📄 des.cpp
字号:
#ifndef _DES_H_
#define _DES_H_
/* 说明：将56位的密钥加上奇偶位变为64位，该功能还未实现
* 加密解密只是能对64位的明文或密文进行，分块的功能还未实现
*/
#include <iostream>
using namespace std;
#define BIT bool
#define BYTE unsigned char
class Des
{
private:
BIT subKey[16][48]; // 16圈子密钥
static BYTE IpTable[64]; // 置换IP表
static BYTE IprTable[64]; // 逆置换IP-1表
static BYTE Etable[48]; // E 位选择表(拓展置换）
static BYTE Ptable[32]; // P换位表
static BYTE Pc1Table[56]; // pc1选位表
static BYTE Pc2Table[48]; // pc2选位表
static BYTE LoopTable[16]; // 左移位数表
static BYTE Sbox[8][4][16]; // S盒
public:
Des();
void Cipher(BYTE out[8], const BYTE in[8]); // 加密64位输入
void InvCipher(BYTE out[8], const BYTE in[8]); // 解密64位输入
void SetKey(const BYTE key[8]); // 设置密钥
static void Ffunc(BIT in[32], const BIT ki[48]); // f函数
static void Sfunc(BIT out[32], const BIT in[48]); // s盒代替
static void RotateL(BIT *in, int len, int loop); // 循环左移
static void Xor(BIT *ina, const BIT *inb, int len); // 异或
static void ByteToBit(BIT *out, const BYTE *in, int bits); // 字节组转换成位组
static void BitToByte(BYTE *out, const BIT *in, int bits); // 位组转换成字节组
static void Transform(BIT *out, BIT *in, const BYTE *table, int len); // 变换（凡涉及表格转换的均使用此函数）
private:
Des(const Des& des);
Des operator=(const Des& des);
};
#endif
Des::Des()
{
}
// 置换IP表
BYTE Des::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
};
// 逆置换IP-1表
BYTE Des::IprTable[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
};
// E 位选择表
BYTE Des::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
};
// P换位表
BYTE Des::Ptable[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
};
// pc1选位表
BYTE Des::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
};
// pc2选位表
BYTE Des::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
};
// 左移位数表
BYTE Des::LoopTable[16] = {
1, 1, 2, 2, 2, 2, 2, 2,
1, 2, 2, 2, 2, 2, 2, 1
};
// S盒
BYTE Des::Sbox[8][4][16] = {
//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
};
//生成16轮子密钥
void Des::SetKey(const BYTE key[8])
{
static BIT k[64],
*kl=&k[0],
*kr=&k[28];
ByteToBit(k, key, 64); //将输入的8字节转换为64位（在本程序中用一个字节长度储存一个位）
Transform(k, k, Pc1Table, 56); //置换选择P1，此时k数组中有56位
for(int i=0; i<16; i++)
{
RotateL(kl, 28, LoopTable[i]); //前28位进行循环左移
RotateL(kr, 28, LoopTable[i]); //后28位进行循环左移
Transform(subKey[i], k, Pc2Table, 48); //置换选择P2，此时k数组有48位
}
}
// f函数
void Des::Ffunc(BIT in[32], const BIT ki[48]) //明文为in数组，子密钥位ki数组
{
static BIT mr[48];
Transform(mr, in, Etable, 48); // 扩展置换，结果在mr数组中
Xor(mr, ki, 48); // mr与子密钥异或，结果在mr数组中
Sfunc(in, mr); // S盒替换
Transform(in, in, Ptable, 32); // P盒替换
}
// s盒代替
void Des::Sfunc(BIT out[32], const BIT in[48])
{
for(BYTE i=0, j, k; i<8; i++, in+=6, out+=4) //每次输入数组in移六位，输出数组out移四位，总共8轮
{
j = (in[0] << 1) + in[5]; // 第一位和第六位相加
k = (in[1] << 3) + (in[2] << 2) + (in[3] << 1) + in[4]; //中间四位相加
ByteToBit(out, &Sbox[i][j][k], 4); //根据i j k得到Sbox数组的元素，并将其转换为四位的bit存到out数组中
}
}
// 循环左移
void Des::RotateL(BIT *in, int len, int loop)
{
static BIT tmp[256];
memcpy(tmp, in, sizeof(BIT) * loop);
memcpy(in, in+loop, sizeof(BIT) * (len-loop));
memcpy(in+len-loop, tmp, sizeof(BIT) * loop);
}
// 异或
void Des::Xor(BIT *ina, const BIT *inb, int len)
{
for(int i=0; i<len; i++)
{
ina[i] ^= inb[i];
}
}
// 字节组转换成位组
void Des::ByteToBit(BIT *out, const BYTE *in, int bits)
{
for(int i=0; i<bits; i++)
{
out[i] = (in[i/8] >> (i%8)) & 1;
}
}
// 位组转换成字节组
void Des::BitToByte(BYTE *out, const BIT *in, int bits)
{
memset(out, 0, (bits+7) / 8);
for(int i=0; i<bits; i++)
{
out[i/8] |= in[i] << (i%8);
}
}
// 变换
void Des::Transform(BIT *out, BIT *in, const BYTE *table, int len)
{
static BIT tmp[256];
for(int i=0; i<len; i++)
{
tmp[i] = in[table[i]-1];
}
memcpy(out, tmp, sizeof(BIT) * len);
}
// 加密64位输入
void Des::Cipher(BYTE out[8], const BYTE in[8])
{
static BIT m[64],
tmp[32],
*li = &m[0],
*ri=&m[32];
ByteToBit(m, in, 64);
Transform(m, m, IpTable, 64);
for(int i=0; i<16; i++)
{
memcpy(tmp, ri, 32);
Ffunc(ri, subKey[i]);
Xor(ri, li, 32);
memcpy(li, tmp, 32);
}
memcpy(tmp, ri, 32);
memcpy(ri,li,32);
memcpy(li, tmp, 32);
Transform(m, m, IprTable, 64);
BitToByte(out, m, 64);
}
// 解密64位输入
void Des::InvCipher(BYTE out[8], const BYTE in[8])
{
static BIT m[64],
tmp[32],
*li = &m[0],
*ri=&m[32];
ByteToBit(m, in, 64);
Transform(m, m, IpTable, 64);
memcpy(tmp, ri, 32);
memcpy(ri,li,32);
memcpy(li, tmp, 32);
for(int i=15; i>=0; i--)
{
memcpy(tmp, li, 32);
Ffunc(li,subKey[i]);
Xor(li, ri, 32);
memcpy(ri, tmp, 32);
}
Transform(m, m, IprTable, 64);
BitToByte(out, m, 64);
}
//////////////////////// TEST ////////////////////////////
#include <iostream>
using namespace std;
int main()
{
BYTE key[16],
zero = 0, // something relate to buffer overflow
str[100],output[100];
int i;
// cout<<"*****************DES***********************"<<endl<<endl;
cout<<"Input PlainText:"<<endl;
cin>>str;
//cout<<endl<<"****************************************"<<endl;
cout<<"Input Key:"<<endl;
cin>>key;
//cout<<endl<<"****************************************"<<endl;
Des des;
des.SetKey(key);
des.Cipher(output, str);
cout<<"CipherText:"<<endl;
for(i = 0;i < 8;i++) //输出密文
printf("%02X",output[i]);
printf("\n");
//cout<<endl<<"****************************************"<<endl;
cout<<"Decryption:"<<endl;
des.InvCipher(str, output);
cout<<str<<endl;
//cout<<endl<<"****************************************"<<endl;
return 0;
}
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -