| // SPDX-License-Identifier: BSD-2-Clause |
| /* 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. |
| */ |
| #include "tomcrypt_private.h" |
| |
| #ifdef LTC_CCM_MODE |
| |
| /** |
| Terminate a CCM stream |
| @param ccm The CCM 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 ccm_done(ccm_state *ccm, |
| unsigned char *tag, unsigned long *taglen) |
| { |
| unsigned long x, y; |
| int err; |
| |
| LTC_ARGCHK(ccm != NULL); |
| |
| /* Check all data have been processed */ |
| if (ccm->ptlen != ccm->current_ptlen) { |
| return CRYPT_ERROR; |
| } |
| |
| LTC_ARGCHK(tag != NULL); |
| LTC_ARGCHK(taglen != NULL); |
| |
| if (ccm->x != 0) { |
| if ((err = cipher_descriptor[ccm->cipher]->ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) { |
| return err; |
| } |
| } |
| |
| /* setup CTR for the TAG (zero the count) */ |
| for (y = 15; y > 15 - ccm->L; y--) { |
| ccm->ctr[y] = 0x00; |
| } |
| if ((err = cipher_descriptor[ccm->cipher]->ecb_encrypt(ccm->ctr, ccm->CTRPAD, &ccm->K)) != CRYPT_OK) { |
| return err; |
| } |
| |
| cipher_descriptor[ccm->cipher]->done(&ccm->K); |
| |
| /* store the TAG */ |
| for (x = 0; x < 16 && x < *taglen; x++) { |
| tag[x] = ccm->PAD[x] ^ ccm->CTRPAD[x]; |
| } |
| *taglen = x; |
| |
| return CRYPT_OK; |
| } |
| |
| #endif |
| |
| /* ref: $Format:%D$ */ |
| /* git commit: $Format:%H$ */ |
| /* commit time: $Format:%ai$ */ |