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103 lines
2.6 KiB
103 lines
2.6 KiB
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@gmail.com, http://libtom.org
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*/
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#include "tomcrypt.h"
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/**
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@file hmac_done.c
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LTC_HMAC support, terminate stream, Tom St Denis/Dobes Vandermeer
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*/
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#ifdef LTC_HMAC
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#define LTC_HMAC_BLOCKSIZE hash->blocksize
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/**
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Terminate an LTC_HMAC session
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@param hmac The LTC_HMAC state
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@param out [out] The destination of the LTC_HMAC authentication tag
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@param outlen [in/out] The max size and resulting size of the LTC_HMAC authentication tag
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@return CRYPT_OK if successful
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*/
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int hmac_done(hmac_state *hmac,const struct ltc_hash_descriptor *hash,unsigned char *out,unsigned long *outlen)
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{
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unsigned char *buf, *isha;
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unsigned long hashsize, i;
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int err;
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LTC_ARGCHK(hmac != NULL);
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LTC_ARGCHK(out != NULL);
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/* get the hash message digest size */
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hashsize = hash->hashsize;
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/* allocate buffers */
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buf = XMALLOC(LTC_HMAC_BLOCKSIZE);
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isha = XMALLOC(hashsize);
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if (buf == NULL || isha == NULL) {
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if (buf != NULL) {
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XFREE(buf);
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}
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if (isha != NULL) {
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XFREE(isha);
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}
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return CRYPT_MEM;
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}
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/* Get the hash of the first LTC_HMAC vector plus the data */
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if ((err = hash->done(&hmac->md, isha)) != CRYPT_OK) {
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goto LBL_ERR;
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}
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/* Create the second LTC_HMAC vector vector for step (3) */
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for(i=0; i < LTC_HMAC_BLOCKSIZE; i++) {
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buf[i] = hmac->key[i] ^ 0x5C;
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}
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/* Now calculate the "outer" hash for step (5), (6), and (7) */
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if ((err = hash->init(&hmac->md)) != CRYPT_OK) {
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goto LBL_ERR;
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}
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if ((err = hash->process(&hmac->md, buf, LTC_HMAC_BLOCKSIZE)) != CRYPT_OK) {
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goto LBL_ERR;
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}
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if ((err = hash->process(&hmac->md, isha, hashsize)) != CRYPT_OK) {
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goto LBL_ERR;
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}
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if ((err = hash->done(&hmac->md, buf)) != CRYPT_OK) {
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goto LBL_ERR;
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}
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/* copy to output */
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for (i = 0; i < hashsize && i < *outlen; i++) {
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out[i] = buf[i];
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}
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*outlen = i;
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err = CRYPT_OK;
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LBL_ERR:
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XFREE(hmac->key);
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#ifdef LTC_CLEAN_STACK
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zeromem(isha, hashsize);
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zeromem(buf, hashsize);
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zeromem(hmac, sizeof(*hmac));
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#endif
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XFREE(isha);
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XFREE(buf);
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return err;
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}
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#endif
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/* $Source: /cvs/libtom/libtomcrypt/src/mac/hmac/hmac_done.c,v $ */
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/* $Revision: 1.7 $ */
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/* $Date: 2007/05/12 14:37:41 $ */
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