des是对称加密吗

发布时间: 2022-05-02 07:35:48

Ⅰ DES加密和解密的对称性

#include <iostream>
#include <fstream>
using namespace std;
const static char ip[] = { //IP置换
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
};
const static char fp[] = { //zuizhonghuan
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
};
const static char sbox[8][64] = { //s_box
/* S1 */
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,

/* S2 */
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,

/* S3 */
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,

/* S4 */
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,

/* S5 */
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,

/* S6 */
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,

/* S7 */
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,

/* S8 */
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
};
const static char rar[] = { //ya suo huan
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
};
const static char ei[] = { //kuo zhan huan
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
};
const static char Pzh[]={ //P置换
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
};
const static char Keyrar[]={
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
};
bool key[16][48]={0},/*rekey[16][48],*/
char key_in[8];
void ByteToBit(bool *Out,char *In,int bits) //字节到位的转换
{
int i;
for(i=0;i<bits;i++)
Out[i]=(In[i/8]>>(i%8))&1;
}
void BitToByte(char *Out,bool *In,int bits) //位到字节转换
{
for(int i=0;i<bits/8;i++)
Out[i]=0;
for(i=0;i<bits;i++)
Out[i/8]|=In[i]<<(i%8); //"|="组合了位操作符和赋值操作符的功能
}
void Xor(bool *InA,const bool *InB,int len) //按位异或
{
for(int i=0;i<len;i++)
InA[i]^=InB[i];
}
void keyfc(char *In) //获取密钥函数
{
int i,j=0,mov,k;
bool key0[56],temp,keyin[64];
ByteToBit(keyin,In,64); //字节到位的转换
for(i=0;i<56;i++) //密钥压缩为56位
key0[i]=keyin[Keyrar[i]-1];
for(i=0;i<16;i++) //16轮密钥产生
{
if(i==0||i==1||i==8||i==15)
mov=1;
else
mov=2;
for(k=0;k<mov;k++) //分左右两块循环左移
{
// for(int m=0;m<8;m++)
// {
// temp=key0[m*7];
// for(j=m*7;j<m*7+7;j++)
// key0[j]=key0[j+1];
// key0[m*7+6]=temp;
// }
temp=key0[0];
for(int m=0;m<27;m++)
key0[m]=key0[m+1];
key0[27]=temp;
temp=key0[28];
for(m=28;m<55;m++)
key0[m]=key0[m+1];
key0[55]=temp;
}

for(j=0;j<48;j++) //压缩置换并储存
key[i][j]=key0[rar[j]-1];
}
}

void DES(char Out[8],char In[8],bool MS)//加密核心程序,ms=0时加密，反之解密
{
bool MW[64],tmp[32],PMW[64]; //注意指针
bool kzmw[48],keytem[48],ss[32];
int hang,lie;
ByteToBit(PMW,In,64);
for(int j=0;j<64;j++)
{
MW[j]=PMW[ip[j]-1]; //初始置换
}
bool *Li=&MW[0],*Ri=&MW[32];
for(int i=0;i<48;i++) //右明文扩展置换
kzmw[i]=Ri[ei[i]-1]; //注意指针

if(MS==0) //DES加密过程
{
for(int lun=0;lun<16;lun++)
{
for(i=0;i<32;i++)
ss[i]=Ri[i];
for(i=0;i<48;i++) //右明文扩展置换
kzmw[i]=Ri[ei[i]-1]; //注意指针
for(i=0;i<48;i++)
keytem[i]=key[lun][i]; //轮密钥
Xor(kzmw,keytem,48);
/*S盒置换*/
for(i=0;i<8;i++)
{
hang=kzmw[i*6]*2+kzmw[i*6+5];
lie =kzmw[i*6+1]*8+kzmw[i*6+2]*4+kzmw[i*6+3]*2+kzmw[i*6+4];
tmp[i*4+3]=sbox[i][(hang+1)*16+lie]%2;
tmp[i*4+2]=(sbox[i][(hang+1)*16+lie]/2)%2;
tmp[i*4+1]=(sbox[i][(hang+1)*16+lie]/4)%2;
tmp[i*4]=(sbox[i][(hang+1)*16+lie]/8)%2;
}

for(int i=0;i<32;i++) //P置换
Ri[i]=tmp[Pzh[i]-1];
Xor(Ri,Li,32); //异或
for(i=0;i<32;i++) //交换左右明文
{
Li[i]=ss[i];
}
}
for(i=0;i<32;i++)
{
tmp[i]=Li[i];
Li[i]=Ri[i];
Ri[i]=tmp[i];
}
for(i=0;i<64;i++)
PMW[i]=MW[fp[i]-1];
BitToByte(Out,PMW,64); //位到字节的转换
}
else //DES解密过程
{

for(int lun=15;lun>=0;lun--)
{
for(i=0;i<32;i++)
ss[i]=Ri[i];
for(int i=0;i<48;i++) //右明文扩展置换
kzmw[i]=Ri[ei[i]-1]; //注意指针
for(i=0;i<48;i++)
keytem[i]=key[lun][i]; //轮密钥
Xor(kzmw,keytem,48);
/*S盒置换*/
for(i=0;i<8;i++)
{
hang=kzmw[i*6]*2+kzmw[i*6+5];
lie =kzmw[i*6+1]*8+kzmw[i*6+2]*4+kzmw[i*6+3]*2+kzmw[i*6+4];
tmp[i*4+3]=sbox[i][(hang+1)*16+lie]%2;
tmp[i*4+2]=(sbox[i][(hang+1)*16+lie]/2)%2;
tmp[i*4+1]=(sbox[i][(hang+1)*16+lie]/4)%2;
tmp[i*4]=(sbox[i][(hang+1)*16+lie]/8)%2;
}

for(i=0;i<32;i++) //P置换
Ri[i]=tmp[Pzh[i]-1];
Xor(Ri,Li,32); //异或
for(i=0;i<32;i++) //交换左右明文
{
Li[i]=ss[i];
}

}
for(i=0;i<32;i++)
{
tmp[i]=Li[i];
Li[i]=Ri[i];
Ri[i]=tmp[i];
}
for(i=0;i<64;i++)
PMW[i]=MW[fp[i]-1];
BitToByte(Out,PMW,64); //位到字节的转换
}
}
void main()
{
char Ki[8],jm[8],final[8];
int i0;
cout<<"请输入密钥（8字节）："<<endl;
for(i0=0;i0<8;i0++)
cin>>Ki[i0];
// if(i0<8)
// for(i0=0;i0<8;i0++)
// cin//[i0];
keyfc(Ki);
cout<<"请输入明文："<<endl;
for(i0=0;i0<8;i0++)
cin>>jm[i0];
DES(final,jm,0); //加密
for(i0=0;i0<8;i0++)
cout<<final[i0];
cout<<endl;
DES(jm,final,1); //解密
for(i0=0;i0<8;i0++)
cout<<jm[i0];
cout<<endl;
}
这个事用VC实现
给你算法你自己看

Ⅱ des是对称加密算法还是非对称加密算法加密密钥是多少位

对称加密的加密和解密密钥都是一样的。而非对称加密的加密和解密密钥是不一样的。它们的算法也是不同的。 l 对称加密算法对称加密算法是应用较早的加密算法，技术成熟。在对称加密算法中，数据发信方将明文（原始数据）和加密密钥一起经过特殊...

Ⅲ des算法是什么

DES算法为密码体制中的对称密码体制，又被称为美国数据加密标准，是1972年美国IBM公司研制的对称密码体制加密算法。

des是对称加密吗

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