d = c;
		c = b;
		b = a;
		a = T1 + T2;

		j++;
	} while (j < 16);

	do {
		/* Part of the message block expansion: */
		s0 = W256[(j+1)&0x0f];
		s0 = sigma0_256(s0);
		s1 = W256[(j+14)&0x0f];	
		s1 = sigma1_256(s1);

		/* Apply the SHA-256 compression function to update a..h */
		T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + 
		     (W256[j&0x0f] += s1 + W256[(j+9)&0x0f] + s0);
		T2 = Sigma0_256(a) + Maj(a, b, c);
		h = g;
		g = f;
		f = e;
		e = d + T1;
		d = c;
		c = b;
		b = a;
		a = T1 + T2;

		j++;
	} while (j < 64);

	/* Compute the current intermediate hash value */
	context->state[0] += a;
	context->state[1] += b;
	context->state[2] += c;
	context->state[3] += d;
	context->state[4] += e;
	context->state[5] += f;
	context->state[6] += g;
	context->state[7] += h;

	/* Clean up */
	a = b = c = d = e = f = g = h = T1 = T2 = 0;
}

#endif /* SHA2_UNROLL_TRANSFORM */

void SHA256_Update(SHA256_CTX* context, const sha2_byte *data, size_t len) {
	unsigned int	freespace, usedspace;

	if (len == 0) {
		/* Calling with no data is valid - we do nothing */
		return;
	}

	/* Sanity check: */
	assert(context != (SHA256_CTX*)0 && data != (sha2_byte*)0);

	usedspace = (context->bitcount >> 3) % SHA256_BLOCK_LENGTH;
	if (usedspace > 0) {
		/* Calculate how much free space is available in the buffer */
		freespace = SHA256_BLOCK_LENGTH - usedspace;

		if (len >= freespace) {
			/* Fill the buffer completely and process it */
			MEMCPY_BCOPY(&context->buffer[usedspace], data, freespace);
			context->bitcount += freespace << 3;
			len -= freespace;
			data += freespace;
			SHA256_Transform(context, (sha2_word32*)context->buffer);
		} else {
			/* The buffer is not yet full */
			MEMCPY_BCOPY(&context->buffer[usedspace], data, len);
			context->bitcount += len << 3;
			/* Clean up: */
			usedspace = freespace = 0;
			return;
		}
	}
	while (len >= SHA256_BLOCK_LENGTH) {
		/* Process as many complete blocks as we can */
		SHA256_Transform(context, (sha2_word32*)data);
		context->bitcount += SHA256_BLOCK_LENGTH << 3;
		len -= SHA256_BLOCK_LENGTH;
		data += SHA256_BLOCK_LENGTH;
	}
	if (len > 0) {
		/* There's left-overs, so save 'em */
		MEMCPY_BCOPY(context->buffer, data, len);
		context->bitcount += len << 3;
	}
	/* Clean up: */
	usedspace = freespace = 0;
}

void SHA256_Final(sha2_byte digest[], SHA256_CTX* context) {
	sha2_word32	*d = (sha2_word32*)digest;
	unsigned int	usedspace;

	/* Sanity check: */
	assert(context != (SHA256_CTX*)0);

	/* If no digest buffer is passed, we don't bother doing this: */
	if (digest != (sha2_byte*)0) {
		usedspace = (context->bitcount >> 3) % SHA256_BLOCK_LENGTH;
#if BYTE_ORDER == LITTLE_ENDIAN
		/* Convert FROM host byte order */
		REVERSE64(context->bitcount,context->bitcount);
#endif
		if (usedspace > 0) {
			/* Begin padding with a 1 bit: */
			context->buffer[usedspace++] = 0x80;

			if (usedspace <= SHA256_SHORT_BLOCK_LENGTH) {
				/* Set-up for the last transform: */
				MEMSET_BZERO(&context->buffer[usedspace], SHA256_SHORT_BLOCK_LENGTH - usedspace);
			} else {
				if (usedspace < SHA256_BLOCK_LENGTH) {
					MEMSET_BZERO(&context->buffer[usedspace], SHA256_BLOCK_LENGTH - usedspace);
				}
				/* Do second-to-last transform: */
				SHA256_Transform(context, (sha2_word32*)context->buffer);

				/* And set-up for the last transform: */
				MEMSET_BZERO(context->buffer, SHA256_SHORT_BLOCK_LENGTH);
			}
		} else {
			/* Set-up for the last transform: */
			MEMSET_BZERO(context->buffer, SHA256_SHORT_BLOCK_LENGTH);

			/* Begin padding with a 1 bit: */
			*context->buffer = 0x80;
		}
		/* Set the bit count: */
		*(sha2_word64*)&context->buffer[SHA256_SHORT_BLOCK_LENGTH] = context->bitcount;

		/* Final transform: */
		SHA256_Transform(context, (sha2_word32*)context->buffer);

#if BYTE_ORDER == LITTLE_ENDIAN
		{
			/* Convert TO host byte order */
			int	j;
			for (j = 0; j < 8; j++) {
				REVERSE32(context->state[j],context->state[j]);
				*d++ = context->state[j];
			}
		}
#else
		MEMCPY_BCOPY(d, context->state, SHA256_DIGEST_LENGTH);
#endif
	}

	/* Clean up state data: */
	MEMSET_BZERO(context, sizeof(context));
	usedspace = 0;
}

char *SHA256_End(SHA256_CTX* context, char buffer[]) {
	sha2_byte	digest[SHA256_DIGEST_LENGTH], *d = digest;
	int		i;

	/* Sanity check: */
	assert(context != (SHA256_CTX*)0);

	if (buffer != (char*)0) {
		SHA256_Final(digest, context);

		for (i = 0; i < SHA256_DIGEST_LENGTH; i++) {
			*buffer++ = sha2_hex_digits[(*d & 0xf0) >> 4];
			*buffer++ = sha2_hex_digits[*d & 0x0f];
			d++;
		}
		*buffer = (char)0;
	} else {
		MEMSET_BZERO(context, sizeof(context));
	}
	MEMSET_BZERO(digest, SHA256_DIGEST_LENGTH);
	return buffer;
}

char* SHA256_Data(const sha2_byte* data, size_t len, char digest[SHA256_DIGEST_STRING_LENGTH]) {
	SHA256_CTX	context;

	SHA256_Init(&context);
	SHA256_Update(&context, data, len);
	return SHA256_End(&context, digest);
}


/*** SHA-512: *********************************************************/
void SHA512_Init(SHA512_CTX* context) {
	if (context == (SHA512_CTX*)0) {
		return;
	}
	MEMCPY_BCOPY(context->state, sha512_initial_hash_value, SHA512_DIGEST_LENGTH);
	MEMSET_BZERO(context->buffer, SHA512_BLOCK_LENGTH);
	context->bitcount[0] = context->bitcount[1] =  0;
}

#ifdef SHA2_UNROLL_TRANSFORM

/* Unrolled SHA-512 round macros: */
#if BYTE_ORDER == LITTLE_ENDIAN

#define ROUND512_0_TO_15(a,b,c,d,e,f,g,h)	\
	REVERSE64(*data++, W512[j]); \
	T1 = (h) + Sigma1_512(e) + Ch((e), (f), (g)) + \
             K512[j] + W512[j]; \
	(d) += T1, \
	(h) = T1 + Sigma0_512(a) + Maj((a), (b), (c)), \
	j++


#else /* BYTE_ORDER == LITTLE_ENDIAN */

#define ROUND512_0_TO_15(a,b,c,d,e,f,g,h)	\
	T1 = (h) + Sigma1_512(e) + Ch((e), (f), (g)) + \
             K512[j] + (W512[j] = *data++); \
	(d) += T1; \
	(h) = T1 + Sigma0_512(a) + Maj((a), (b), (c)); \
	j++

#endif /* BYTE_ORDER == LITTLE_ENDIAN */

#define ROUND512(a,b,c,d,e,f,g,h)	\
	s0 = W512[(j+1)&0x0f]; \
	s0 = sigma0_512(s0); \
	s1 = W512[(j+14)&0x0f]; \
	s1 = sigma1_512(s1); \
	T1 = (h) + Sigma1_512(e) + Ch((e), (f), (g)) + K512[j] + \
             (W512[j&0x0f] += s1 + W512[(j+9)&0x0f] + s0); \
	(d) += T1; \
	(h) = T1 + Sigma0_512(a) + Maj((a), (b), (c)); \
	j++

void SHA512_Transform(SHA512_CTX* context, const sha2_word64* data) {
	sha2_word64	a, b, c, d, e, f, g, h, s0, s1;
	sha2_word64	T1, *W512 = (sha2_word64*)context->buffer;
	int		j;