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+/* crypto/aes/aes_cfb.c -*- mode:C; c-file-style: "eay" -*- */
+/* ====================================================================
+ * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
+ *
+ * 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 above 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 acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission. For written permission, please contact
+ * openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ * nor may "OpenSSL" appear in their names without prior written
+ * permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED 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 OpenSSL PROJECT OR
+ * ITS 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.
+ * ====================================================================
+ *
+ */
+/* 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.]
+ */
+
+#ifndef AES_DEBUG
+# ifndef NDEBUG
+# define NDEBUG
+# endif
+#endif
+#include <assert.h>
+
+#include <openssl/aes.h>
+#include "aes_locl.h"
+#include "e_os.h"
+
+/* The input and output encrypted as though 128bit cfb mode is being
+ * used. The extra state information to record how much of the
+ * 128bit block we have used is contained in *num;
+ */
+
+void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
+ const unsigned long length, const AES_KEY *key,
+ unsigned char *ivec, int *num, const int enc) {
+
+ unsigned int n;
+ unsigned long l = length;
+ unsigned char c;
+
+ assert(in && out && key && ivec && num);
+
+ n = *num;
+
+ if (enc) {
+ while (l--) {
+ if (n == 0) {
+ AES_encrypt(ivec, ivec, key);
+ }
+ ivec[n] = *(out++) = *(in++) ^ ivec[n];
+ n = (n+1) % AES_BLOCK_SIZE;
+ }
+ } else {
+ while (l--) {
+ if (n == 0) {
+ AES_encrypt(ivec, ivec, key);
+ }
+ c = *(in);
+ *(out++) = *(in++) ^ ivec[n];
+ ivec[n] = c;
+ n = (n+1) % AES_BLOCK_SIZE;
+ }
+ }
+
+ *num=n;
+}
+
+/* This expects a single block of size nbits for both in and out. Note that
+ it corrupts any extra bits in the last byte of out */
+void AES_cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
+ const int nbits,const AES_KEY *key,
+ unsigned char *ivec,const int enc)
+ {
+ int n,rem,num;
+ unsigned char ovec[AES_BLOCK_SIZE*2];
+
+ if (nbits<=0 || nbits>128) return;
+
+ /* fill in the first half of the new IV with the current IV */
+ memcpy(ovec,ivec,AES_BLOCK_SIZE);
+ /* construct the new IV */
+ AES_encrypt(ivec,ivec,key);
+ num = (nbits+7)/8;
+ if (enc) /* encrypt the input */
+ for(n=0 ; n < num ; ++n)
+ out[n] = (ovec[AES_BLOCK_SIZE+n] = in[n] ^ ivec[n]);
+ else /* decrypt the input */
+ for(n=0 ; n < num ; ++n)
+ out[n] = (ovec[AES_BLOCK_SIZE+n] = in[n]) ^ ivec[n];
+ /* shift ovec left... */
+ rem = nbits%8;
+ num = nbits/8;
+ if(rem==0)
+ memcpy(ivec,ovec+num,AES_BLOCK_SIZE);
+ else
+ for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
+ ivec[n] = ovec[n+num]<<rem | ovec[n+num+1]>>(8-rem);
+
+ /* it is not necessary to cleanse ovec, since the IV is not secret */
+ }
+
+/* N.B. This expects the input to be packed, MS bit first */
+void AES_cfb1_encrypt(const unsigned char *in, unsigned char *out,
+ const unsigned long length, const AES_KEY *key,
+ unsigned char *ivec, int *num, const int enc)
+ {
+ unsigned int n;
+ unsigned char c[1],d[1];
+
+ assert(in && out && key && ivec && num);
+ assert(*num == 0);
+
+ memset(out,0,(length+7)/8);
+ for(n=0 ; n < length ; ++n)
+ {
+ c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0;
+ AES_cfbr_encrypt_block(c,d,1,key,ivec,enc);
+ out[n/8]=(out[n/8]&~(1 << (7-n%8)))|((d[0]&0x80) >> (n%8));
+ }
+ }
+
+void AES_cfb8_encrypt(const unsigned char *in, unsigned char *out,
+ const unsigned long length, const AES_KEY *key,
+ unsigned char *ivec, int *num, const int enc)
+ {
+ unsigned int n;
+
+ assert(in && out && key && ivec && num);
+ assert(*num == 0);
+
+ for(n=0 ; n < length ; ++n)
+ AES_cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc);
+ }
+