139 lines
3.4 KiB
C
139 lines
3.4 KiB
C
/* hmac-sha1.c */
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/*
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This file is part of the Crypto-avr-lib/microcrypt-lib.
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Copyright (C) 2008 Daniel Otte (daniel.otte@rub.de)
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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*
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* implementation of HMAC as described in RFC2104
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* Author: Daniel Otte
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* email: daniel.otte@rub.de
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* License: GPLv3 or later
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**/
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/*
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* hmac = hash ( k^opad , hash( k^ipad , msg))
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*/
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#include <stdint.h>
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#include <string.h>
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#include "config.h"
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#include "sha1.h"
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#define IPAD 0x36
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#define OPAD 0x5C
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typedef sha1_ctx_t hmac_sha1_ctx_t;
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#ifndef HMAC_SHORTONLY
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void hmac_sha1_init(hmac_sha1_ctx_t *s, void* key, uint16_t keylength_b){
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uint8_t buffer[SHA1_BLOCK_BYTES];
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uint8_t i;
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memset(buffer, 0, SHA1_BLOCK_BYTES);
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if (keylength_b > SHA1_BLOCK_BITS){
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sha1((void*)buffer, key, keylength_b);
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} else {
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memcpy(buffer, key, (keylength_b+7)/8);
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}
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for (i=0; i<SHA1_BLOCK_BYTES; ++i){
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buffer[i] ^= IPAD;
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}
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sha1_init(s);
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sha1_nextBlock(s, buffer);
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#if defined SECURE_WIPE_BUFFER
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memset(buffer, 0, SHA256_BLOCK_BITS/8);
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#endif
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}
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void hmac_sha1_final(hmac_sha1_ctx_t *s, void* key, uint16_t keylength_b){
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uint8_t buffer[SHA1_BLOCK_BYTES];
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uint8_t i;
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sha1_ctx_t a;
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memset(buffer, 0, SHA1_BLOCK_BYTES);
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if (keylength_b > SHA1_BLOCK_BITS){
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sha1((void*)buffer, key, keylength_b);
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} else {
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memcpy(buffer, key, (keylength_b+7)/8);
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}
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for (i=0; i<SHA1_BLOCK_BYTES; ++i){
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buffer[i] ^= OPAD;
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}
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sha1_init(&a);
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sha1_nextBlock(&a, buffer); /* hash key ^ opad */
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sha1_ctx2hash((void*)buffer, s); /* copy hash(key ^ ipad, msg) to buffer */
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sha1_lastBlock(&a, buffer, SHA1_HASH_BITS);
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memcpy(s, &a, sizeof(sha1_ctx_t));
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#if defined SECURE_WIPE_BUFFER
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memset(buffer, 0, SHA1_BLOCK_BYTES);
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memset(a.h, 0, 20);
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#endif
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}
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#endif
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/*
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void hmac_sha1_nextBlock()
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void hmac_sha1_lastBlock()
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*/
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/*
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* keylength in bits!
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* message length in bits!
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*/
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void hmac_sha1(void* dest, void* key, uint16_t keylength_b, void* msg, uint64_t msglength_b){ /* a one-shot*/
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sha1_ctx_t s;
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uint8_t i;
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uint8_t buffer[SHA1_BLOCK_BYTES];
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memset(buffer, 0, SHA1_BLOCK_BYTES);
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/* if key is larger than a block we have to hash it*/
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if (keylength_b > SHA1_BLOCK_BITS){
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sha1((void*)buffer, key, keylength_b);
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} else {
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memcpy(buffer, key, (keylength_b+7)/8);
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}
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for (i=0; i<SHA1_BLOCK_BYTES; ++i){
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buffer[i] ^= IPAD;
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}
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sha1_init(&s);
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sha1_nextBlock(&s, buffer);
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while (msglength_b >= SHA1_BLOCK_BITS){
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sha1_nextBlock(&s, msg);
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msg = (uint8_t*)msg + SHA1_BLOCK_BYTES;
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msglength_b -= SHA1_BLOCK_BITS;
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}
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sha1_lastBlock(&s, msg, msglength_b);
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/* since buffer still contains key xor ipad we can do ... */
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for (i=0; i<SHA1_BLOCK_BYTES; ++i){
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buffer[i] ^= IPAD ^ OPAD;
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}
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sha1_ctx2hash(dest, &s); /* save inner hash temporary to dest */
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sha1_init(&s);
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sha1_nextBlock(&s, buffer);
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sha1_lastBlock(&s, dest, SHA1_HASH_BITS);
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sha1_ctx2hash(dest, &s);
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}
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