/* 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 */#include "mycrypt.h"#ifdef OFBint ofb_start(int cipher, const unsigned char *IV, const unsigned char *key,               int keylen, int num_rounds, symmetric_OFB *ofb){   int x, err;   _ARGCHK(IV != NULL);   _ARGCHK(key != NULL);   _ARGCHK(ofb != NULL);   if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {      return err;   }   /* copy details */   ofb->cipher = cipher;   ofb->blocklen = cipher_descriptor[cipher].block_length;   for (x = 0; x < ofb->blocklen; x++) {       ofb->IV[x] = IV[x];   }   /* init the cipher */   ofb->padlen = ofb->blocklen;   return cipher_descriptor[cipher].setup(key, keylen, num_rounds, &ofb->key);}#endif