/* 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_MODEint 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[MAXBLOCKSIZE];   unsigned long tagbuflen;   _ARGCHK(ocb != NULL);   _ARGCHK(pt  != NULL);   _ARGCHK(ct  != NULL);   _ARGCHK(tag != NULL);   _ARGCHK(res != NULL);   *res = 0;   tagbuflen = sizeof(tagbuf);   if ((err = __ocb_done(ocb, ct, ctlen, pt, tagbuf, &tagbuflen, 1)) != CRYPT_OK) {      return err;   }   if (taglen <= tagbuflen && memcmp(tagbuf, tag, taglen) == 0) {      *res = 1;   }#ifdef CLEAN_STACK   zeromem(tagbuf, sizeof(tagbuf));#endif   return CRYPT_OK;}#endif