workbench/network/WirelessManager/src/crypto/aes-ctr.c

   1 /*
   2  * AES-128 CTR
   3  *
   4  * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Alternatively, this software may be distributed under the terms of BSD
  11  * license.
  12  *
  13  * See README and COPYING for more details.
  14  */
  15
  16 #include "includes.h"
  17
  18 #include "common.h"
  19 #include "aes.h"
  20 #include "aes_wrap.h"
  21
  22 /**
  23  * aes_128_ctr_encrypt - AES-128 CTR mode encryption
  24  * @key: Key for encryption (16 bytes)
  25  * @nonce: Nonce for counter mode (16 bytes)
  26  * @data: Data to encrypt in-place
  27  * @data_len: Length of data in bytes
  28  * Returns: 0 on success, -1 on failure
  29  */
  30 int aes_128_ctr_encrypt(const u8 *key, const u8 *nonce,
  31                         u8 *data, size_t data_len)
  32 {
  33         void *ctx;
  34         size_t j, len, left = data_len;
  35         int i;
  36         u8 *pos = data;
  37         u8 counter[AES_BLOCK_SIZE], buf[AES_BLOCK_SIZE];
  38
  39         ctx = aes_encrypt_init(key, 16);
  40         if (ctx == NULL)
  41                 return -1;
  42         os_memcpy(counter, nonce, AES_BLOCK_SIZE);
  43
  44         while (left > 0) {
  45                 aes_encrypt(ctx, counter, buf);
  46
  47                 len = (left < AES_BLOCK_SIZE) ? left : AES_BLOCK_SIZE;
  48                 for (j = 0; j < len; j++)
  49                         pos[j] ^= buf[j];
  50                 pos += len;
  51                 left -= len;
  52
  53                 for (i = AES_BLOCK_SIZE - 1; i >= 0; i--) {
  54                         counter[i]++;
  55                         if (counter[i])
  56                                 break;
  57                 }
  58         }
  59         aes_encrypt_deinit(ctx);
  60         return 0;
  61 }