Mercurial > dropbear
diff src/modes/ecb/ecb_decrypt.c @ 191:1c15b283127b libtomcrypt-orig
Import of libtomcrypt 1.02 with manual path rename rearrangement etc
author | Matt Johnston <matt@ucc.asn.au> |
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date | Fri, 06 May 2005 13:23:02 +0000 |
parents | |
children | 39d5d58461d6 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/modes/ecb/ecb_decrypt.c Fri May 06 13:23:02 2005 +0000 @@ -0,0 +1,55 @@ +/* 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.org + */ +#include "tomcrypt.h" + +/** + @file ecb_decrypt.c + ECB implementation, decrypt a block, Tom St Denis +*/ + +#ifdef ECB + +/** + ECB decrypt + @param ct Ciphertext + @param pt [out] Plaintext + @param len The number of octets to process (must be multiple of the cipher block size) + @param ecb ECB state + @return CRYPT_OK if successful +*/ +int ecb_decrypt(const unsigned char *ct, unsigned char *pt, unsigned long len, symmetric_ECB *ecb) +{ + int err; + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + LTC_ARGCHK(ecb != NULL); + if ((err = cipher_is_valid(ecb->cipher)) != CRYPT_OK) { + return err; + } + if (len % cipher_descriptor[ecb->cipher].block_length) { + return CRYPT_INVALID_ARG; + } + + /* check for accel */ + if (cipher_descriptor[ecb->cipher].accel_ecb_decrypt != NULL) { + cipher_descriptor[ecb->cipher].accel_ecb_decrypt(ct, pt, len / cipher_descriptor[ecb->cipher].block_length, &ecb->key); + } else { + while (len) { + cipher_descriptor[ecb->cipher].ecb_decrypt(ct, pt, &ecb->key); + pt += cipher_descriptor[ecb->cipher].block_length; + ct += cipher_descriptor[ecb->cipher].block_length; + len -= cipher_descriptor[ecb->cipher].block_length; + } + } + return CRYPT_OK; +} + +#endif