diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/encauth/gcm/gcm_done.c')
-rw-r--r-- | core/lib/libtomcrypt/src/encauth/gcm/gcm_done.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/encauth/gcm/gcm_done.c b/core/lib/libtomcrypt/src/encauth/gcm/gcm_done.c new file mode 100644 index 0000000..28d0909 --- /dev/null +++ b/core/lib/libtomcrypt/src/encauth/gcm/gcm_done.c @@ -0,0 +1,110 @@ +/* + * Copyright (c) 2001-2007, Tom St Denis + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* 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://libtom.org + */ + +/** + @file gcm_done.c + GCM implementation, Terminate the stream, by Tom St Denis +*/ +#include "tomcrypt.h" + +#ifdef LTC_GCM_MODE + +/** + Terminate a GCM stream + @param gcm The GCM state + @param tag [out] The destination for the MAC tag + @param taglen [in/out] The length of the MAC tag + @return CRYPT_OK on success + */ +int gcm_done(gcm_state *gcm, + unsigned char *tag, unsigned long *taglen) +{ + unsigned long x; + int err; + + LTC_ARGCHK(gcm != NULL); + LTC_ARGCHK(tag != NULL); + LTC_ARGCHK(taglen != NULL); + + if (gcm->buflen > 16 || gcm->buflen < 0) { + return CRYPT_INVALID_ARG; + } + + if ((err = cipher_is_valid(gcm->cipher)) != CRYPT_OK) { + return err; + } + + + if (gcm->mode != LTC_GCM_MODE_TEXT) { + return CRYPT_INVALID_ARG; + } + + /* handle remaining ciphertext */ + if (gcm->buflen) { + gcm->pttotlen += gcm->buflen * CONST64(8); + gcm_mult_h(gcm, gcm->X); + } + + /* length */ + STORE64H(gcm->totlen, gcm->buf); + STORE64H(gcm->pttotlen, gcm->buf+8); + for (x = 0; x < 16; x++) { + gcm->X[x] ^= gcm->buf[x]; + } + gcm_mult_h(gcm, gcm->X); + + /* encrypt original counter */ + if ((err = cipher_descriptor[gcm->cipher]->ecb_encrypt(gcm->Y_0, gcm->buf, &gcm->K)) != CRYPT_OK) { + return err; + } + for (x = 0; x < 16 && x < *taglen; x++) { + tag[x] = gcm->buf[x] ^ gcm->X[x]; + } + *taglen = x; + + cipher_descriptor[gcm->cipher]->done(&gcm->K); + + return CRYPT_OK; +} + +#endif + + +/* $Source: /cvs/libtom/libtomcrypt/src/encauth/gcm/gcm_done.c,v $ */ +/* $Revision: 1.11 $ */ +/* $Date: 2007/05/12 14:32:35 $ */ |