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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://libtomcrypt.com
*/
#include "tomcrypt.h"
/**
@file f8_encrypt.c
F8 implementation, encrypt data, Tom St Denis
*/
#ifdef LTC_F8_MODE
/**
F8 encrypt
@param pt Plaintext
@param ct [out] Ciphertext
@param len Length of plaintext (octets)
@param f8 F8 state
@return CRYPT_OK if successful
*/
int f8_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_F8 *f8)
{
int err, x;
unsigned char buf[MAXBLOCKSIZE];
LTC_ARGCHK(pt != NULL);
LTC_ARGCHK(ct != NULL);
LTC_ARGCHK(f8 != NULL);
if ((err = cipher_is_valid(f8->cipher)) != CRYPT_OK) {
return err;
}
/* is blocklen/padlen valid? */
if (f8->blocklen < 0 || f8->blocklen > (int)sizeof(f8->IV) ||
f8->padlen < 0 || f8->padlen > (int)sizeof(f8->IV)) {
return CRYPT_INVALID_ARG;
}
zeromem(buf, sizeof(buf));
/* make sure the pad is empty */
if (f8->padlen == f8->blocklen) {
/* xor of IV, MIV and blockcnt == what goes into cipher */
STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
++(f8->blockcnt);
for (x = 0; x < f8->blocklen; x++) {
f8->IV[x] ^= f8->MIV[x] ^ buf[x];
}
if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
return err;
}
f8->padlen = 0;
}
#ifdef LTC_FAST
if (f8->padlen == 0) {
while (len >= (unsigned long)f8->blocklen) {
STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
++(f8->blockcnt);
for (x = 0; x < f8->blocklen; x += sizeof(LTC_FAST_TYPE)) {
*((LTC_FAST_TYPE*)(&ct[x])) = *((LTC_FAST_TYPE*)(&pt[x])) ^ *((LTC_FAST_TYPE*)(&f8->IV[x]));
*((LTC_FAST_TYPE*)(&f8->IV[x])) ^= *((LTC_FAST_TYPE*)(&f8->MIV[x])) ^ *((LTC_FAST_TYPE*)(&buf[x]));
}
if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
return err;
}
len -= x;
pt += x;
ct += x;
}
}
#endif
while (len > 0) {
if (f8->padlen == f8->blocklen) {
/* xor of IV, MIV and blockcnt == what goes into cipher */
STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
++(f8->blockcnt);
for (x = 0; x < f8->blocklen; x++) {
f8->IV[x] ^= f8->MIV[x] ^ buf[x];
}
if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
return err;
}
f8->padlen = 0;
}
*ct++ = *pt++ ^ f8->IV[f8->padlen++];
--len;
}
return CRYPT_OK;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/modes/f8/f8_encrypt.c,v $ */
/* $Revision: 1.6 $ */
/* $Date: 2006/11/05 04:16:32 $ */
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