92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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/**
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@file f8_encrypt.c
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F8 implementation, encrypt data, Tom St Denis
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*/
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#ifdef LTC_F8_MODE
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/**
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F8 encrypt
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@param pt Plaintext
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@param ct [out] Ciphertext
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@param len Length of plaintext (octets)
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@param f8 F8 state
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@return CRYPT_OK if successful
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*/
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int f8_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_F8 *f8)
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{
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int err, x;
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unsigned char buf[MAXBLOCKSIZE];
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LTC_ARGCHK(pt != NULL);
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LTC_ARGCHK(ct != NULL);
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LTC_ARGCHK(f8 != NULL);
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if ((err = cipher_is_valid(f8->cipher)) != CRYPT_OK) {
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return err;
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}
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/* is blocklen/padlen valid? */
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if (f8->blocklen < 0 || f8->blocklen > (int)sizeof(f8->IV) ||
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f8->padlen < 0 || f8->padlen > (int)sizeof(f8->IV)) {
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return CRYPT_INVALID_ARG;
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}
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zeromem(buf, sizeof(buf));
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/* make sure the pad is empty */
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if (f8->padlen == f8->blocklen) {
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/* xor of IV, MIV and blockcnt == what goes into cipher */
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STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
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++(f8->blockcnt);
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for (x = 0; x < f8->blocklen; x++) {
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f8->IV[x] ^= f8->MIV[x] ^ buf[x];
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}
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if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
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return err;
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}
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f8->padlen = 0;
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}
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#ifdef LTC_FAST
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if (f8->padlen == 0) {
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while (len >= (unsigned long)f8->blocklen) {
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STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
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++(f8->blockcnt);
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for (x = 0; x < f8->blocklen; x += sizeof(LTC_FAST_TYPE)) {
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*(LTC_FAST_TYPE_PTR_CAST(&ct[x])) = *(LTC_FAST_TYPE_PTR_CAST(&pt[x])) ^ *(LTC_FAST_TYPE_PTR_CAST(&f8->IV[x]));
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*(LTC_FAST_TYPE_PTR_CAST(&f8->IV[x])) ^= *(LTC_FAST_TYPE_PTR_CAST(&f8->MIV[x])) ^ *(LTC_FAST_TYPE_PTR_CAST(&buf[x]));
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}
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if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
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return err;
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}
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len -= x;
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pt += x;
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ct += x;
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}
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}
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#endif
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while (len > 0) {
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if (f8->padlen == f8->blocklen) {
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/* xor of IV, MIV and blockcnt == what goes into cipher */
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STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
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++(f8->blockcnt);
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for (x = 0; x < f8->blocklen; x++) {
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f8->IV[x] ^= f8->MIV[x] ^ buf[x];
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}
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if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
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return err;
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}
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f8->padlen = 0;
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}
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*ct++ = *pt++ ^ f8->IV[f8->padlen++];
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--len;
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}
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return CRYPT_OK;
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}
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#endif
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