crypto/idea/i_cfb64.c

   1 /*
   2  * Copyright 1995-2020 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 /*
  11  * IDEA low level APIs are deprecated for public use, but still ok for internal
  12  * use where we're using them to implement the higher level EVP interface, as is
  13  * the case here.
  14  */
  15 #include "internal/deprecated.h"
  16
  17 #include <openssl/idea.h>
  18 #include "idea_local.h"
  19
  20 /*
  21  * The input and output encrypted as though 64bit cfb mode is being used.
  22  * The extra state information to record how much of the 64bit block we have
  23  * used is contained in *num;
  24  */
  25
  26 void IDEA_cfb64_encrypt(const unsigned char *in, unsigned char *out,
  27                         long length, IDEA_KEY_SCHEDULE *schedule,
  28                         unsigned char *ivec, int *num, int encrypt)
  29 {
  30     register unsigned long v0, v1, t;
  31     register int n = *num;
  32     register long l = length;
  33     unsigned long ti[2];
  34     unsigned char *iv, c, cc;
  35
  36     if (n < 0) {
  37         *num = -1;
  38         return;
  39     }
  40
  41     iv = (unsigned char *)ivec;
  42     if (encrypt) {
  43         while (l--) {
  44             if (n == 0) {
  45                 n2l(iv, v0);
  46                 ti[0] = v0;
  47                 n2l(iv, v1);
  48                 ti[1] = v1;
  49                 IDEA_encrypt((unsigned long *)ti, schedule);
  50                 iv = (unsigned char *)ivec;
  51                 t = ti[0];
  52                 l2n(t, iv);
  53                 t = ti[1];
  54                 l2n(t, iv);
  55                 iv = (unsigned char *)ivec;
  56             }
  57             c = *(in++) ^ iv[n];
  58             *(out++) = c;
  59             iv[n] = c;
  60             n = (n + 1) & 0x07;
  61         }
  62     } else {
  63         while (l--) {
  64             if (n == 0) {
  65                 n2l(iv, v0);
  66                 ti[0] = v0;
  67                 n2l(iv, v1);
  68                 ti[1] = v1;
  69                 IDEA_encrypt((unsigned long *)ti, schedule);
  70                 iv = (unsigned char *)ivec;
  71                 t = ti[0];
  72                 l2n(t, iv);
  73                 t = ti[1];
  74                 l2n(t, iv);
  75                 iv = (unsigned char *)ivec;
  76             }
  77             cc = *(in++);
  78             c = iv[n];
  79             iv[n] = cc;
  80             *(out++) = c ^ cc;
  81             n = (n + 1) & 0x07;
  82         }
  83     }
  84     v0 = v1 = ti[0] = ti[1] = t = c = cc = 0;
  85     *num = n;
  86 }