49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
|
|
/* SPDX-License-Identifier: Unlicense */
|
|
#include "tomcrypt_private.h"
|
|
|
|
/**
|
|
@file ofb_encrypt.c
|
|
OFB implementation, encrypt data, Tom St Denis
|
|
*/
|
|
|
|
#ifdef LTC_OFB_MODE
|
|
|
|
/**
|
|
OFB encrypt
|
|
@param pt Plaintext
|
|
@param ct [out] Ciphertext
|
|
@param len Length of plaintext (octets)
|
|
@param ofb OFB state
|
|
@return CRYPT_OK if successful
|
|
*/
|
|
int ofb_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_OFB *ofb)
|
|
{
|
|
int err;
|
|
LTC_ARGCHK(pt != NULL);
|
|
LTC_ARGCHK(ct != NULL);
|
|
LTC_ARGCHK(ofb != NULL);
|
|
if ((err = cipher_is_valid(ofb->ecb.cipher)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
|
|
/* is blocklen/padlen valid? */
|
|
if (ofb->ecb.blocklen < 0 || ofb->ecb.blocklen > (int)sizeof(ofb->IV) ||
|
|
ofb->padlen < 0 || ofb->padlen > (int)sizeof(ofb->IV)) {
|
|
return CRYPT_INVALID_ARG;
|
|
}
|
|
|
|
while (len-- > 0) {
|
|
if (ofb->padlen == ofb->ecb.blocklen) {
|
|
if ((err = ecb_encrypt_block(ofb->IV, ofb->IV, &ofb->ecb)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
ofb->padlen = 0;
|
|
}
|
|
*ct++ = *pt++ ^ ofb->IV[(ofb->padlen)++];
|
|
}
|
|
return CRYPT_OK;
|
|
}
|
|
|
|
#endif
|