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/*
* Copyright (C) 2016 Oliver Hahm <oliver.hahm@inria.fr>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/* This code is public-domain - it is based on libcrypt
* placed in the public domain by Wei Dai and other contributors.
*/
/**
* @defgroup sys_hashes_sha1 SHA-1
* @ingroup sys_hashes
* @brief Implementation of the SHA-1 hashing function
* @{
*
* @file
* @brief SHA-1 interface definition
*
* @author Wei Dai and others
* @author Oliver Hahm <oliver.hahm@inria.fr>
*/
#include <stdint.h>
#include <string.h>
#include "hashes/sha1.h"
#define SHA1_K0 0x5a827999
#define SHA1_K20 0x6ed9eba1
#define SHA1_K40 0x8f1bbcdc
#define SHA1_K60 0xca62c1d6
void sha1_init(sha1_context *ctx)
{
ctx->state[0] = 0x67452301;
ctx->state[1] = 0xefcdab89;
ctx->state[2] = 0x98badcfe;
ctx->state[3] = 0x10325476;
ctx->state[4] = 0xc3d2e1f0;
ctx->byte_count = 0;
ctx->buffer_offset = 0;
}
static uint32_t sha1_rol32(uint32_t number, uint8_t bits)
{
return ((number << bits) | (number >> (32 - bits)));
}
static void sha1_hash_block(sha1_context *s)
{
uint8_t i;
uint32_t a, b, c, d, e, t;
a = s->state[0];
b = s->state[1];
c = s->state[2];
d = s->state[3];
e = s->state[4];
for (i = 0; i < 80; i++) {
if (i >= 16) {
t = s->buffer[(i + 13) & 15] ^ s->buffer[(i + 8) & 15] ^
s->buffer[(i + 2) & 15] ^ s->buffer[i & 15];
s->buffer[i & 15] = sha1_rol32(t, 1);
}
if (i < 20) {
t = (d ^ (b & (c ^ d))) + SHA1_K0;
}
else if (i < 40) {
t = (b ^ c ^ d) + SHA1_K20;
}
else if (i < 60) {
t = ((b & c) | (d & (b | c))) + SHA1_K40;
}
else {
t = (b ^ c ^ d) + SHA1_K60;
}
t += sha1_rol32(a, 5) + e + s->buffer[i & 15];
e = d;
d = c;
c = sha1_rol32(b, 30);
b = a;
a = t;
}
s->state[0] += a;
s->state[1] += b;
s->state[2] += c;
s->state[3] += d;
s->state[4] += e;
}
static void sha1_add_uncounted(sha1_context *s, uint8_t data)
{
uint8_t *const b = (uint8_t *) s->buffer;
#ifdef __BIG_ENDIAN__
b[s->buffer_offset] = data;
#else
b[s->buffer_offset ^ 3] = data;
#endif
s->buffer_offset++;
if (s->buffer_offset == SHA1_BLOCK_LENGTH) {
sha1_hash_block(s);
s->buffer_offset = 0;
}
}
static void sha1_update_byte(sha1_context *ctx, uint8_t data)
{
++ctx->byte_count;
sha1_add_uncounted(ctx, data);
}
void sha1_update(sha1_context *ctx, const void *data, size_t len)
{
const uint8_t *d = data;
while (len--) {
sha1_update_byte(ctx, *(d++));
}
}
static void sha1_pad(sha1_context *s)
{
/* Implement SHA-1 padding (fips180-2 §5.1.1) */
/* Pad with 0x80 followed by 0x00 until the end of the block */
sha1_add_uncounted(s, 0x80);
while (s->buffer_offset != 56) {
sha1_add_uncounted(s, 0x00);
}
/* Append length in the last 8 bytes */
sha1_add_uncounted(s, 0); /* We're only using 32 bit lengths */
sha1_add_uncounted(s, 0); /* But SHA-1 supports 64 bit lengths */
sha1_add_uncounted(s, 0); /* So zero pad the top bits */
sha1_add_uncounted(s, s->byte_count >> 29); /* Shifting to multiply by 8 */
sha1_add_uncounted(s, s->byte_count >> 21); /* as SHA-1 supports bitstreams as well as */
sha1_add_uncounted(s, s->byte_count >> 13); /* byte. */
sha1_add_uncounted(s, s->byte_count >> 5);
sha1_add_uncounted(s, s->byte_count << 3);
}
void sha1_final(sha1_context *ctx, void *digest)
{
/* Pad to complete the last block */
sha1_pad(ctx);
/* Swap byte order back */
for (int i = 0; i < 5; i++) {
ctx->state[i] =
(((ctx->state[i]) << 24) & 0xff000000)
| (((ctx->state[i]) << 8) & 0x00ff0000)
| (((ctx->state[i]) >> 8) & 0x0000ff00)
| (((ctx->state[i]) >> 24) & 0x000000ff);
}
/* Copy the content of the hash (20 characters) */
memcpy(digest, ctx->state, 20);
}
void sha1(void *digest, const void *data, size_t len)
{
sha1_context ctx;
sha1_init(&ctx);
sha1_update(&ctx, (unsigned char *) data, len);
sha1_final(&ctx, digest);
}
#define HMAC_IPAD 0x36
#define HMAC_OPAD 0x5c
void sha1_init_hmac(sha1_context *ctx, const void *key, size_t key_length)
{
uint8_t i;
const uint8_t *k = key;
memset(ctx->key_buffer, 0, SHA1_BLOCK_LENGTH);
if (key_length > SHA1_BLOCK_LENGTH) {
/* Hash long keys */
sha1_init(ctx);
while (key_length--) {
sha1_update_byte(ctx, *k++);
}
sha1_final(ctx, ctx->key_buffer);
}
else {
/* Block length keys are used as is */
memcpy(ctx->key_buffer, key, key_length);
}
/* Start inner hash */
sha1_init(ctx);
for (i = 0; i < SHA1_BLOCK_LENGTH; i++) {
sha1_update_byte(ctx, ctx->key_buffer[i] ^ HMAC_IPAD);
}
}
void sha1_final_hmac(sha1_context *ctx, void *digest)
{
uint8_t i;
/* Complete inner hash */
sha1_final(ctx, ctx->inner_hash);
/* Calculate outer hash */
sha1_init(ctx);
for (i = 0; i < SHA1_BLOCK_LENGTH; i++) {
sha1_update_byte(ctx, ctx->key_buffer[i] ^ HMAC_OPAD);
}
for (i = 0; i < SHA1_DIGEST_LENGTH; i++) {
sha1_update_byte(ctx, ctx->inner_hash[i]);
}
sha1_final(ctx, digest);
}