63 lines
1.6 KiB
C
63 lines
1.6 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 pmac_done.c
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PMAC implementation, terminate a session, by Tom St Denis
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*/
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#ifdef LTC_PMAC
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int pmac_done(pmac_state *pmac, unsigned char *out, unsigned long *outlen)
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{
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int err, x;
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LTC_ARGCHK(pmac != NULL);
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LTC_ARGCHK(out != NULL);
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if ((err = cipher_is_valid(pmac->cipher_idx)) != CRYPT_OK) {
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return err;
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}
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if ((pmac->buflen > (int)sizeof(pmac->block)) || (pmac->buflen < 0) ||
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(pmac->block_len > (int)sizeof(pmac->block)) || (pmac->buflen > pmac->block_len)) {
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return CRYPT_INVALID_ARG;
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}
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/* handle padding. If multiple xor in L/x */
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if (pmac->buflen == pmac->block_len) {
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/* xor Lr against the checksum */
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for (x = 0; x < pmac->block_len; x++) {
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pmac->checksum[x] ^= pmac->block[x] ^ pmac->Lr[x];
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}
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} else {
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/* otherwise xor message bytes then the 0x80 byte */
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for (x = 0; x < pmac->buflen; x++) {
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pmac->checksum[x] ^= pmac->block[x];
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}
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pmac->checksum[x] ^= 0x80;
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}
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/* encrypt it */
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if ((err = cipher_descriptor[pmac->cipher_idx].ecb_encrypt(pmac->checksum, pmac->checksum, &pmac->key)) != CRYPT_OK) {
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return err;
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}
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cipher_descriptor[pmac->cipher_idx].done(&pmac->key);
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/* store it */
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for (x = 0; x < pmac->block_len && x < (int)*outlen; x++) {
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out[x] = pmac->checksum[x];
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}
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*outlen = x;
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#ifdef LTC_CLEAN_STACK
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zeromem(pmac, sizeof(*pmac));
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#endif
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return CRYPT_OK;
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}
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#endif
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