📄 des.c
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#include<stdio.h>
#include<string.h>
void Change2to16(char x[],int y[])// 将y[]中的64个2进制字符，改成16进制的字符串放到x[16]中
{
int a,c,d,e,f;
int xx;
for(a=0;a<16;a++)
{
c=y[a*4];
d=y[a*4+1];
e=y[a*4+2];
f=y[a*4+3];
xx=c*8+d*4+e*2+f;
switch(xx)
{
case 0: x[a]='0';break;
case 1: x[a]='1';break;
case 2: x[a]='2';break;
case 3: x[a]='3';break;
case 4: x[a]='4';break;
case 5: x[a]='5';break;
case 6: x[a]='6';break;
case 7: x[a]='7';break;
case 8: x[a]='8';break;
case 9: x[a]='9';break;
case 10: x[a]='A';break;
case 11: x[a]='B';break;
case 12: x[a]='C';break;
case 13: x[a]='D';break;
case 14: x[a]='E';break;
case 15: x[a]='F';break;
}
}
x[16]=0;
}
int Change16to2(int x[],char y[])//将y[]中的16个16进制字符，改成2进制放到x[64]中,正确返回1，错误返回0
{
int b=0;
int len;
int a;
char xxx;
len=strlen(y);
if(len!=16)
return 0;
for(a=0;a<16;a++)
{
xxx=y[a];
switch(xxx)
{
case '0': x[b++]=0;x[b++]=0;x[b++]=0;x[b++]=0;break;
case '1': x[b++]=0;x[b++]=0;x[b++]=0;x[b++]=1;break;
case '2': x[b++]=0;x[b++]=0;x[b++]=1;x[b++]=0;break;
case '3': x[b++]=0;x[b++]=0;x[b++]=1;x[b++]=1;break;
case '4': x[b++]=0;x[b++]=1;x[b++]=0;x[b++]=0;break;
case '5': x[b++]=0;x[b++]=1;x[b++]=0;x[b++]=1;break;
case '6': x[b++]=0;x[b++]=1;x[b++]=1;x[b++]=0;break;
case '7': x[b++]=0;x[b++]=1;x[b++]=1;x[b++]=1;break;
case '8': x[b++]=1;x[b++]=0;x[b++]=0;x[b++]=0;break;
case '9': x[b++]=1;x[b++]=0;x[b++]=0;x[b++]=1;break;
case 'A': x[b++]=1;x[b++]=0;x[b++]=1;x[b++]=0;break;
case 'B': x[b++]=1;x[b++]=0;x[b++]=1;x[b++]=1;break;
case 'C': x[b++]=1;x[b++]=1;x[b++]=0;x[b++]=0;break;
case 'D': x[b++]=1;x[b++]=1;x[b++]=0;x[b++]=1;break;
case 'E': x[b++]=1;x[b++]=1;x[b++]=1;x[b++]=0;break;
case 'F': x[b++]=1;x[b++]=1;x[b++]=1;x[b++]=1;break;
default: return 0;
}
}
return 1;
}
int ChangeWordto2(int x[],char y[])//将y[]中的8个字符，改成64个8进制数放到x[]中,正确返回1，错误返回0
{
int a,b,c,d;
int len;
len=strlen(y);
if(len!=8)
return 0;
for(a=0;a<8;a++)
{
c=y[a];
if((c<128)&&(c>=-127))
{
if(c<0)
c=c+256;
d=128;
for(b=0;b<8;b++)
{
x[a*8+b]=c/d;
c=c%d;
d=d/2;
}
}
else
return 0;
}
return 1;
}
int Pc2Table[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
};
int RipTable[64] =
{
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
};
int SBoxTable[8][64] =
{
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
};
void ZhiHuan(int x[],int y[])// 将y[32]数组中的数扩展置换到x[48]
{
int a;
x[0]=y[31];
x[1]=y[0];
x[2]=y[1];
x[3]=y[2];
x[4]=y[3];
x[5]=y[4];
for(a=1;a<7;a++)
{
x[a*6]=y[a*4-1];
x[a*6+1]=y[a*4];
x[a*6+2]=y[a*4+1];
x[a*6+3]=y[a*4+2];
x[a*6+4]=y[a*4+3];
x[a*6+5]=y[a*4+4];
}
x[42]=y[27];
x[43]=y[28];
x[44]=y[29];
x[45]=y[30];
x[46]=y[31];
x[47]=y[0];
}
void Xor(int x[],int y[],int n)//将x[n]同y[n]异或然后放到x[n]中
{
int a;
for(a=0;a<n;a++)
{
x[a]=(x[a]+y[a])%2;
}
}
void Swap(int x[],int y[])//将x[32]和y[32]数组数据交换
{
int temp[32];
int a;
for(a=0;a<32;a++)
{
temp[a]=x[a];
x[a]=y[a];
y[a]=temp[a];
}
}
void SBox(int x[],int y[])//将输入的y[48]经过S盒替换为x[32]
{
int temp;//存放十进制数
int a,c;
int b=0;
for(a=0;a<8;a++)
{//将SBox中由a0 a5 a1 a2 a3 a4 这个位置的数放入temp
c=y[a*6]*32+y[a*6+5]*16+y[a*6+1]*8+y[a*6+2]*4+y[a*6+3]*2+y[a*6+4];
temp=SBoxTable[a][c];
switch(temp)
{
case 0: x[b++]=0;x[b++]=0;x[b++]=0;x[b++]=0;break;
case 1: x[b++]=0;x[b++]=0;x[b++]=0;x[b++]=1;break;
case 2: x[b++]=0;x[b++]=0;x[b++]=1;x[b++]=0;break;
case 3: x[b++]=0;x[b++]=0;x[b++]=1;x[b++]=1;break;
case 4: x[b++]=0;x[b++]=1;x[b++]=0;x[b++]=0;break;
case 5: x[b++]=0;x[b++]=1;x[b++]=0;x[b++]=1;break;
case 6: x[b++]=0;x[b++]=1;x[b++]=1;x[b++]=0;break;
case 7: x[b++]=0;x[b++]=1;x[b++]=1;x[b++]=1;break;
case 8: x[b++]=1;x[b++]=0;x[b++]=0;x[b++]=0;break;
case 9: x[b++]=1;x[b++]=0;x[b++]=0;x[b++]=1;break;
case 10: x[b++]=1;x[b++]=0;x[b++]=1;x[b++]=0;break;
case 11: x[b++]=1;x[b++]=0;x[b++]=1;x[b++]=1;break;
case 12: x[b++]=1;x[b++]=1;x[b++]=0;x[b++]=0;break;
case 13: x[b++]=1;x[b++]=1;x[b++]=0;x[b++]=1;break;
case 14: x[b++]=1;x[b++]=1;x[b++]=1;x[b++]=0;break;
case 15: x[b++]=1;x[b++]=1;x[b++]=1;x[b++]=1;break;
}
}
}
void Rs(int x[],int n)//将x[28]右移n位
{
int a;
if (n==1)
{
int rstemp=x[27];
for(a =27;a>0;a--)
{
x[a]=x[a-1];
}
x[0]=rstemp;
}
else
{
int rstemp1=x[26];
int rstemp2=x[27];
for(a =27;a>1;a--)
{
x[a]=x[a-2];
}
x[0]=rstemp1;
x[1]=rstemp2;
}
}
void Rip(int x[],int y[])// 将y数组中的数逆ip换位到x数组
{
int a,b;
for(a=0;a<64;a++)
{
b=RipTable[a]-1;
x[a]=y[b];
}
}
void Pc2(int x[],int y[])//将y[56]经过Pc2盒置换为x[48]
{
int a,b;
for(a=0;a<48;a++)
{
b=Pc2Table[a]-1;
x[a]=y[b];
}
}
int Pc1Table[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, 23, 15,
7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29,
21, 13, 5, 28, 20, 12, 4
};
void Pc1(int x[],int y[])//将y[64]经过Pc1盒置换为x[56]
{
int a,b;
for(a=0;a<56;a++)
{
b=Pc1Table[a]-1;
x[a]=y[b];
}
}
int PBoxTable[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
};
void PBox(int x[],int y[])//将y[32]经过P盒替换为x[32]
{
int a,b;
for(a=0;a<32;a++)
{
b=PBoxTable[a]-1;
x[a]=y[b];
}
}
void Ls(int x[],int n)// 将x[28]左移n位
{
int a;
if (n==1)
{
int lstemp=x[0];
for(a =0;a<27;a++)
{
x[a]=x[a+1];
}
x[27]=lstemp;
}
else
{
int lstemp1=x[0];
int lstemp2=x[1];
for(a =0;a<26;a++)
{
x[a]=x[a+2];
}
x[26]=lstemp1;
x[27]=lstemp2;
}
}
void Change2toWord(char x[],int y[])// 将y[]中的64个2进制字符，改成8位字符串放到x[16]中
{
int a,b,c,sum;
for(a=0;a<8;a++)
{
sum=0;
c=128;
for(b=0;b<8;b++)
{
sum=sum+y[a*8+b]*c;
c=c/2;
}
x[a]=sum;
}
x[8]=0;
}
int IpTable[64] =
{
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
};
void Ip(int x[],int y[])//将y数组中的数ip换位到x数组
{
int a,b;
for(a=0;a<64;a++)
{
b=IpTable[a]-1;
x[a]=y[b];
}
}
int main()
{
char ming_input[100];
char key_input[100];
int ming[65];//2进制的明文
int mi[65];
int key_beforeip[64];
int k[48];//子密钥
int C[28],D[28];
int ming_afterip[64];
int key[56];
int temp1[48];//扩展置换后的R
int temp2[32];//S盒替换后的R
int temp3[32];//P盒替换后的R
char temp5[100];
int L[32],R[32];
int a,aa;//用于计数
int sign;
printf("Input Key:\n");
gets(key_input);
printf("Input PlainText:\n");
gets(ming_input);
printf("CipherText:\n");
sign=Change16to2(key_beforeip,key_input);
if(!sign)
{
printf("input wrong!\n");
return 0;
}
sign=ChangeWordto2(ming,ming_input);
if(!sign)
{
printf("input wrong!\n");
return 0;
}
Ip(ming_afterip,ming);//ip换位 ming->ming_afterip
for(a=0;a<32;a++)//将ming_afterip分成L和R
{
L[a]=ming_afterip[a];
R[a]=ming_afterip[a+32];
}
Pc1(key,key_beforeip);//Pc1置换 key_beforeip->key
for(a=0;a<28;a++)//将key_afterpc1分成C和D
{
C[a]=key[a];
D[a]=key[a+28];
}
for(a=1;a<=16;a++)//循环16次
{
ZhiHuan(temp1,R);//扩展置换 R->temp1
if(a==1||a==2||a==9||a==16)//开始生成子密钥
{
Ls(C,1);
Ls(D,1);//左移1位
}
else
{
Ls(C,2);
Ls(D,2);//左移2位
}
for(aa=0;aa<28;aa++)//将C和D重新合成key
{
key[aa]=C[aa];
key[aa+28]=D[aa];
}
Pc2(k,key);//Pc2置换 key->k
Xor(temp1,k,48);//异或 temp1和子密钥k
SBox(temp2,temp1);//S盒替换 temp1->temp2///奇怪，这里temp4变了？
PBox(temp3,temp2);//P盒替换 temp2->temp3
Xor(L,temp3,32);//异或 L和temp3
Swap(R,L);
}
for(a=0;a<32;a++)//将R和L重新合成ming，最后一次没有交换,所以R在前面
{
ming[a]=R[a];
ming[a+32]=L[a];
}
Rip(mi,ming); //逆Ip ming->mi
Change2to16(temp5,mi);
puts(temp5);
////////////////////////////加密完成////////////////////////////
printf("Decryption:\n");
Change16to2(ming,temp5);
Ip(ming_afterip,ming);//ip换位 ming->ming_afterip
for(a=0;a<32;a++)//将ming_afterip分成L和R
{
L[a]=ming_afterip[a];
R[a]=ming_afterip[a+32];
}
Pc1(key,key_beforeip);//Pc1置换 key_beforeip->key
for(a=0;a<28;a++)//将key_afterpc1分成C和D
{
C[a]=key[a];
D[a]=key[a+28];
}
for(a=1;a<=16;a++)//循环16次
{
ZhiHuan(temp1,R);//扩展置换 R->temp1
if(a==1)
{}
else if(a==2||a==9||a==16)//开始生成子密钥
{
Rs(C,1);
Rs(D,1);//右移1位
}
else
{
Rs(C,2);
Rs(D,2);//右移2位
}
for(aa=0;aa<28;aa++)//将C和D重新合成key
{
key[aa]=C[aa];
key[aa+28]=D[aa];
}
Pc2(k,key);//Pc2置换 key->k
Xor(temp1,k,48);//异或 temp1和子密钥k
SBox(temp2,temp1);//S盒替换 temp1->temp2///奇怪，这里temp4变了？
PBox(temp3,temp2);//P盒替换 temp2->temp3
Xor(L,temp3,32);//异或 L和temp3
Swap(R,L);
}
for(a=0;a<32;a++)//将R和L重新合成ming，最后一次没有交换,所以R在前面
{
ming[a]=R[a];
ming[a+32]=L[a];
}
Rip(mi,ming); //逆Ip ming->mi
Change2toWord(temp5,mi);
puts(temp5);
return 1;
}⌨️ 快捷键说明
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