/* 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://libtomcrypt.com */#include "tomcrypt.h"/**  @file cfb_encrypt.c  CFB implementation, encrypt data, Tom St Denis*/#ifdef LTC_CFB_MODE/**  CFB encrypt  @param pt     Plaintext  @param ct     [out] Ciphertext  @param len    Length of plaintext (octets)  @param cfb    CFB state  @return CRYPT_OK if successful*/int cfb_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_CFB *cfb){   int err;   LTC_ARGCHK(pt != NULL);   LTC_ARGCHK(ct != NULL);   LTC_ARGCHK(cfb != NULL);   if ((err = cipher_is_valid(cfb->cipher)) != CRYPT_OK) {       return err;   }   /* is blocklen/padlen valid? */   if (cfb->blocklen < 0 || cfb->blocklen > (int)sizeof(cfb->IV) ||       cfb->padlen   < 0 || cfb->padlen   > (int)sizeof(cfb->pad)) {      return CRYPT_INVALID_ARG;   }   while (len-- > 0) {       if (cfb->padlen == cfb->blocklen) {          if ((err = cipher_descriptor[cfb->cipher].ecb_encrypt(cfb->pad, cfb->IV, &cfb->key)) != CRYPT_OK) {             return err;          }          cfb->padlen = 0;       }       cfb->pad[cfb->padlen] = (*ct = *pt ^ cfb->IV[cfb->padlen]);       ++pt;        ++ct;       ++(cfb->padlen);   }   return CRYPT_OK;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/modes/cfb/cfb_encrypt.c,v $ *//* $Revision: 1.7 $ *//* $Date: 2006/11/26 01:45:14 $ */