124 lines
4.8 KiB
C
124 lines
4.8 KiB
C
/* crypto/cast/c_cfb64.c */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include <openssl/cast.h>
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#include "cast_lcl.h"
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/*
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* The input and output encrypted as though 64bit cfb mode is being used.
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* The extra state information to record how much of the 64bit block we have
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* used is contained in *num;
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*/
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void CAST_cfb64_encrypt(const unsigned char *in, unsigned char *out,
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long length, const CAST_KEY *schedule,
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unsigned char *ivec, int *num, int enc)
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{
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register CAST_LONG v0, v1, t;
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register int n = *num;
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register long l = length;
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CAST_LONG ti[2];
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unsigned char *iv, c, cc;
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iv = ivec;
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if (enc) {
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while (l--) {
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if (n == 0) {
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n2l(iv, v0);
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ti[0] = v0;
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n2l(iv, v1);
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ti[1] = v1;
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CAST_encrypt((CAST_LONG *)ti, schedule);
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iv = ivec;
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t = ti[0];
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l2n(t, iv);
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t = ti[1];
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l2n(t, iv);
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iv = ivec;
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}
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c = *(in++) ^ iv[n];
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*(out++) = c;
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iv[n] = c;
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n = (n + 1) & 0x07;
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}
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} else {
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while (l--) {
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if (n == 0) {
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n2l(iv, v0);
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ti[0] = v0;
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n2l(iv, v1);
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ti[1] = v1;
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CAST_encrypt((CAST_LONG *)ti, schedule);
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iv = ivec;
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t = ti[0];
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l2n(t, iv);
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t = ti[1];
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l2n(t, iv);
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iv = ivec;
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}
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cc = *(in++);
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c = iv[n];
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iv[n] = cc;
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*(out++) = c ^ cc;
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n = (n + 1) & 0x07;
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}
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}
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v0 = v1 = ti[0] = ti[1] = t = c = cc = 0;
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*num = n;
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}
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