bf_cbc.cpp

这是一个blowfish加密算法。该算法是从speakfs提取

/* crypto/bf/bf_cbc.c */
/* Copyright (C) 1995-1997 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * 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 ([e-mail]).
 * 
 * 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 ([e-mail])"
 *    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 ([e-mail])"
 * 
 * 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 "blowfish.h"
#include "bf_locl.h"

void BF_cbc_encrypt(unsigned char *in, unsigned char *out,long length, BF_KEY *ks, unsigned char *iv, int encrypt)
//unsigned char *in;
//unsigned char *out;
//long length;
//BF_KEY *ks;
//unsigned char *iv;
//int encrypt;
        {
        register BF_LONG tin0,tin1;
        register BF_LONG tout0,tout1,xor0,xor1;
        register long l=length;
        BF_LONG tin[2];

        if (encrypt)
                {
                n2l(iv,tout0);
                n2l(iv,tout1);
                iv-=8;
                for (l-=8; l>=0; l-=8)
                        {
                        n2l(in,tin0);
                        n2l(in,tin1);
                        tin0^=tout0;
                        tin1^=tout1;
                        tin[0]=tin0;
                        tin[1]=tin1;
                        BF_encrypt(tin,ks,BF_ENCRYPT);
                        tout0=tin[0];
                        tout1=tin[1];
                        l2n(tout0,out);
                        l2n(tout1,out);
                        }
                if (l != -8)
                        {
                        n2ln(in,tin0,tin1,l+8);
                        tin0^=tout0;
                        tin1^=tout1;
                        tin[0]=tin0;
                        tin[1]=tin1;
                        BF_encrypt(tin,ks,BF_ENCRYPT);
                        tout0=tin[0];
                        tout1=tin[1];
                        l2n(tout0,out);
                        l2n(tout1,out);
                        }
                l2n(tout0,iv);
                l2n(tout1,iv);
                }
        else
                {
                n2l(iv,xor0);
                n2l(iv,xor1);
                iv-=8;
                for (l-=8; l>=0; l-=8)
                        {
                        n2l(in,tin0);
                        n2l(in,tin1);
                        tin[0]=tin0;
                        tin[1]=tin1;
                        BF_encrypt(tin,ks,BF_DECRYPT);
                        tout0=tin[0]^xor0;
                        tout1=tin[1]^xor1;
                        l2n(tout0,out);
                        l2n(tout1,out);
                        xor0=tin0;
                        xor1=tin1;
                        }
                if (l != -8)
                        {
                        n2l(in,tin0);
                        n2l(in,tin1);
                        tin[0]=tin0;
                        tin[1]=tin1;
                        BF_encrypt(tin,ks,BF_DECRYPT);
                        tout0=tin[0]^xor0;
                        tout1=tin[1]^xor1;
                        l2nn(tout0,tout1,out,l+8);
                        xor0=tin0;
                        xor1=tin1;
                        }
                l2n(xor0,iv);
                l2n(xor1,iv);
                }
        tin0=tin1=tout0=tout1=xor0=xor1=0;
        tin[0]=tin[1]=0;
        }