DES加解密代码实现(C++)
今天花了时间实现了一遍DES算法的加解密全过程。分享一下欢迎交流。
AES的可以参考AES算法代码实现(完整C++源代码)
参考书籍是《密码编码与信息安全:C++实践》
#include <iostream>
#include <string>
#include <vector>
using std::vector;
using namespace std;
/* unsigned long long 类型正好是64bit */
class DES
{
public:
DES();
//~DES();
/* function */
void setKey(unsigned long long k);
void setPlainText(unsigned long long p);
unsigned long long permutations(unsigned long long num, const int p[], int pmax, int n);
void genEncKey();
unsigned long long SBoxes(unsigned long long num);
void encryption();
void decryption();
void showBinary(unsigned long long num);
void showResult();
void getCipherText(){
cout<<"cipherText:"<<cipherText<<endl;
}
void getDeCipherText(){
cout<<"deCipherText:"<<decipherText<<endl;
}
private:
unsigned long long keyShift(unsigned long long k, int n);
unsigned long long key;
unsigned long long plainText;
unsigned long long cipherText;
unsigned long long decipherText;
unsigned long long encKey[16]; //16个子密钥
static const int IP[64];//初始的IP置换
static const int IPI[64];//IP置换的逆置换
static const int keyIP[56];//密钥置换数组
static const int encKeyRound[16];//密钥编排时确定左移位的数组
static const int CP[48]; //压缩置换的数组
static const int EP[48]; //扩展置换的数组
static const int SBox[32][16];
static const int P[32];//S盒运算后的那个置换P
};
/* 构造函数 */
DES::DES(){
key = 0;
plainText = 0;
cipherText = 0;
decipherText = 0;
}
const int DES::IP[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};
const int DES::IPI[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};
const int DES::keyIP[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};
const int DES::encKeyRound[16] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};
const int DES::CP[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};
const int DES::EP[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};
const int DES::SBox[32][16] = {
14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, //S1
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, //S2
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, //S3
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, //S4
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, //S5
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, //S6
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,//S7
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 //S8
};
const int DES::P[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 DES::setKey(unsigned long long k){
key = k;
cout<<"key:"<<key<<endl;
}
void DES::setPlainText(unsigned long long p){
plainText = p;
cout<<"plainText:"<<plainText<<endl;
}
void DES::genEncKey(){
unsigned long long gkey;
gkey = permutations(key, keyIP, 64, 56); //输入64，输出56，并且置换
int i;
for(i=0; i<16; i++){
gkey = keyShift(gkey, encKeyRound[i]);
encKey[i] = permutations(gkey, CP, 56, 48);
}
}
unsigned long long DES::keyShift(unsigned long long k, int n){
unsigned long long tempKey = 0;
unsigned long long L, R;
L = (k&0xFFFFFFF0000000LL)>>28;
//cout<<"L:"<<L<<endl;
R = k&0x0000000FFFFFFF;
if(n == 1){
L = ((L&0x7FFFFFF)<<1) | ((L>>27)&1);
R = ((R&0x7FFFFFF)<<1) | ((R>>27)&1);
tempKey = (L<<28) | R;
}else if(n==2){
L = ((L&0x3FFFFFF)<<2) | ((L>>26)&3);
R = ((R&0x7FFFFFF)<<2) | ((R>>26)&3);
tempKey = (L<<28) | R;
}
return tempKey;
}
unsigned long long DES::permutations(unsigned long long num, const int p[], int pmax, int n){
unsigned long long temp = 0;
int i;
for(i=0;i<n;i++){
temp <<= 1;
temp |= (num >> (pmax - p[i])) & 1;
}
return temp;
}
unsigned long long DES::SBoxes(unsigned long long num){
int i;
unsigned long long temp;
unsigned long long result = 0;
for (i=0; i<8; ++i){
temp = (num >> ((7-i) * 6)) & 0x3F;
int x = ((temp>>4) & 0x2) | (temp & 0x1) + i*4;
int y = (temp>>1) & 0xF;
temp = SBox[x][y];
temp = temp << ((7-i)*4);
result |= temp;
}
return result;
}
void DES::encryption(){
unsigned long long temp = permutations(plainText, IP, 64, 64);
int i;
unsigned long long L, R, tempR;
L = (temp & 0xFFFFFFFF00000000LL) >> 32;
R = (temp & 0x00000000FFFFFFFFLL);
tempR = R;
for(i = 0; i<16; i++){
tempR = permutations(R, EP, 32, 48);
tempR = tempR ^ encKey[i];
tempR = SBoxes(tempR);
tempR = permutations(tempR, P, 32, 32);
tempR ^= L;
L = R;
R = tempR;
cout<<"L["<<i+1<<"]:"<<L<<";R["<<i+1<<"]:"<<R<<endl;
}
temp = (R<<32) | L;
temp = permutations(temp, IPI, 64, 64);
cipherText = temp;
}
void DES::decryption(){
unsigned long long temp = permutations(cipherText, IP, 64, 64);
int i;
unsigned long long L, R, tempR;
L = (temp & 0xFFFFFFFF00000000LL) >> 32;
R = (temp & 0x00000000FFFFFFFFLL);
tempR = R;
for(i = 0; i<16; i++){
tempR = permutations(R, EP, 32, 48);
tempR = tempR ^ encKey[15-i];
tempR = SBoxes(tempR);
tempR = permutations(tempR, P, 32, 32);
tempR ^= L;
L = R;
R = tempR;
}
temp = (R<<32) | L;
temp = permutations(temp, IPI, 64, 64);
decipherText = temp;
}
void DES::showBinary(unsigned long long num){
std::vector<int> v;
do{
v.push_back(num % 2);
num = (num - num%2) / 2;
}while(num != 0);
for(int i=(v.size()-1); i>=0; i--){
cout<<v[i];
}
cout<<endl;
}
int main(int argc, char const *argv[])
{
unsigned long long k = 0b0101010010101010010101001010101001010100101010100101010010101010;
unsigned long long m = 0xFEFEFEFEFEFEFEFE;
//unsigned long long test = 0x55555555555555;
DES des;
des.setKey(k);
des.setPlainText(m);
des.genEncKey();
des.encryption();
des.decryption();
des.getCipherText();
des.getDeCipherText();
//cout<<k<<endl;
return 0;
}
输出结果为：
key:6100781735768380586
plainText:18374403900871474942
L[1]:4294967295;R[1]:1632917792
L[2]:1632917792;R[2]:2794232727
L[3]:2794232727;R[3]:3795282343
L[4]:3795282343;R[4]:3748983394
L[5]:3748983394;R[5]:4062217110
L[6]:4062217110;R[6]:1641708390
L[7]:1641708390;R[7]:1749913032
L[8]:1749913032;R[8]:1488864349
L[9]:1488864349;R[9]:2383402480
L[10]:2383402480;R[10]:845428636
L[11]:845428636;R[11]:2595733769
L[12]:2595733769;R[12]:1263027870
L[13]:1263027870;R[13]:1821615368
L[14]:1821615368;R[14]:3372671493
L[15]:3372671493;R[15]:2828711648
L[16]:2828711648;R[16]:419162872
cipherText:1169819853609965503
deCipherText:18374403900871474942
[Finished in 0.2s]
[1] 王静文, 吴晓艺. 密码编码与信息安全:C++实践[M]. 清华大学出版社, 2015.