des3.cpp

三重DES增加了密钥长度

#include "des3.h"


int des3_ecb_encrypt(const unsigned char *pt, unsigned char *ct,const unsigned char *key,int keylen)
{
    _ARGCHK(pt != NULL);
    _ARGCHK(ct != NULL);
    _ARGCHK(key != NULL);

	if(keylen != 16)
	{
		printf("Error in 3DES key length");
		return 1;
	}

	unsigned char key1[8],key2[8];
	symmetric_key skey1,skey2;
	int num_rounds = 0;

	int i;
	for(i=0;i<7;i++)
	{
		key1[i] = key[i];
		key2[i] = key[i+8];
	}
	
	if(des_setup(key1, 8, num_rounds, &skey1))
	{
		printf("Set up error!\n");
		return 1;
	}
	if(des_setup(key2, 8, num_rounds, &skey2))
	{
		printf("Set up error!\n");
		return 1;
	}

	int length = 0 ;
	while(pt[length]!='\0')
		length++;

	unsigned char * pp;
	pp = new unsigned char(length);

	des_ecb_encrypt(pt,ct,&skey1);
	des_ecb_decrypt(ct,pp,&skey2);
	des_ecb_encrypt(pp,ct,&skey1);
	return 0;
}

int des3_ecb_decrypt(const unsigned char *pt, unsigned char *ct,const unsigned char *key,int keylen)
{
    _ARGCHK(pt != NULL);
    _ARGCHK(ct != NULL);
    _ARGCHK(key != NULL);

	if(keylen != 16)
	{
		printf("Error in 3DES key length");
		return 1;
	}

	unsigned char key1[8],key2[8];
	symmetric_key skey1,skey2;
	int num_rounds = 0;

	int i;
	for(i=0;i<7;i++)
	{
		key1[i] = key[i];
		key2[i] = key[i+8];
	}
	
	if(des_setup(key1, 8, num_rounds, &skey1))
	{
		printf("Set up error!\n");
		return 1;
	}
	if(des_setup(key2, 8, num_rounds, &skey2))
	{
		printf("Set up error!\n");
		return 1;
	}

	int length = 0 ;
	while(pt[length]!='\0')
		length++;

	unsigned char * pp;
	pp = new unsigned char(length);
	
	des_ecb_decrypt(pt,ct,&skey1);
	des_ecb_encrypt(ct,pp,&skey2);
	des_ecb_decrypt(pp,ct,&skey1);	

	return 0;
}
/*
void main()
{
	unsigned char pt[8]={"0123456"};
	unsigned char ct[8];
	unsigned char ppt[8];
	unsigned char key[16]="012345678901234";

	pt[7]=ct[7]=ppt[7]='\0';
	key[7]=key[15]='\0';
	 
	des3_ecb_encrypt(pt,ct,key,16);
	des3_ecb_decrypt(ct,ppt,key,16);
}
*/