1 /* 2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (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 /* 13 * The input and output encrypted as though 64bit cfb mode is being used. 14 * The extra state information to record how much of the 64bit block we have 15 * used is contained in *num; 16 */ 17 18 void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out, 19 long length, DES_key_schedule *schedule, 20 DES_cblock *ivec, int *num, int enc) 21 { 22 register DES_LONG v0, v1; 23 register long l = length; 24 register int n = *num; 25 DES_LONG ti[2]; 26 unsigned char *iv, c, cc; 27 28 iv = &(*ivec)[0]; 29 if (enc) { 30 while (l--) { 31 if (n == 0) { 32 c2l(iv, v0); 33 ti[0] = v0; 34 c2l(iv, v1); 35 ti[1] = v1; 36 DES_encrypt1(ti, schedule, DES_ENCRYPT); 37 iv = &(*ivec)[0]; 38 v0 = ti[0]; 39 l2c(v0, iv); 40 v0 = ti[1]; 41 l2c(v0, iv); 42 iv = &(*ivec)[0]; 43 } 44 c = *(in++) ^ iv[n]; 45 *(out++) = c; 46 iv[n] = c; 47 n = (n + 1) & 0x07; 48 } 49 } else { 50 while (l--) { 51 if (n == 0) { 52 c2l(iv, v0); 53 ti[0] = v0; 54 c2l(iv, v1); 55 ti[1] = v1; 56 DES_encrypt1(ti, schedule, DES_ENCRYPT); 57 iv = &(*ivec)[0]; 58 v0 = ti[0]; 59 l2c(v0, iv); 60 v0 = ti[1]; 61 l2c(v0, iv); 62 iv = &(*ivec)[0]; 63 } 64 cc = *(in++); 65 c = iv[n]; 66 iv[n] = cc; 67 *(out++) = c ^ cc; 68 n = (n + 1) & 0x07; 69 } 70 } 71 v0 = v1 = ti[0] = ti[1] = c = cc = 0; 72 *num = n; 73 } 74