sha1.cpp

/*
SHA-1 in C
By Steve Reid <steve@edmweb.com>
100% Public Domain

Test Vectors (from FIPS PUB 180-1)
"abc"
  A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D
"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
  84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1
A million repetitions of "a"
  34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F
*/

/* #define LITTLE_ENDIAN * This should be #define'd already, if true. */
/* #define SHA1HANDSOFF * Copies data before messing with it. */

#define SHA1HANDSOFF

#include <stdio.h>
#include <string.h>

/* for uint32_t */
#include <stdint.h>

#include "sha1.h"


#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#if BYTE_ORDER == LITTLE_ENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
    |(rol(block->l[i],8)&0x00FF00FF))
#elif BYTE_ORDER == BIG_ENDIAN
#define blk0(i) block->l[i]
#else
#error "Endianness not defined!"
#endif
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
    ^block->l[(i+2)&15]^block->l[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);


/* Hash a single 512-bit block. This is the core of the algorithm. */

void SHA1Transform(
	uint32_t state[5],
	const unsigned char buffer[64]
)
{
	uint32_t a, b, c, d, e;

	typedef union
	{
		unsigned char c[64];
		uint32_t l[16];
	} CHAR64LONG16;

#ifdef SHA1HANDSOFF
	CHAR64LONG16 block[1];      /* use array to appear as a pointer */

	memcpy(block, buffer, 64);
#else
	/* The following had better never be used because it causes the
     * pointer-to-const buffer to be cast into a pointer to non-const.
     * And the result is written through.  I threw a "const" in, hoping
     * this will cause a diagnostic.
     */
    CHAR64LONG16 *block = (const CHAR64LONG16 *) buffer;
#endif
	/* Copy context->state[] to working vars */
	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];
	e = state[4];
	/* 4 rounds of 20 operations each. Loop unrolled. */
	R0(a, b, c, d, e, 0);
	R0(e, a, b, c, d, 1);
	R0(d, e, a, b, c, 2);
	R0(c, d, e, a, b, 3);
	R0(b, c, d, e, a, 4);
	R0(a, b, c, d, e, 5);
	R0(e, a, b, c, d, 6);
	R0(d, e, a, b, c, 7);
	R0(c, d, e, a, b, 8);
	R0(b, c, d, e, a, 9);
	R0(a, b, c, d, e, 10);
	R0(e, a, b, c, d, 11);
	R0(d, e, a, b, c, 12);
	R0(c, d, e, a, b, 13);
	R0(b, c, d, e, a, 14);
	R0(a, b, c, d, e, 15);
	R1(e, a, b, c, d, 16);
	R1(d, e, a, b, c, 17);
	R1(c, d, e, a, b, 18);
	R1(b, c, d, e, a, 19);
	R2(a, b, c, d, e, 20);
	R2(e, a, b, c, d, 21);
	R2(d, e, a, b, c, 22);
	R2(c, d, e, a, b, 23);
	R2(b, c, d, e, a, 24);
	R2(a, b, c, d, e, 25);
	R2(e, a, b, c, d, 26);
	R2(d, e, a, b, c, 27);
	R2(c, d, e, a, b, 28);
	R2(b, c, d, e, a, 29);
	R2(a, b, c, d, e, 30);
	R2(e, a, b, c, d, 31);
	R2(d, e, a, b, c, 32);
	R2(c, d, e, a, b, 33);
	R2(b, c, d, e, a, 34);
	R2(a, b, c, d, e, 35);
	R2(e, a, b, c, d, 36);
	R2(d, e, a, b, c, 37);
	R2(c, d, e, a, b, 38);
	R2(b, c, d, e, a, 39);
	R3(a, b, c, d, e, 40);
	R3(e, a, b, c, d, 41);
	R3(d, e, a, b, c, 42);
	R3(c, d, e, a, b, 43);
	R3(b, c, d, e, a, 44);
	R3(a, b, c, d, e, 45);
	R3(e, a, b, c, d, 46);
	R3(d, e, a, b, c, 47);
	R3(c, d, e, a, b, 48);
	R3(b, c, d, e, a, 49);
	R3(a, b, c, d, e, 50);
	R3(e, a, b, c, d, 51);
	R3(d, e, a, b, c, 52);
	R3(c, d, e, a, b, 53);
	R3(b, c, d, e, a, 54);
	R3(a, b, c, d, e, 55);
	R3(e, a, b, c, d, 56);
	R3(d, e, a, b, c, 57);
	R3(c, d, e, a, b, 58);
	R3(b, c, d, e, a, 59);
	R4(a, b, c, d, e, 60);
	R4(e, a, b, c, d, 61);
	R4(d, e, a, b, c, 62);
	R4(c, d, e, a, b, 63);
	R4(b, c, d, e, a, 64);
	R4(a, b, c, d, e, 65);
	R4(e, a, b, c, d, 66);
	R4(d, e, a, b, c, 67);
	R4(c, d, e, a, b, 68);
	R4(b, c, d, e, a, 69);
	R4(a, b, c, d, e, 70);
	R4(e, a, b, c, d, 71);
	R4(d, e, a, b, c, 72);
	R4(c, d, e, a, b, 73);
	R4(b, c, d, e, a, 74);
	R4(a, b, c, d, e, 75);
	R4(e, a, b, c, d, 76);
	R4(d, e, a, b, c, 77);
	R4(c, d, e, a, b, 78);
	R4(b, c, d, e, a, 79);
	/* Add the working vars back into context.state[] */
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;
	/* Wipe variables */
	a = b = c = d = e = 0;
#ifdef SHA1HANDSOFF
	memset(block, '\0', sizeof(block));
#endif
}


/* SHA1Init - Initialize new context */

void SHA1Init(
	SHA1_CTX * context
)
{
	/* SHA1 initialization constants */
	context->state[0] = 0x67452301;
	context->state[1] = 0xEFCDAB89;
	context->state[2] = 0x98BADCFE;
	context->state[3] = 0x10325476;
	context->state[4] = 0xC3D2E1F0;
	context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */

void SHA1Update(
	SHA1_CTX * context,
	const unsigned char *data,
	uint32_t len
)
{
	uint32_t i;

	uint32_t j;

	j = context->count[0];
	if ((context->count[0] += len << 3) < j)
		context->count[1]++;
	context->count[1] += (len >> 29);
	j = (j >> 3) & 63;
	if ((j + len) > 63)
	{
		memcpy(&context->buffer[j], data, (i = 64 - j));
		SHA1Transform(context->state, context->buffer);
		for (; i + 63 < len; i += 64)
		{
			SHA1Transform(context->state, &data[i]);
		}
		j = 0;
	}
	else
		i = 0;
	memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */

void SHA1Final(
	unsigned char digest[20],
	SHA1_CTX * context
)
{
	unsigned i;

	unsigned char finalcount[8];

	unsigned char c;

#if 0    /* untested "improvement" by DHR */
	/* Convert context->count to a sequence of bytes
     * in finalcount.  Second element first, but
     * big-endian order within element.
     * But we do it all backwards.
     */
    unsigned char *fcp = &finalcount[8];

    for (i = 0; i < 2; i++)
    {
        uint32_t t = context->count[i];

        int j;

        for (j = 0; j < 4; t >>= 8, j++)
            *--fcp = (unsigned char) t}
#else
	for (i = 0; i < 8; i++)
	{
		finalcount[i] = (unsigned char) ((context->count[(i >= 4 ? 0 : 1)] >> ((3 - (i & 3)) * 8)) & 255);      /* Endian independent */
	}
#endif
	c = 0200;
	SHA1Update(context, &c, 1);
	while ((context->count[0] & 504) != 448)
	{
		c = 0000;
		SHA1Update(context, &c, 1);
	}
	SHA1Update(context, finalcount, 8); /* Should cause a SHA1Transform() */
	for (i = 0; i < 20; i++)
	{
		digest[i] = (unsigned char)
			((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
	}
	/* Wipe variables */
	memset(context, '\0', sizeof(*context));
	memset(&finalcount, '\0', sizeof(finalcount));
}

void SHA1(
	char *hash_out,
	const char *str,
	int len)
{
	SHA1_CTX ctx;
	unsigned int ii;

	SHA1Init(&ctx);
	for (ii=0; ii<len; ii+=1)
		SHA1Update(&ctx, (const unsigned char*)str + ii, 1);
	SHA1Final((unsigned char *)hash_out, &ctx);
	hash_out[20] = '\0';
}