📄 des.cpp
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#include<stdio.h>
#include<string.h>
void Ip(int y[64],int x[64])
{
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
};
for(int i=0;i<64;i++)
y[i]=x[IpTable[i]-1];
}
void Pc1(int y[56],int x[64])
{
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
};
for(int i=0;i<56;i++)
y[i]=x[Pc1Table[i]-1];
}
void Expand(int y[48],int x[32])
{
int Etable[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
};
for(int i=0;i<48;i++)
y[i]=x[Etable[i]-1];
}
void Ls(int x[28],int n)// 将x[28]左移n位
{
if (n==1)
{
int lstemp=x[0];
for(int a =0;a<27;a++)
{
x[a]=x[a+1];
}
x[27]=lstemp;
}
else
{
int lstemp1=x[0];
int lstemp2=x[1];
for(int a =0;a<26;a++)
{
x[a]=x[a+2];
}
x[26]=lstemp1;
x[27]=lstemp2;
}
}
void Rs(int x[],int n)//将x[28]右移n位
{
if (n==1)
{
int rstemp=x[27];
for(int a =27;a>0;a--)
{
x[a]=x[a-1];
}
x[0]=rstemp;
}
else
{
int rstemp1=x[26];
int rstemp2=x[27];
for(int a =27;a>1;a--)
{
x[a]=x[a-2];
}
x[0]=rstemp1;
x[1]=rstemp2;
}
}
void Pc2(int y[48],int x[56])
{
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
};
for(int i=0;i<48;i++)
y[i]=x[Pc2Table[i]-1];
}
void Xor(int x[],int y[],int n)
{
for(int a =0;a<n;a++)
{
x[a]=(x[a]+y[a])%2;
}
}
void SBox(int x[32],int y[48] )
{
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
};
int temp;//存放十进制数
int c;
int b=0;
for(int 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 PBox(int x[32],int y[32])
{
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
};
for(int i=0;i<32;i++)
x[i]=y[PBoxTable[i]-1];
}
void Swap(int x[32],int y[32])//将x[32]和y[32]数组数据交换
{
int temp[32];
for(int a=0;a<32;a++)
{
temp[a]=x[a];
x[a]=y[a];
y[a]=temp[a];
}
}
void Rip(int x[64],int y[64])
{
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
};
for(int i=0;i<64;i++)
x[i]=y[RipTable[i]-1];
}
void Change16To2(int x[64],char y[16])// 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;
char xxx;
for(int 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;
}
}
}
void Change2To16(char x[16],int y[64])// 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 c,d,e,f;
int xx;
for(int 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;
}
}
}
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;
}
}
int ChangeWordTo2(int x[64],char y[8])//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;
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;
}
c=y[a];
if(c==0)
return 1;
else
return 0;
}
void Encryption(char plaintext[8],char keytext[16],char ciphertext[16])
{
int ming[64], ming_afterip[64],mi[64];
int key[56],key_beforeip[64];
int L[32],R[32];
int k[48];
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
int C[28],D[28];
int a;
ChangeWordTo2(ming,plaintext);
Change16To2(key_beforeip,keytext);
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
{
Expand(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(int 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
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,所以要把R在前面
{
ming[a]=R[a];
ming[a+32]=L[a];
}
Rip(mi,ming); //逆Ip ming->mi
Change2To16(ciphertext,mi);
}
void Decryption(char ciphertext[16],char keytext[16],char decrytext[8])
{
int mi[64], mi_afterip[64];
int key[56],key_beforeip[64];
int cipher[64];
int k[48];
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
int C[28],D[28];
int L[32],R[32];
int a;
ChangeWordTo2(mi,ciphertext);
Change16To2(key_beforeip,keytext);
Ip(mi_afterip,mi);//ip换位 mi->mi_afterip
for(a=0;a<32;a++)//将mi_afterip分成L和R
{
L[a]=mi_afterip[a];
R[a]=mi_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
{
Expand(temp1,R);//扩展置换 R->temp1
if(a==1||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(int 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/
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mi，最后一次没有交换,所以R在前面
{
mi[a]=R[a];
mi[a+32]=L[a];
}
Rip(cipher,mi); //逆Ip mi->cipher
Change2ToWord(decrytext,cipher);
}
void main()
{
char plaintext[8];
char key[16];
char ciphertext[16];
char decryptext[8];
printf("input key:\n");
for(int j=0;j<16;j++)
scanf("%c",&key[j]);
printf("input PlainText:\n");
for(j=0;j<8;j++)
scanf("%c",&plaintext[j]);
Encryption(plaintext,key,ciphertext); //解密
printf("CipherText:\n");
for(j=0;j<16;j++)
printf("%c",ciphertext[j]);
printf("\n");
Decryption(ciphertext,key,decryptext); //加密
printf("Decryption:\n");
for(j=0;j<8;j++)
printf("%c",decryptext[j]);
printf("\n");
}⌨️ 快捷键说明
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