Mercurial > dropbear
view libtomcrypt/src/modes/cfb/cfb_decrypt.c @ 436:7282370416a0
Improve known_hosts checking.
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Thu, 22 Feb 2007 15:29:32 +0000 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
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/* 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, [email protected], http://libtomcrypt.com */ #include "tomcrypt.h" /** @file cfb_decrypt.c CFB implementation, decrypt data, Tom St Denis */ #ifdef LTC_CFB_MODE /** CFB decrypt @param ct Ciphertext @param pt [out] Plaintext @param len Length of ciphertext (octets) @param cfb CFB state @return CRYPT_OK if successful */ int cfb_decrypt(const unsigned char *ct, unsigned char *pt, 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 = *ct ^ cfb->IV[cfb->padlen]; ++pt; ++ct; ++(cfb->padlen); } return CRYPT_OK; } #endif /* $Source: /cvs/libtom/libtomcrypt/src/modes/cfb/cfb_decrypt.c,v $ */ /* $Revision: 1.7 $ */ /* $Date: 2006/11/26 01:45:14 $ */