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/* 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 f9_done.c
f9 Support, terminate the state
*/
#ifdef LTC_F9_MODE
/** Terminate the f9-MAC state
@param f9 f9 state to terminate
@param out [out] Destination for the MAC tag
@param outlen [in/out] Destination size and final tag size
Return CRYPT_OK on success
*/
int f9_done(f9_state *f9, unsigned char *out, unsigned long *outlen)
{
int err, x;
LTC_ARGCHK(f9 != NULL);
LTC_ARGCHK(out != NULL);
/* check structure */
if ((err = cipher_is_valid(f9->cipher)) != CRYPT_OK) {
return err;
}
if ((f9->blocksize > cipher_descriptor[f9->cipher].block_length) || (f9->blocksize < 0) ||
(f9->buflen > f9->blocksize) || (f9->buflen < 0)) {
return CRYPT_INVALID_ARG;
}
if (f9->buflen != 0) {
/* encrypt */
cipher_descriptor[f9->cipher].ecb_encrypt(f9->IV, f9->IV, &f9->key);
f9->buflen = 0;
for (x = 0; x < f9->blocksize; x++) {
f9->ACC[x] ^= f9->IV[x];
}
}
/* schedule modified key */
if ((err = cipher_descriptor[f9->cipher].setup(f9->akey, f9->keylen, 0, &f9->key)) != CRYPT_OK) {
return err;
}
/* encrypt the ACC */
cipher_descriptor[f9->cipher].ecb_encrypt(f9->ACC, f9->ACC, &f9->key);
cipher_descriptor[f9->cipher].done(&f9->key);
/* extract tag */
for (x = 0; x < f9->blocksize && (unsigned long)x < *outlen; x++) {
out[x] = f9->ACC[x];
}
*outlen = x;
#ifdef LTC_CLEAN_STACK
zeromem(f9, sizeof(*f9));
#endif
return CRYPT_OK;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/mac/f9/f9_done.c,v $ */
/* $Revision: 1.5 $ */
/* $Date: 2006/11/09 01:53:32 $ */
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