diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/encauth/ccm/ccm_add_nonce.c')
-rw-r--r-- | core/lib/libtomcrypt/src/encauth/ccm/ccm_add_nonce.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/encauth/ccm/ccm_add_nonce.c b/core/lib/libtomcrypt/src/encauth/ccm/ccm_add_nonce.c new file mode 100644 index 0000000..9097670 --- /dev/null +++ b/core/lib/libtomcrypt/src/encauth/ccm/ccm_add_nonce.c @@ -0,0 +1,139 @@ +/* + * Copyright (c) 2001-2007, Tom St Denis + * Copyright (c) 2014, STMicroelectronics International N.V. + * 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 + */ +#include "tomcrypt.h" + +#ifdef LTC_CCM_MODE + +/** + Add nonce data to the CCM state + @param ccm The CCM state + @param nonce The nonce data to add + @param noncelen The length of the nonce + @return CRYPT_OK on success + */ +int ccm_add_nonce(ccm_state *ccm, + const unsigned char *nonce, unsigned long noncelen) +{ + unsigned long x, y, len; + int err; + + LTC_ARGCHK(ccm != NULL); + LTC_ARGCHK(nonce != NULL); + + /* increase L to match the nonce len */ + ccm->noncelen = (noncelen > 13) ? 13 : noncelen; + if ((15 - ccm->noncelen) > ccm->L) { + ccm->L = 15 - ccm->noncelen; + } + + /* decrease noncelen to match L */ + if ((ccm->noncelen + ccm->L) > 15) { + ccm->noncelen = 15 - ccm->L; + } + + /* form B_0 == flags | Nonce N | l(m) */ + x = 0; + ccm->PAD[x++] = (unsigned char)(((ccm->aadlen > 0) ? (1<<6) : 0) | + (((ccm->taglen - 2)>>1)<<3) | + (ccm->L-1)); + + /* nonce */ + for (y = 0; y < (16 - (ccm->L + 1)); y++) { + ccm->PAD[x++] = nonce[y]; + } + + /* store len */ + len = ccm->ptlen; + + /* shift len so the upper bytes of len are the contents of the length */ + for (y = ccm->L; y < 4; y++) { + len <<= 8; + } + + /* store l(m) (only store 32-bits) */ + for (y = 0; ccm->L > 4 && (ccm->L-y)>4; y++) { + ccm->PAD[x++] = 0; + } + for (; y < ccm->L; y++) { + ccm->PAD[x++] = (unsigned char)((len >> 24) & 255); + len <<= 8; + } + + /* encrypt PAD */ + if ((err = cipher_descriptor[ccm->cipher]->ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) { + return err; + } + + /* handle header */ + ccm->x = 0; + if (ccm->aadlen > 0) { + /* store length */ + if (ccm->aadlen < ((1UL<<16) - (1UL<<8))) { + ccm->PAD[ccm->x++] ^= (ccm->aadlen>>8) & 255; + ccm->PAD[ccm->x++] ^= ccm->aadlen & 255; + } else { + ccm->PAD[ccm->x++] ^= 0xFF; + ccm->PAD[ccm->x++] ^= 0xFE; + ccm->PAD[ccm->x++] ^= (ccm->aadlen>>24) & 255; + ccm->PAD[ccm->x++] ^= (ccm->aadlen>>16) & 255; + ccm->PAD[ccm->x++] ^= (ccm->aadlen>>8) & 255; + ccm->PAD[ccm->x++] ^= ccm->aadlen & 255; + } + } + + /* setup the ctr counter */ + x = 0; + + /* flags */ + ccm->ctr[x++] = (unsigned char)ccm->L-1; + + /* nonce */ + for (y = 0; y < (16 - (ccm->L+1)); ++y) { + ccm->ctr[x++] = nonce[y]; + } + /* offset */ + while (x < 16) { + ccm->ctr[x++] = 0; + } + + ccm->CTRlen = 16; + return CRYPT_OK; +} + +#endif |