Files
GmSSL/src/zuc_eea.c
Zhi Guan bcad2eb8dd update
2021-09-10 11:29:16 +08:00

50 lines
1.5 KiB
C

/*
* Copyright 2014-2021 The GmSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdlib.h>
#include <gmssl/zuc.h>
static void zuc_set_eea_key(ZUC_KEY *key, const unsigned char user_key[16],
ZUC_UINT32 count, ZUC_UINT5 bearer, ZUC_BIT direction)
{
unsigned char iv[16] = {0};
iv[0] = iv[8] = count >> 24;
iv[1] = iv[9] = count >> 16;
iv[2] = iv[10] = count >> 8;
iv[3] = iv[11] = count;
iv[4] = iv[12] = ((bearer << 1) | (direction & 1)) << 2;
zuc_set_key(key, user_key, iv);
}
void zuc_eea_encrypt(const ZUC_UINT32 *in, ZUC_UINT32 *out, size_t nbits,
const unsigned char key[16], ZUC_UINT32 count, ZUC_UINT5 bearer,
ZUC_BIT direction)
{
ZUC_KEY zuc_key;
size_t nwords = (nbits + 31)/32;
size_t i;
zuc_set_eea_key(&zuc_key, key, count, bearer, direction);
zuc_generate_keystream(&zuc_key, nwords, out);
for (i = 0; i < nwords; i++) {
out[i] ^= in[i];
}
if (nbits % 32 != 0) {
out[nwords - 1] |= (0xffffffff << (32 - (nbits%32)));
}
}