ncbc_enc.c

3des加解密算法实现

/* crypto/des/ncbc_enc.c */
/*
* #included by:
* cbc_enc.c (DES_cbc_encrypt)
* des_enc.c (DES_ncbc_encrypt)
*/
/* Copyright (C) 1995-1998 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 "des_locl.h"

#ifdef CBC_ENC_C__DONT_UPDATE_IV
void DES_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
DES_key_schedule *_schedule, DES_cblock *ivec, int enc)
#else
void DES_ncbc_encrypt(const unsigned char *in, unsigned char *out, long length,
DES_key_schedule *_schedule, DES_cblock *ivec, int enc)
#endif
{
register DES_LONG tin0,tin1;
register DES_LONG tout0,tout1,xor0,xor1;
register long l=length;
DES_LONG tin[2];
unsigned char *iv;

iv = &amt;(*ivec)[0];

if (enc)
{
c2l(iv,tout0);
c2l(iv,tout1);
for (l-=8; l>=0; l-=8)
{
c2l(in,tin0);
c2l(in,tin1);
tin0^=tout0; tin[0]=tin0;
tin1^=tout1; tin[1]=tin1;
DES_encrypt1((DES_LONG *)tin,_schedule,DES_ENCRYPT);
tout0=tin[0]; l2c(tout0,out);
tout1=tin[1]; l2c(tout1,out);
}
if (l != -8)
{
c2ln(in,tin0,tin1,l+8);
tin0^=tout0; tin[0]=tin0;
tin1^=tout1; tin[1]=tin1;
DES_encrypt1((DES_LONG *)tin,_schedule,DES_ENCRYPT);
tout0=tin[0]; l2c(tout0,out);
tout1=tin[1]; l2c(tout1,out);
}
#ifndef CBC_ENC_C__DONT_UPDATE_IV
iv = &amt;(*ivec)[0];
l2c(tout0,iv);
l2c(tout1,iv);
#endif
}
else
{
c2l(iv,xor0);
c2l(iv,xor1);
for (l-=8; l>=0; l-=8)
{
c2l(in,tin0); tin[0]=tin0;
c2l(in,tin1); tin[1]=tin1;
DES_encrypt1((DES_LONG *)tin,_schedule,DES_DECRYPT);
tout0=tin[0]^xor0;
tout1=tin[1]^xor1;
l2c(tout0,out);
l2c(tout1,out);
xor0=tin0;
xor1=tin1;
}
if (l != -8)
{
c2l(in,tin0); tin[0]=tin0;
c2l(in,tin1); tin[1]=tin1;
DES_encrypt1((DES_LONG *)tin,_schedule,DES_DECRYPT);
tout0=tin[0]^xor0;
tout1=tin[1]^xor1;
l2cn(tout0,tout1,out,l+8);
#ifndef CBC_ENC_C__DONT_UPDATE_IV
xor0=tin0;
xor1=tin1;
#endif
}
#ifndef CBC_ENC_C__DONT_UPDATE_IV 
iv = &amt;(*ivec)[0];
l2c(xor0,iv);
l2c(xor1,iv);
#endif
}
tin0=tin1=tout0=tout1=xor0=xor1=0;
tin[0]=tin[1]=0;
}