/* 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" /* 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 */ /* Untested, once it is working, it will be optimised */ 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; unsigned char ovec[AES_BLOCK_SIZE*2]; assert(in && out && key && ivec); if(enc) { /* construct the new IV */ AES_encrypt(ivec,ovec,key); /* encrypt the input */ for(n=0 ; n < (nbits+7)/8 ; ++n) out[n]=in[n]^ovec[n]; /* fill in the first half of the new IV with the current IV */ memcpy(ovec,ivec,AES_BLOCK_SIZE); /* and put the ciphertext in the second half */ memcpy(ovec+AES_BLOCK_SIZE,out,(nbits+7)/8); /* shift ovec left most of the bits... */ memmove(ovec,ovec+nbits/8,AES_BLOCK_SIZE+(nbits%8 ? 1 : 0)); /* now the remaining bits */ if(nbits%8 != 0) for(n=0 ; n < AES_BLOCK_SIZE ; ++n) { ovec[n]<<=nbits%8; ovec[n]|=ovec[n+1]>>(8-nbits%8); } /* finally, move it back into place */ memcpy(ivec,ovec,AES_BLOCK_SIZE); } else { /* construct the new IV in the first half of ovec */ AES_encrypt(ivec,ovec,key); /* decrypt the input */ for(n=0 ; n < (nbits+7)/8 ; ++n) out[n]=in[n]^ovec[n]; /* fill in the first half of the new IV with the current IV */ memcpy(ovec,ivec,AES_BLOCK_SIZE); /* append the ciphertext */ memcpy(ovec+AES_BLOCK_SIZE,in,(nbits+7)/8); /* shift ovec left most of the bits... */ memmove(ovec,ovec+nbits/8,AES_BLOCK_SIZE+(nbits%8 ? 1 : 0)); /* now the remaining bits */ if(nbits%8 != 0) for(n=0 ; n < AES_BLOCK_SIZE ; ++n) { ovec[n]<<=nbits%8; ovec[n]|=ovec[n+1]>>(8-nbits%8); } /* finally, move it back into place */ memcpy(ivec,ovec,AES_BLOCK_SIZE); } /* 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); }

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