utils-std

sha1.c (3700B)

// SPDX-FileCopyrightText: public domain sha1 implementation based on rfc3174 and libtomcrypt
// SPDX-License-Identifier: 0BSD
#include "sha1.h"
#include <string.h>
static uint32_t
rol(uint32_t n, int k)
{
	return (n << k) | (n >> (32 - k));
}
#define F0(b, c, d) (d ^ (b & (c ^ d)))
#define F1(b, c, d) (b ^ c ^ d)
#define F2(b, c, d) ((b & c) | (d & (b | c)))
#define F3(b, c, d) (b ^ c ^ d)
#define G0(a, b, c, d, e, i)                                                                       \
	e += rol(a, 5) + F0(b, c, d) + W[i] + 0x5A827999;                                                \
	b = rol(b, 30)
#define G1(a, b, c, d, e, i)                                                                       \
	e += rol(a, 5) + F1(b, c, d) + W[i] + 0x6ED9EBA1;                                                \
	b = rol(b, 30)
#define G2(a, b, c, d, e, i)                                                                       \
	e += rol(a, 5) + F2(b, c, d) + W[i] + 0x8F1BBCDC;                                                \
	b = rol(b, 30)
#define G3(a, b, c, d, e, i)                                                                       \
	e += rol(a, 5) + F3(b, c, d) + W[i] + 0xCA62C1D6;                                                \
	b = rol(b, 30)
static void
processblock(struct sha1 *s, const uint8_t *buf)
{
	uint32_t W[80], a, b, c, d, e;
	int i;
	for(i = 0; i < 16; i++)
	{
		W[i] = (uint32_t)buf[4 * i] << 24;
		W[i] |= (uint32_t)buf[4 * i + 1] << 16;
		W[i] |= (uint32_t)buf[4 * i + 2] << 8;
		W[i] |= buf[4 * i + 3];
	}
	for(; i < 80; i++)
		W[i] = rol(W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16], 1);
	a = s->h[0];
	b = s->h[1];
	c = s->h[2];
	d = s->h[3];
	e = s->h[4];
	for(i = 0; i < 20;)
	{
		G0(a, b, c, d, e, i++);
		G0(e, a, b, c, d, i++);
		G0(d, e, a, b, c, i++);
		G0(c, d, e, a, b, i++);
		G0(b, c, d, e, a, i++);
	}
	while(i < 40)
	{
		G1(a, b, c, d, e, i++);
		G1(e, a, b, c, d, i++);
		G1(d, e, a, b, c, i++);
		G1(c, d, e, a, b, i++);
		G1(b, c, d, e, a, i++);
	}
	while(i < 60)
	{
		G2(a, b, c, d, e, i++);
		G2(e, a, b, c, d, i++);
		G2(d, e, a, b, c, i++);
		G2(c, d, e, a, b, i++);
		G2(b, c, d, e, a, i++);
	}
	while(i < 80)
	{
		G3(a, b, c, d, e, i++);
		G3(e, a, b, c, d, i++);
		G3(d, e, a, b, c, i++);
		G3(c, d, e, a, b, i++);
		G3(b, c, d, e, a, i++);
	}
	s->h[0] += a;
	s->h[1] += b;
	s->h[2] += c;
	s->h[3] += d;
	s->h[4] += e;
}
static void
pad(struct sha1 *s)
{
	unsigned r = s->len % 64;
	s->buf[r++] = 0x80;
	if(r > 56)
	{
		memset(s->buf + r, 0, 64 - r);
		r = 0;
		processblock(s, s->buf);
	}
	memset(s->buf + r, 0, 56 - r);
	s->len *= 8;
	s->buf[56] = s->len >> 56;
	s->buf[57] = s->len >> 48;
	s->buf[58] = s->len >> 40;
	s->buf[59] = s->len >> 32;
	s->buf[60] = s->len >> 24;
	s->buf[61] = s->len >> 16;
	s->buf[62] = s->len >> 8;
	s->buf[63] = s->len;
	processblock(s, s->buf);
}
void
sha1_init(void *ctx)
{
	struct sha1 *s = ctx;
	s->len = 0;
	s->h[0] = 0x67452301;
	s->h[1] = 0xEFCDAB89;
	s->h[2] = 0x98BADCFE;
	s->h[3] = 0x10325476;
	s->h[4] = 0xC3D2E1F0;
}
void
sha1_sum(void *ctx, uint8_t md[SHA1_DIGEST_LENGTH])
{
	struct sha1 *s = ctx;
	int i;
	pad(s);
	for(i = 0; i < 5; i++)
	{
		md[4 * i] = s->h[i] >> 24;
		md[4 * i + 1] = s->h[i] >> 16;
		md[4 * i + 2] = s->h[i] >> 8;
		md[4 * i + 3] = s->h[i];
	}
}
void
sha1_update(void *ctx, const void *m, unsigned long len)
{
	struct sha1 *s = ctx;
	const uint8_t *p = m;
	unsigned r = s->len % 64;
	s->len += len;
	if(r)
	{
		if(len < 64 - r)
		{
			memcpy(s->buf + r, p, len);
			return;
		}
		memcpy(s->buf + r, p, 64 - r);
		len -= 64 - r;
		p += 64 - r;
		processblock(s, s->buf);
	}
	for(; len >= 64; len -= 64, p += 64)
		processblock(s, p);
	memcpy(s->buf, p, len);
}