des_ecb.cpp

DES密码体制的安全性应该不依赖于算法的保密

/* crypto/des/ecb_enc.c */
/* Copyright (C) 1995-1996 Eric Young ([e-mail])
 * All rights reserved.
 */

#include "stdafx.h"

#include "des_locl.h"
#include "spr.h"

char *libdes_version="libdes v 3.24 - 20-Apr-1996 - eay";
char *DES_version="DES part of SSLeay 0.6.4 30-Aug-1996";

char *des_options()
{
	if (sizeof(DES_LONG) != sizeof(long))
		return("des(ptr,int)");
	else
		return("des(ptr,long)");
}

void des_encrypt(DES_LONG *data, des_key_schedule ks, int encrypt)
{
	register DES_LONG l,r,t,u;
	register unsigned char *des_SP=(unsigned char *)des_SPtrans;
	register int i;
	register DES_LONG *s;

	u=data[0];
	r=data[1];

	IP(u,r);
	/* Things have been modified so that the initial rotate is
	 * done outside the loop.  This required the
	 * des_SPtrans values in sp.h to be rotated 1 bit to the right.
	 * One perl script later and things have a 5% speed up on a sparc2.
	 * Thanks to Richard Outerbridge <[e-mail]>
	 * for pointing this out. */
	l=(r<<1)|(r>>31);
	r=(u<<1)|(u>>31);

	/* clear the top bits on machines with 8byte longs */
	l&=0xffffffffL;
	r&=0xffffffffL;

	s=(DES_LONG *)ks;
	/* I don't know if it is worth the effort of loop unrolling the
	 * inner loop
	 */
	if (encrypt)
	{
		for (i=0; i<32; i+=8)
		{
			D_ENCRYPT(l,r,i+0); /*  1 */
			D_ENCRYPT(r,l,i+2); /*  2 */
			D_ENCRYPT(l,r,i+4); /*  3 */
			D_ENCRYPT(r,l,i+6); /*  4 */
		}
	}
	else
	{
		for (i=30; i>0; i-=8)
		{
			D_ENCRYPT(l,r,i-0); /* 16 */
			D_ENCRYPT(r,l,i-2); /* 15 */
			D_ENCRYPT(l,r,i-4); /* 14 */
			D_ENCRYPT(r,l,i-6); /* 13 */
		}
	}
	l=(l>>1)|(l<<31);
	r=(r>>1)|(r<<31);
	/* clear the top bits on machines with 8byte longs */
	l&=0xffffffffL;
	r&=0xffffffffL;

	FP(r,l);
	data[0]=l;
	data[1]=r;
	l=r=t=u=0;
}

void des_ecb_encrypt(des_cblock *input, des_cblock *output, des_key_schedule ks, int encrypt)
{
	register DES_LONG l;
	register unsigned char *in,*out;
	DES_LONG ll[2];

	in=(unsigned char *)input;
	out=(unsigned char *)output;
	c2l(in,l); ll[0]=l;
	c2l(in,l); ll[1]=l;
	des_encrypt(ll,ks,encrypt);
	l=ll[0]; l2c(l,out);
	l=ll[1]; l2c(l,out);
	l=ll[0]=ll[1]=0;
}

void des_encrypt2(DES_LONG *data, des_key_schedule ks, int encrypt)
{
	register DES_LONG l,r,t,u;
	register unsigned char *des_SP=(unsigned char *)des_SPtrans;
	register int i;
	register DES_LONG *s;

	u=data[0];
	r=data[1];

	/* Things have been modified so that the initial rotate is
	 * done outside the loop.  This required the
	 * des_SPtrans values in sp.h to be rotated 1 bit to the right.
	 * One perl script later and things have a 5% speed up on a sparc2.
	 * Thanks to Richard Outerbridge <[e-mail]>
	 * for pointing this out. */
	l=(r<<1)|(r>>31);
	r=(u<<1)|(u>>31);

	/* clear the top bits on machines with 8byte longs */
	l&=0xffffffffL;
	r&=0xffffffffL;

	s=(DES_LONG *)ks;
	/* I don't know if it is worth the effort of loop unrolling the
	 * inner loop */
	if (encrypt)
	{
		for (i=0; i<32; i+=8)
		{
			D_ENCRYPT(l,r,i+0); /*  1 */
			D_ENCRYPT(r,l,i+2); /*  2 */
			D_ENCRYPT(l,r,i+4); /*  3 */
			D_ENCRYPT(r,l,i+6); /*  4 */
		}
	}
	else
	{
		for (i=30; i>0; i-=8)
		{
			D_ENCRYPT(l,r,i-0); /* 16 */
			D_ENCRYPT(r,l,i-2); /* 15 */
			D_ENCRYPT(l,r,i-4); /* 14 */
			D_ENCRYPT(r,l,i-6); /* 13 */
		}
	}
	l=(l>>1)|(l<<31);
	r=(r>>1)|(r<<31);
	/* clear the top bits on machines with 8byte longs */
	l&=0xffffffffL;
	r&=0xffffffffL;

	data[0]=l;
	data[1]=r;
	l=r=t=u=0;
}

void des_encrypt3(DES_LONG *data, des_key_schedule ks1, des_key_schedule ks2,
	     des_key_schedule ks3)
{
	register DES_LONG l,r;

	l=data[0];
	r=data[1];
	IP(l,r);
	data[0]=l;
	data[1]=r;
	des_encrypt2((DES_LONG *)data,ks1,DES_ENCRYPT);
	des_encrypt2((DES_LONG *)data,ks2,DES_DECRYPT);
	des_encrypt2((DES_LONG *)data,ks3,DES_ENCRYPT);
	l=data[0];
	r=data[1];
	FP(r,l);
	data[0]=l;
	data[1]=r;
}

void des_decrypt3(DES_LONG *data, des_key_schedule ks1, des_key_schedule ks2,
	     des_key_schedule ks3)
{
	register DES_LONG l,r;

	l=data[0];
	r=data[1];
	IP(l,r);
	data[0]=l;
	data[1]=r;
	des_encrypt2((DES_LONG *)data,ks3,DES_DECRYPT);
	des_encrypt2((DES_LONG *)data,ks2,DES_ENCRYPT);
	des_encrypt2((DES_LONG *)data,ks1,DES_DECRYPT);
	l=data[0];
	r=data[1];
	FP(r,l);
	data[0]=l;
	data[1]=r;
}

/* CBC en/de-crypt, with vector update for continuous data processing */
void des_cbc_encrypt3(const unsigned char *input, unsigned char *output,
	     long length, des_key_schedule ks1, des_key_schedule ks2,
	     des_key_schedule ks3, des_cblock *ivec, int enc)
{
	register DES_LONG tin0,tin1;
	register DES_LONG tout0,tout1,xor0,xor1;
	register const unsigned char *in;
	unsigned char *out;
	register long l=length;
	DES_LONG tin[2];
	unsigned char *iv;

	in=input;
	out=output;
	iv = &(*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;
			tin1^=tout1;

			tin[0]=tin0;
			tin[1]=tin1;
			des_encrypt3((DES_LONG *)tin,ks1,ks2,ks3);
			tout0=tin[0];
			tout1=tin[1];

			l2c(tout0,out);
			l2c(tout1,out);
		}
		if (l != -8)
		{
			c2ln(in,tin0,tin1,l+8);
			tin0^=tout0;
			tin1^=tout1;

			tin[0]=tin0;
			tin[1]=tin1;
			des_encrypt3((DES_LONG *)tin,ks1,ks2,ks3);
			tout0=tin[0];
			tout1=tin[1];

			l2c(tout0,out);
			l2c(tout1,out);
		}
		iv = &(*ivec)[0];
		l2c(tout0,iv);
		l2c(tout1,iv);
	}
	else
	{
		register DES_LONG t0,t1;

		c2l(iv,xor0);
		c2l(iv,xor1);
		for (l-=8; l>=0; l-=8)
		{
			c2l(in,tin0);
			c2l(in,tin1);

			t0=tin0;
			t1=tin1;

			tin[0]=tin0;
			tin[1]=tin1;
			des_decrypt3((DES_LONG *)tin,ks1,ks2,ks3);
			tout0=tin[0];
			tout1=tin[1];

			tout0^=xor0;
			tout1^=xor1;
			l2c(tout0,out);
			l2c(tout1,out);
			xor0=t0;
			xor1=t1;
		}
		if (l != -8)
		{
			c2l(in,tin0);
			c2l(in,tin1);
			
			t0=tin0;
			t1=tin1;

			tin[0]=tin0;
			tin[1]=tin1;
			des_decrypt3((DES_LONG *)tin,ks1,ks2,ks3);
			tout0=tin[0];
			tout1=tin[1];
		
			tout0^=xor0;
			tout1^=xor1;
			l2cn(tout0,tout1,out,l+8);
			xor0=t0;
			xor1=t1;
		}

		iv = &(*ivec)[0];
		l2c(xor0,iv);
		l2c(xor1,iv);
	}
	tin0=tin1=tout0=tout1=xor0=xor1=0;
	tin[0]=tin[1]=0;
}

/* ECB en/de-crypt, without vector update */
void des_ecb_encrypt3(des_cblock *input, des_cblock *output,
	     des_key_schedule ks1, des_key_schedule ks2, des_key_schedule ks3,
	     int enc)
{
	register DES_LONG l0,l1;
	DES_LONG ll[2];
	const unsigned char *in = &(*input)[0];
	unsigned char *out = &(*output)[0];

	c2l(in,l0);
	c2l(in,l1);
	ll[0]=l0;
	ll[1]=l1;
	if (enc)
		des_encrypt3(ll,ks1,ks2,ks3);
	else
		des_decrypt3(ll,ks1,ks2,ks3);
	l0=ll[0];
	l1=ll[1];
	l2c(l0,out);
	l2c(l1,out);
}