}
else
return0;
}
}
测试:
密钥:
4,明文:
abcdefg
实验结果:
实验二DES加密解密
加密原理:
DES使用一个56位的密钥以及附加的8位奇偶校验位,产生最大64位的分组大小。
这是一个迭代的分组密码,使用称为Feistel的技术,其中将加密的文本块分成两半。
使用子密钥对其中一半应用循环功能,然后将输出与另一半进行“异或”运算;接着交换这两半,这一过程会继续下去,但最后一个循环不交换。
DES使用16个循环,使用异或,置换,代换,移位操作四种基本运算。
源代码:
#include
#include
#include"des_encode.h"
intkey[16][48];
charstr[8];
voidmain()
{
EncodeMain();
}
voidEncodeMain()
{
inti;
charkeychar[8];
intkey2[8];
intstrkey[8];
printf("请输入8个要加密的字符:
\n");
for(i=0;i<8;i++)
scanf("%c",&str[i]);
getchar();
for(i=0;i<8;i++)
strkey[i]=str[i];
printf("\n输入明文的十六进制为:
\n");
for(i=0;i<8;i++)
printf("%10x",strkey[i]);
printf("\n请输入密钥(8个字符):
\n");
for(i=0;i<8;i++)
scanf("%c",&keychar[i]);
for(i=0;i<8;i++)
key2[i]=keychar[i];
getchar();
Encode(strkey,key2);
printf("\n加密后十六进制密文是:
\n");
for(i=0;i<8;i++)
printf("%10x",strkey[i]);
printf("\n\n请输入解密密码\n");
for(i=0;i<8;i++)
scanf("%c",&keychar[i]);
for(i=0;i<8;i++)
key2[i]=keychar[i];
Decode(strkey,key2);
for(i=0;i<8;i++)
printf("%10x",strkey[i]);
for(i=0;i<8;i++)
str[i]=strkey[i];
printf("\n明文为:
\t");
for(i=0;i<8;i++)
printf("%c",str[i]);
printf("\n\n");
}
voidkeyBuild(int*keychar){
inti,j;
intmovebit[]={1,1,2,2,2,2,2,2,
1,2,2,2,2,2,2,1};
intmidkey2[56];
intmidkey[64];
StrtoBin(midkey,keychar);
for(i=0;i<56;i++)
midkey2[i]=midkey[PC1[i]-1];
for(i=0;i<16;i++)
keyCreate(midkey2,movebit[i],i);
}
voidStrtoBin(int*midkey,int*keychar){
inttrans[8],i,j,k,n;
n=0;
for(i=0;i<8;i++){
j=0;
while(keychar[i]!
=0){
trans[j]=keychar[i]%2;
keychar[i]=keychar[i]/2;
j++;
}
for(k=j;k<8;k++)trans[k]=0;
for(k=0;k<8;k++)
midkey[n++]=trans[7-k];
}
}
voidkeyCreate(int*midkey2,intmovebit,intn){
inti,temp[4];
temp[0]=midkey2[0];
temp[1]=midkey2[1];
temp[2]=midkey2[28];
temp[3]=midkey2[29];
if(movebit==2){
for(i=0;i<26;i++){
midkey2[i]=midkey2[i+2];
midkey2[i+28]=midkey2[i+30];
}
midkey2[26]=temp[0];midkey2[27]=temp[1];
midkey2[54]=temp[2];midkey2[55]=temp[3];}
else
{for(i=0;i<27;i++){
midkey2[i]=midkey2[i+1];
midkey2[i+28]=midkey2[i+29];
}
midkey2[27]=temp[0];midkey2[55]=temp[2];
}
for(i=0;i<48;i++)
key[n][i]=midkey2[PC2[i]-1];
}
voidEncodeData(int*lData,int*rData,int*str){
inti,j,temp[8],lint,rint;
intdata[64];
lint=0,rint=0;
for(i=0;i<4;i++){
j=0;
while(str[i]!
=0){
temp[j]=str[i]%2;
str[i]=str[i]/2;
j++;
}
while(j<8)temp[j++]=0;
for(j=0;j<8;j++)
lData[lint++]=temp[7-j];
j=0;
while(str[i+4]!
=0){
temp[j]=str[i+4]%2;
str[i+4]=str[i+4]/2;
j++;
}
while(j<8)temp[j++]=0;
for(j=0;j<8;j++)rData[rint++]=temp[7-j];
}
for(i=0;i<32;i++){
data[i]=lData[i];
data[i+32]=rData[i];
}
for(i=0;i<32;i++){
lData[i]=data[IP1[i]-1];
rData[i]=data[IP1[i+32]-1];
}
}
voidF(int*rData,int*key){
inti,rDataP[48];
Expand(rData,rDataP);
for(i=0;i<48;i++){
rDataP[i]=rDataP[i]^key[i];
}
ExchangeS(rDataP,rData);
ExchangeP(rData);
}
voidExpand(int*rData,int*rDataP){
inti;
for(i=0;i<48;i++)
rDataP[i]=rData[Ex[i]-1];
}
voidExchangeS(int*rDataP,int*rData){
inti,n,linex,liney;
linex=liney=0;
for(i=0;i<48;i+=6){
n=i/6;
linex=(rDataP[i]<<1)+rDataP[i+5];
liney=(rDataP[i+1]<<3)+(rDataP[i+2]<<2)+(rDataP[i+3]<<1)+rDataP[i+4];
FillBin(rData,n,s[n][linex][liney]);
}
}
voidExchangeP(int*rData){
inti,temp[32];
for(i=0;i<32;i++)
temp[i]=rData[i];
for(i=0;i<32;i++)
rData[i]=temp[P[i]-1];
}
voidFillBin(int*rData,intn,ints){
inttemp[4],i;
for(i=0;i<4;i++){
temp[i]=s%2;
s=s/2;
}
for(i=0;i<4;i++)
rData[n*4+i]=temp[3-i];
}
voidDecodeData(int*str,int*lData,int*rData){
inti;inta,b;intdata[64];
a=0,b=0;
for(i=0;i<32;i++){
data[i]=lData[i];
data[i+32]=rData[i];
}
for(i=0;i<32;i++){
lData[i]=data[IP2[i]-1];
rData[i]=data[IP2[i+32]-1];
}
for(i=0;i<32;i++){
a=(lData[i]&0x1)+(a<<1);
b=(rData[i]&0x1)+(b<<1);
if((i+1)%8==0){
str[i/8]=a;a=0;
str[i/8+4]=b;b=0;
}
}
}
voidEncode(int*str,int*keychar){
intlData[32],rData[32],temp[32],rDataP[48];
inti,j;
keyBuild(keychar);
EncodeData(lData,rData,str);
for(i=0;i<16;i++){
for(j=0;j<32;j++)
temp[j]=rData[j];
F(rData,key[i]);
for(j=0;j<32;j++){
rData[j]=rData[j]^lData[j];
}
for(j=0;j<32;j++)
lData[j]=temp[j];
}
DecodeData(str,rData,lData);
}
voidDecode(int*str,int*keychar){
intlData[32],rData[32],temp[32],rDataP[48];
inti,j;
keyBuild(keychar);
EncodeData(lData,rData,str);
for(i=0;i<16;i++){
for(j=0;j<32;j++)
temp[j]=rData[j];
F(rData,key[15-i]);
for(j=0;j<32;j++){
rData[j]=rData[j]^lData[j];
}
for(j=0;j<32;j++){
lData[j]=temp[j];
}
}
DecodeData(str,rData,lData);
}
des_encode.h
voidEncodeMain();
voidDecodeMain();
voidDecode(int*str,int*keychar);
voidEncode(int*str,int*keychar);
voidkeyBuild(int*keychar);
voidStrtoBin(int*midkey,int*keychar);
voidkeyCreate(int*midkey2,intmovebit,inti);
voidEncodeData(int*lData,int*rData,int*srt);
voidF(int*rData,int*key);
voidExpand(int*rData,int*rDataP);
voidExchangeS(int*rDataP,int*rData);
voidExchangeP(int*rData);
voidFillBin(int*rData,intn,ints);
voidDecodeData(int*str,int*lData,int*rData);
intIP1[]={58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4,
62,54,46,38,30,22,14,6,64,56,48,40,32,24,16,8,
57,49,41,33,25,17,9,1,59,51,43,35,27,19,11,3,
61,53,45,37,29,21,13,5,63,55,47,39,31,23,15,7,
};
intIP2[]={40,8,48,16,56,24,64,32,39,7,47,15,55,23,63,31,
38,6,46,14,54,22,62,30,37,5,45,13,53,21,61,29,
36,4,44,12,52,20,60,28,35,3,43,11,51,19,59,27,
34,2,42,10,50,18,58,26,33,1,41,9,49,17,57,25
};
ints[][4][16]={{
{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
{0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
{4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
{15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}
},
{
{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
{3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
{0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
{13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}
},
{
{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
{13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
{13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
{1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}
},
{
{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
{13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
{10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
{3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}
},
{
{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
{14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
{4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
{11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}
},
{
{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
{10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
{9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
{4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}
},
{
{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
{13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
{1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
{6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}
},
{
{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
{1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
{7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
{2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
}
};
intEx[48]={32,1,2,3,4,5,
4,5,6,7,8,9,
8,9,10,11,12,13,
12,13,14,15,16,17,
16,17,18,19,20,21,
20,21,22,23,24,25,
24,25,26,27,28,29,
28,29,30,31,32,1
};
intP[32]={16,7,20,21,
29,12,28,17,
1,15,23,26,
5,18,31,10,
2,8,24,14,
32,27,3,9,
19,13,30,6,
22,11,4,25
};
intPC1[56]={57,49,41,33,25,17,9,
1,58,50,42,34,26,18,
10,2,59,51,43,35,27,
19,11,3,60,52,44,36,
63,55,47,39,31,33,15,
7,62,54,46,38,30,22,
14,6,61,53,45,37,29,
21,13,5,28,20,12,4
};
intPC2[48]={14,17,11,24,1,5,
3,28,15,6,21,10,
23,19,12,4,26,8,
16,7,27,20,13,2,
41,52,31,37,47,55,
30,40,51,45,33,48,
44,49,39,56,34,53,
46,42,50,36,29,32
};
测