diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/encauth/gcm/gcm_add_aad.c')
| -rw-r--r-- | core/lib/libtomcrypt/src/encauth/gcm/gcm_add_aad.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/encauth/gcm/gcm_add_aad.c b/core/lib/libtomcrypt/src/encauth/gcm/gcm_add_aad.c new file mode 100644 index 0000000..b8e6285 --- /dev/null +++ b/core/lib/libtomcrypt/src/encauth/gcm/gcm_add_aad.c @@ -0,0 +1,151 @@ +/* + * 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_add_aad.c + GCM implementation, Add AAD data to the stream, by Tom St Denis +*/ +#include "tomcrypt.h" + +#ifdef LTC_GCM_MODE + +/** + Add AAD to the GCM state + @param gcm The GCM state + @param adata The additional authentication data to add to the GCM state + @param adatalen The length of the AAD data. + @return CRYPT_OK on success + */ +int gcm_add_aad(gcm_state *gcm, + const unsigned char *adata, unsigned long adatalen) +{ + unsigned long x; + int err; +#ifdef LTC_FAST + unsigned long y; +#endif + + LTC_ARGCHK(gcm != NULL); + if (adatalen > 0) { + LTC_ARGCHK(adata != NULL); + } + + if (gcm->buflen > 16 || gcm->buflen < 0) { + return CRYPT_INVALID_ARG; + } + + if ((err = cipher_is_valid(gcm->cipher)) != CRYPT_OK) { + return err; + } + + /* in IV mode? */ + if (gcm->mode == LTC_GCM_MODE_IV) { + /* let's process the IV */ + if (gcm->ivmode || gcm->buflen != 12) { + for (x = 0; x < (unsigned long)gcm->buflen; x++) { + gcm->X[x] ^= gcm->buf[x]; + } + if (gcm->buflen) { + gcm->totlen += gcm->buflen * CONST64(8); + gcm_mult_h(gcm, gcm->X); + } + + /* mix in the length */ + zeromem(gcm->buf, 8); + STORE64H(gcm->totlen, gcm->buf+8); + for (x = 0; x < 16; x++) { + gcm->X[x] ^= gcm->buf[x]; + } + gcm_mult_h(gcm, gcm->X); + + /* copy counter out */ + XMEMCPY(gcm->Y, gcm->X, 16); + zeromem(gcm->X, 16); + } else { + XMEMCPY(gcm->Y, gcm->buf, 12); + gcm->Y[12] = 0; + gcm->Y[13] = 0; + gcm->Y[14] = 0; + gcm->Y[15] = 1; + } + XMEMCPY(gcm->Y_0, gcm->Y, 16); + zeromem(gcm->buf, 16); + gcm->buflen = 0; + gcm->totlen = 0; + gcm->mode = LTC_GCM_MODE_AAD; + } + + if (gcm->mode != LTC_GCM_MODE_AAD || gcm->buflen >= 16) { + return CRYPT_INVALID_ARG; + } + + x = 0; +#ifdef LTC_FAST + if (gcm->buflen == 0) { + for (x = 0; x < (adatalen & ~15); x += 16) { + for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) { + *((LTC_FAST_TYPE*)(&gcm->X[y])) ^= *((LTC_FAST_TYPE*)(&adata[x + y])); + } + gcm_mult_h(gcm, gcm->X); + gcm->totlen += 128; + } + adata += x; + } +#endif + + + /* start adding AAD data to the state */ + for (; x < adatalen; x++) { + gcm->X[gcm->buflen++] ^= *adata++; + + if (gcm->buflen == 16) { + /* GF mult it */ + gcm_mult_h(gcm, gcm->X); + gcm->buflen = 0; + gcm->totlen += 128; + } + } + + return CRYPT_OK; +} +#endif + + +/* $Source: /cvs/libtom/libtomcrypt/src/encauth/gcm/gcm_add_aad.c,v $ */ +/* $Revision: 1.18 $ */ +/* $Date: 2007/05/12 14:32:35 $ */ |