| /* 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@iahu.ca, http://libtomcrypt.org |
| */ |
| |
| /* OCB Implementation by Tom St Denis */ |
| #include "mycrypt.h" |
| |
| #ifdef OCB_MODE |
| |
| int ocb_done_decrypt(ocb_state *ocb, |
| const unsigned char *ct, unsigned long ctlen, |
| unsigned char *pt, |
| const unsigned char *tag, unsigned long taglen, int *res) |
| { |
| int err; |
| unsigned char *tagbuf; |
| unsigned long tagbuflen; |
| |
| _ARGCHK(ocb != NULL); |
| _ARGCHK(pt != NULL); |
| _ARGCHK(ct != NULL); |
| _ARGCHK(tag != NULL); |
| _ARGCHK(res != NULL); |
| |
| /* default to failed */ |
| *res = 0; |
| |
| /* allocate memory */ |
| tagbuf = XMALLOC(MAXBLOCKSIZE); |
| if (tagbuf == NULL) { |
| return CRYPT_MEM; |
| } |
| |
| tagbuflen = MAXBLOCKSIZE; |
| if ((err = __ocb_done(ocb, ct, ctlen, pt, tagbuf, &tagbuflen, 1)) != CRYPT_OK) { |
| goto __ERR; |
| } |
| |
| if (taglen <= tagbuflen && memcmp(tagbuf, tag, taglen) == 0) { |
| *res = 1; |
| } |
| |
| err = CRYPT_OK; |
| __ERR: |
| #ifdef CLEAN_STACK |
| zeromem(tagbuf, MAXBLOCKSIZE); |
| #endif |
| |
| XFREE(tagbuf); |
| |
| return err; |
| } |
| |
| #endif |
| |