lib/crypto/aes.c

   1 /*
   2  * Copyright (c) 2003 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "replace.h"
  35
  36 #include "rijndael-alg-fst.h"
  37 #include "aes.h"
  38
  39 int
  40 AES_set_encrypt_key(const unsigned char *userkey, const int bits, AES_KEY *key)
  41 {
  42     key->rounds = rijndaelKeySetupEnc(key->key, userkey, bits);
  43     if (key->rounds == 0)
  44         return -1;
  45     return 0;
  46 }
  47
  48 int
  49 AES_set_decrypt_key(const unsigned char *userkey, const int bits, AES_KEY *key)
  50 {
  51     key->rounds = rijndaelKeySetupDec(key->key, userkey, bits);
  52     if (key->rounds == 0)
  53         return -1;
  54     return 0;
  55 }
  56
  57 void
  58 AES_encrypt(const unsigned char *in, unsigned char *out, const AES_KEY *key)
  59 {
  60     rijndaelEncrypt(key->key, key->rounds, in, out);
  61 }
  62
  63 void
  64 AES_decrypt(const unsigned char *in, unsigned char *out, const AES_KEY *key)
  65 {
  66     rijndaelDecrypt(key->key, key->rounds, in, out);
  67 }
  68
  69 void
  70 AES_cbc_encrypt(const unsigned char *in, unsigned char *out,
  71                 unsigned long size, const AES_KEY *key,
  72                 unsigned char *iv, int forward_encrypt)
  73 {
  74     unsigned char tmp[AES_BLOCK_SIZE];
  75     int i;
  76
  77     if (forward_encrypt) {
  78         while (size >= AES_BLOCK_SIZE) {
  79             for (i = 0; i < AES_BLOCK_SIZE; i++)
  80                 tmp[i] = in[i] ^ iv[i];
  81             AES_encrypt(tmp, out, key);
  82             memcpy(iv, out, AES_BLOCK_SIZE);
  83             size -= AES_BLOCK_SIZE;
  84             in += AES_BLOCK_SIZE;
  85             out += AES_BLOCK_SIZE;
  86         }
  87         if (size) {
  88             for (i = 0; i < size; i++)
  89                 tmp[i] = in[i] ^ iv[i];
  90             for (i = size; i < AES_BLOCK_SIZE; i++)
  91                 tmp[i] = iv[i];
  92             AES_encrypt(tmp, out, key);
  93             memcpy(iv, out, AES_BLOCK_SIZE);
  94         }
  95     } else {
  96         while (size >= AES_BLOCK_SIZE) {
  97             memcpy(tmp, in, AES_BLOCK_SIZE);
  98             AES_decrypt(tmp, out, key);
  99             for (i = 0; i < AES_BLOCK_SIZE; i++)
 100                 out[i] ^= iv[i];
 101             memcpy(iv, tmp, AES_BLOCK_SIZE);
 102             size -= AES_BLOCK_SIZE;
 103             in += AES_BLOCK_SIZE;
 104             out += AES_BLOCK_SIZE;
 105         }
 106         if (size) {
 107             memcpy(tmp, in, AES_BLOCK_SIZE);
 108             AES_decrypt(tmp, out, key);
 109             for (i = 0; i < size; i++)
 110                 out[i] ^= iv[i];
 111             memcpy(iv, tmp, AES_BLOCK_SIZE);
 112         }
 113     }
 114 }