/* $OpenBSD: cfb_enc.c,v 1.16 2023/07/08 07:11:07 beck Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include "des_local.h" #include /* The input and output are loaded in multiples of 8 bits. * What this means is that if you hame numbits=12 and length=2 * the first 12 bits will be retrieved from the first byte and half * the second. The second 12 bits will come from the 3rd and half the 4th * byte. */ /* Until Aug 1 2003 this function did not correctly implement CFB-r, so it * will not be compatible with any encryption prior to that date. Ben. */ void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits, long length, DES_key_schedule *schedule, DES_cblock *ivec, int enc) { DES_LONG d0, d1, v0, v1; unsigned long l = length; int num = numbits/8, n = (numbits + 7)/8, i, rem = numbits % 8; DES_LONG ti[2]; unsigned char *iv; #if BYTE_ORDER != LITTLE_ENDIAN unsigned char ovec[16]; #else unsigned int sh[4]; unsigned char *ovec = (unsigned char *)sh; #endif if (numbits <= 0 || numbits > 64) return; iv = &(*ivec)[0]; c2l(iv, v0); c2l(iv, v1); if (enc) { while (l >= (unsigned long)n) { l -= n; ti[0] = v0; ti[1] = v1; DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); c2ln(in, d0, d1, n); in += n; d0 ^= ti[0]; d1 ^= ti[1]; l2cn(d0, d1, out, n); out += n; /* 30-08-94 - eay - changed because l>>32 and * l<<32 are bad under gcc :-( */ if (numbits == 32) { v0 = v1; v1 = d0; } else if (numbits == 64) { v0 = d0; v1 = d1; } else { #if BYTE_ORDER != LITTLE_ENDIAN iv = &ovec[0]; l2c(v0, iv); l2c(v1, iv); l2c(d0, iv); l2c(d1, iv); #else sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1; #endif if (rem == 0) memmove(ovec, ovec + num, 8); else for (i = 0; i < 8; ++i) ovec[i] = ovec[i + num] << rem | ovec[i + num + 1] >> (8 - rem); #if BYTE_ORDER == LITTLE_ENDIAN v0 = sh[0], v1 = sh[1]; #else iv = &ovec[0]; c2l(iv, v0); c2l(iv, v1); #endif } } } else { while (l >= (unsigned long)n) { l -= n; ti[0] = v0; ti[1] = v1; DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); c2ln(in, d0, d1, n); in += n; /* 30-08-94 - eay - changed because l>>32 and * l<<32 are bad under gcc :-( */ if (numbits == 32) { v0 = v1; v1 = d0; } else if (numbits == 64) { v0 = d0; v1 = d1; } else { #if BYTE_ORDER != LITTLE_ENDIAN iv = &ovec[0]; l2c(v0, iv); l2c(v1, iv); l2c(d0, iv); l2c(d1, iv); #else sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1; #endif if (rem == 0) memmove(ovec, ovec + num, 8); else for (i = 0; i < 8; ++i) ovec[i] = ovec[i + num] << rem | ovec[i + num + 1] >> (8 - rem); #if BYTE_ORDER == LITTLE_ENDIAN v0 = sh[0], v1 = sh[1]; #else iv = &ovec[0]; c2l(iv, v0); c2l(iv, v1); #endif } d0 ^= ti[0]; d1 ^= ti[1]; l2cn(d0, d1, out, n); out += n; } } iv = &(*ivec)[0]; l2c(v0, iv); l2c(v1, iv); v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0; }