110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
|
|
/* SPDX-License-Identifier: Unlicense */
|
|
#include "tomcrypt_private.h"
|
|
|
|
/**
|
|
@file lrw_process.c
|
|
LRW_MODE implementation, Encrypt/decrypt blocks, Tom St Denis
|
|
*/
|
|
|
|
#ifdef LTC_LRW_MODE
|
|
|
|
/**
|
|
Process blocks with LRW, since decrypt/encrypt are largely the same they share this code.
|
|
@param pt The "input" data
|
|
@param ct [out] The "output" data
|
|
@param len The length of the input, must be a multiple of 128-bits (16 octets)
|
|
@param mode LRW_ENCRYPT or LRW_DECRYPT
|
|
@param lrw The LRW state
|
|
@return CRYPT_OK if successful
|
|
*/
|
|
int lrw_process(const unsigned char *pt, unsigned char *ct, unsigned long len, int mode, symmetric_LRW *lrw)
|
|
{
|
|
unsigned char prod[16];
|
|
int x, err;
|
|
#ifdef LTC_LRW_TABLES
|
|
int y;
|
|
#endif
|
|
|
|
LTC_ARGCHK(pt != NULL);
|
|
LTC_ARGCHK(ct != NULL);
|
|
LTC_ARGCHK(lrw != NULL);
|
|
|
|
if (len & 15) {
|
|
return CRYPT_INVALID_ARG;
|
|
}
|
|
|
|
while (len) {
|
|
/* copy pad */
|
|
XMEMCPY(prod, lrw->pad, 16);
|
|
|
|
/* increment IV */
|
|
for (x = 15; x >= 0; x--) {
|
|
lrw->IV[x] = (lrw->IV[x] + 1) & 255;
|
|
if (lrw->IV[x]) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* update pad */
|
|
#ifdef LTC_LRW_TABLES
|
|
/* for each byte changed we undo it's affect on the pad then add the new product */
|
|
for (; x < 16; x++) {
|
|
#ifdef LTC_FAST
|
|
for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
|
|
*(LTC_FAST_TYPE_PTR_CAST(lrw->pad + y)) ^= *(LTC_FAST_TYPE_PTR_CAST(&lrw->PC[x][lrw->IV[x]][y])) ^ *(LTC_FAST_TYPE_PTR_CAST(&lrw->PC[x][(lrw->IV[x]-1)&255][y]));
|
|
}
|
|
#else
|
|
for (y = 0; y < 16; y++) {
|
|
lrw->pad[y] ^= lrw->PC[x][lrw->IV[x]][y] ^ lrw->PC[x][(lrw->IV[x]-1)&255][y];
|
|
}
|
|
#endif
|
|
}
|
|
#else
|
|
gcm_gf_mult(lrw->tweak, lrw->IV, lrw->pad);
|
|
#endif
|
|
|
|
/* xor prod */
|
|
#ifdef LTC_FAST
|
|
for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) {
|
|
*(LTC_FAST_TYPE_PTR_CAST(ct + x)) = *(LTC_FAST_TYPE_PTR_CAST(pt + x)) ^ *(LTC_FAST_TYPE_PTR_CAST(prod + x));
|
|
}
|
|
#else
|
|
for (x = 0; x < 16; x++) {
|
|
ct[x] = pt[x] ^ prod[x];
|
|
}
|
|
#endif
|
|
|
|
/* send through cipher */
|
|
if (mode == LRW_ENCRYPT) {
|
|
if ((err = ecb_encrypt_block(ct, ct, &lrw->ecb)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
} else {
|
|
if ((err = ecb_decrypt_block(ct, ct, &lrw->ecb)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
}
|
|
|
|
/* xor prod */
|
|
#ifdef LTC_FAST
|
|
for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) {
|
|
*(LTC_FAST_TYPE_PTR_CAST(ct + x)) = *(LTC_FAST_TYPE_PTR_CAST(ct + x)) ^ *(LTC_FAST_TYPE_PTR_CAST(prod + x));
|
|
}
|
|
#else
|
|
for (x = 0; x < 16; x++) {
|
|
ct[x] = ct[x] ^ prod[x];
|
|
}
|
|
#endif
|
|
|
|
/* move to next */
|
|
pt += 16;
|
|
ct += 16;
|
|
len -= 16;
|
|
}
|
|
|
|
return CRYPT_OK;
|
|
}
|
|
|
|
#endif
|