crypto/des/pcbc_enc.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include "des_local.h"
  11
  12 void DES_pcbc_encrypt(const unsigned char *input, unsigned char *output,
  13                       long length, DES_key_schedule *schedule,
  14                       DES_cblock *ivec, int enc)
  15 {
  16     register DES_LONG sin0, sin1, xor0, xor1, tout0, tout1;
  17     DES_LONG tin[2];
  18     const unsigned char *in;
  19     unsigned char *out, *iv;
  20
  21     in = input;
  22     out = output;
  23     iv = &(*ivec)[0];
  24
  25     if (enc) {
  26         c2l(iv, xor0);
  27         c2l(iv, xor1);
  28         for (; length > 0; length -= 8) {
  29             if (length >= 8) {
  30                 c2l(in, sin0);
  31                 c2l(in, sin1);
  32             } else
  33                 c2ln(in, sin0, sin1, length);
  34             tin[0] = sin0 ^ xor0;
  35             tin[1] = sin1 ^ xor1;
  36             DES_encrypt1((DES_LONG *)tin, schedule, DES_ENCRYPT);
  37             tout0 = tin[0];
  38             tout1 = tin[1];
  39             xor0 = sin0 ^ tout0;
  40             xor1 = sin1 ^ tout1;
  41             l2c(tout0, out);
  42             l2c(tout1, out);
  43         }
  44     } else {
  45         c2l(iv, xor0);
  46         c2l(iv, xor1);
  47         for (; length > 0; length -= 8) {
  48             c2l(in, sin0);
  49             c2l(in, sin1);
  50             tin[0] = sin0;
  51             tin[1] = sin1;
  52             DES_encrypt1((DES_LONG *)tin, schedule, DES_DECRYPT);
  53             tout0 = tin[0] ^ xor0;
  54             tout1 = tin[1] ^ xor1;
  55             if (length >= 8) {
  56                 l2c(tout0, out);
  57                 l2c(tout1, out);
  58             } else
  59                 l2cn(tout0, tout1, out, length);
  60             xor0 = tout0 ^ sin0;
  61             xor1 = tout1 ^ sin1;
  62         }
  63     }
  64     tin[0] = tin[1] = 0;
  65     sin0 = sin1 = xor0 = xor1 = tout0 = tout1 = 0;
  66 }