250 lines
9.3 KiB
C
250 lines
9.3 KiB
C
/* crypto/aes/aes_cfb.c -*- mode:C; c-file-style: "eay" -*- */
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/* ====================================================================
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* Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
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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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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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*/
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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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#ifndef AES_DEBUG
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# ifndef NDEBUG
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# define NDEBUG
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# endif
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#endif
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#include <assert.h>
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#include <openssl/aes.h>
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#include "aes_locl.h"
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/* The input and output encrypted as though 128bit cfb mode is being
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* used. The extra state information to record how much of the
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* 128bit block we have used is contained in *num;
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*/
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void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
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const unsigned long length, const AES_KEY *key,
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unsigned char *ivec, int *num, const int enc) {
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unsigned int n;
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unsigned long l = length;
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unsigned char c;
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assert(in && out && key && ivec && num);
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n = *num;
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if (enc) {
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while (l--) {
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if (n == 0) {
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AES_encrypt(ivec, ivec, key);
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}
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ivec[n] = *(out++) = *(in++) ^ ivec[n];
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n = (n+1) % AES_BLOCK_SIZE;
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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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AES_encrypt(ivec, ivec, key);
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}
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c = *(in);
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*(out++) = *(in++) ^ ivec[n];
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ivec[n] = c;
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n = (n+1) % AES_BLOCK_SIZE;
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}
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}
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*num=n;
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}
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/* This expects a single block of size nbits for both in and out. Note that
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it corrupts any extra bits in the last byte of out */
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/* Untested, once it is working, it will be optimised */
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void AES_cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
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const int nbits,const AES_KEY *key,
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unsigned char *ivec,const int enc)
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{
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int n;
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unsigned char ovec[AES_BLOCK_SIZE*2];
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assert(in && out && key && ivec);
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if(enc)
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{
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/* construct the new IV */
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AES_encrypt(ivec,ovec,key);
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/* encrypt the input */
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for(n=0 ; n < (nbits+7)/8 ; ++n)
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out[n]=in[n]^ovec[n];
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/* fill in the first half of the new IV with the current IV */
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memcpy(ovec,ivec,AES_BLOCK_SIZE);
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/* and put the ciphertext in the second half */
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memcpy(ovec+AES_BLOCK_SIZE,out,(nbits+7)/8);
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/* shift ovec left most of the bits... */
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memmove(ovec,ovec+nbits/8,AES_BLOCK_SIZE+(nbits%8 ? 1 : 0));
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/* now the remaining bits */
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if(nbits%8 != 0)
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for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
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{
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ovec[n]<<=nbits%8;
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ovec[n]|=ovec[n+1]>>(8-nbits%8);
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}
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/* finally, move it back into place */
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memcpy(ivec,ovec,AES_BLOCK_SIZE);
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}
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else
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{
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/* construct the new IV in the first half of ovec */
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AES_encrypt(ivec,ovec,key);
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/* decrypt the input */
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for(n=0 ; n < (nbits+7)/8 ; ++n)
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out[n]=in[n]^ovec[n];
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/* fill in the first half of the new IV with the current IV */
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memcpy(ovec,ivec,AES_BLOCK_SIZE);
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/* append the ciphertext */
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memcpy(ovec+AES_BLOCK_SIZE,in,(nbits+7)/8);
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/* shift ovec left most of the bits... */
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memmove(ovec,ovec+nbits/8,AES_BLOCK_SIZE+(nbits%8 ? 1 : 0));
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/* now the remaining bits */
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if(nbits%8 != 0)
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for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
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{
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ovec[n]<<=nbits%8;
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ovec[n]|=ovec[n+1]>>(8-nbits%8);
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}
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/* finally, move it back into place */
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memcpy(ivec,ovec,AES_BLOCK_SIZE);
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}
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/* it is not necessary to cleanse ovec, since the IV is not secret */
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}
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/* N.B. This expects the input to be packed, MS bit first */
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void AES_cfb1_encrypt(const unsigned char *in, unsigned char *out,
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const unsigned long length, const AES_KEY *key,
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unsigned char *ivec, int *num, const int enc)
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{
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unsigned int n;
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unsigned char c[1],d[1];
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assert(in && out && key && ivec && num);
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assert(*num == 0);
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memset(out,0,(length+7)/8);
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for(n=0 ; n < length ; ++n)
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{
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c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0;
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AES_cfbr_encrypt_block(c,d,1,key,ivec,enc);
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out[n/8]=(out[n/8]&~(1 << (7-n%8)))|((d[0]&0x80) >> (n%8));
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}
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}
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void AES_cfb8_encrypt(const unsigned char *in, unsigned char *out,
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const unsigned long length, const AES_KEY *key,
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unsigned char *ivec, int *num, const int enc)
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{
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unsigned int n;
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assert(in && out && key && ivec && num);
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assert(*num == 0);
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for(n=0 ; n < length ; ++n)
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AES_cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc);
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}
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