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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, tomstdenis@gmail.com, http://libtom.org
*/
#include "tomcrypt.h"
/**
@file ecb_decrypt.c
ECB implementation, decrypt a block, Tom St Denis
*/
#ifdef LTC_ECB_MODE
/**
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) {
return cipher_descriptor[ecb->cipher].accel_ecb_decrypt(ct, pt, len / cipher_descriptor[ecb->cipher].block_length, &ecb->key);
} else {
while (len) {
if ((err = cipher_descriptor[ecb->cipher].ecb_decrypt(ct, pt, &ecb->key)) != CRYPT_OK) {
return err;
}
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
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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