1 /* $OpenBSD: cfb64enc.c,v 1.5 2014/06/12 15:49:28 deraadt Exp $ */ 2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58 59 #include "des_locl.h" 60 61 /* The input and output encrypted as though 64bit cfb mode is being 62 * used. The extra state information to record how much of the 63 * 64bit block we have used is contained in *num; 64 */ 65 66 void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out, 67 long length, DES_key_schedule *schedule, 68 DES_cblock *ivec, int *num, int enc) 69 { 70 DES_LONG v0,v1; 71 long l=length; 72 int n= *num; 73 DES_LONG ti[2]; 74 unsigned char *iv,c,cc; 75 76 iv = &(*ivec)[0]; 77 if (enc) 78 { 79 while (l--) 80 { 81 if (n == 0) 82 { 83 c2l(iv,v0); ti[0]=v0; 84 c2l(iv,v1); ti[1]=v1; 85 DES_encrypt1(ti,schedule,DES_ENCRYPT); 86 iv = &(*ivec)[0]; 87 v0=ti[0]; l2c(v0,iv); 88 v0=ti[1]; l2c(v0,iv); 89 iv = &(*ivec)[0]; 90 } 91 c= *(in++)^iv[n]; 92 *(out++)=c; 93 iv[n]=c; 94 n=(n+1)&0x07; 95 } 96 } 97 else 98 { 99 while (l--) 100 { 101 if (n == 0) 102 { 103 c2l(iv,v0); ti[0]=v0; 104 c2l(iv,v1); ti[1]=v1; 105 DES_encrypt1(ti,schedule,DES_ENCRYPT); 106 iv = &(*ivec)[0]; 107 v0=ti[0]; l2c(v0,iv); 108 v0=ti[1]; l2c(v0,iv); 109 iv = &(*ivec)[0]; 110 } 111 cc= *(in++); 112 c=iv[n]; 113 iv[n]=cc; 114 *(out++)=c^cc; 115 n=(n+1)&0x07; 116 } 117 } 118 v0=v1=ti[0]=ti[1]=c=cc=0; 119 *num=n; 120 } 121 122