/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com */#include "tomcrypt.h"/**  @file hmac_done.c  HMAC support, terminate stream, Tom St Denis/Dobes Vandermeer*/#ifdef LTC_HMAC#define HMAC_BLOCKSIZE hash_descriptor[hash].blocksize/**   Terminate an HMAC session   @param hmac    The HMAC state   @param out     [out] The destination of the HMAC authentication tag   @param outlen  [in/out]  The max size and resulting size of the HMAC authentication tag   @return CRYPT_OK if successful*/int hmac_done(hmac_state *hmac, unsigned char *out, unsigned long *outlen){    unsigned char *buf, *isha;    unsigned long hashsize, i;    int hash, err;    LTC_ARGCHK(hmac  != NULL);    LTC_ARGCHK(out   != NULL);    /* test hash */    hash = hmac->hash;    if((err = hash_is_valid(hash)) != CRYPT_OK) {        return err;    }    /* get the hash message digest size */    hashsize = hash_descriptor[hash].hashsize;    /* allocate buffers */    buf  = XMALLOC(HMAC_BLOCKSIZE);    isha = XMALLOC(hashsize);    if (buf == NULL || isha == NULL) {        if (buf != NULL) {          XFREE(buf);       }        if (isha != NULL) {          XFREE(isha);       }         return CRYPT_MEM;    }    /* Get the hash of the first HMAC vector plus the data */    if ((err = hash_descriptor[hash].done(&hmac->md, isha)) != CRYPT_OK) {       goto LBL_ERR;    }    /* Create the second HMAC vector vector for step (3) */    for(i=0; i < HMAC_BLOCKSIZE; i++) {        buf[i] = hmac->key[i] ^ 0x5C;    }    /* Now calculate the "outer" hash for step (5), (6), and (7) */    if ((err = hash_descriptor[hash].init(&hmac->md)) != CRYPT_OK) {       goto LBL_ERR;    }    if ((err = hash_descriptor[hash].process(&hmac->md, buf, HMAC_BLOCKSIZE)) != CRYPT_OK) {       goto LBL_ERR;    }    if ((err = hash_descriptor[hash].process(&hmac->md, isha, hashsize)) != CRYPT_OK) {       goto LBL_ERR;    }    if ((err = hash_descriptor[hash].done(&hmac->md, buf)) != CRYPT_OK) {       goto LBL_ERR;    }    /* copy to output  */    for (i = 0; i < hashsize && i < *outlen; i++) {        out[i] = buf[i];    }    *outlen = i;    err = CRYPT_OK;LBL_ERR:    XFREE(hmac->key);#ifdef LTC_CLEAN_STACK    zeromem(isha, hashsize);    zeromem(buf,  hashsize);    zeromem(hmac, sizeof(*hmac));#endif    XFREE(isha);    XFREE(buf);    return err;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/mac/hmac/hmac_done.c,v $ *//* $Revision: 1.5 $ *//* $Date: 2006/11/03 00:39:49 $ */