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DES.cpp
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DES.cpp
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/*******************************************
* Name: myDES.cpp
* Author: kongtaoxing
* Powered by Beijingjiaotong University
******************************************/
#include<iostream>
#include<string>
#include<fstream>
#include<vector>
#include<algorithm>
using namespace std;
// IP置换表
int IP[64] = {
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,
56, 48, 40, 32, 24, 16, 8, 0,
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6
};
// IP逆置换表
int IPni[64] = {
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,
32, 0, 40, 8, 48, 16, 56, 24
};
//S盒
int S[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}
}
};
//扩充置换表E，用于把R从32位扩展到48位
int E[48] = {
31, 0, 1, 2, 3, 4,
3, 4, 5, 6, 7, 8,
7, 8, 9, 10, 11, 12,
11, 12, 13, 14, 15, 16,
15, 16, 17, 18, 19, 20,
19, 20, 21, 22, 23, 24,
23, 24, 25, 26, 27, 28,
27, 28, 29, 30, 31, 0
};
//置换函数P
int P[32] = {
15, 6, 19, 20, 28, 11, 27, 16,
0, 14, 22, 25, 4, 17, 30, 9,
1, 7, 23, 13, 31, 26, 2, 8,
18, 12, 29, 5, 21, 10, 3, 24
};
//置换选择PC1，用以置换密钥
int PC1[56] = {
56, 48, 40, 32, 24, 16, 8,
0, 57, 49, 41, 33, 25, 17,
9, 1, 58, 50, 42, 34, 26,
18, 10, 2, 59, 51, 43, 35,
62, 54, 46, 38, 30, 22, 14,
6, 61, 53, 45, 37, 29, 21,
13, 5, 60, 52, 44, 36, 28,
20, 12, 4, 27, 19, 11, 3
};
//置换选择PC2，移位之后置换密钥
int PC2[56] = {
13, 16, 10, 23, 0, 4, 2, 27,
14, 5, 20, 9, 22, 18, 11, 3,
25, 7, 15, 6, 26, 19, 12, 1,
40, 51, 30, 36, 46, 54, 29, 39,
50, 44, 32, 47, 43, 48, 38, 55,
33, 52, 45, 41, 49, 35, 28, 31
};
//左移次数，用以移动密钥
int MOVE[16] = {
1, 1, 2, 2, 2, 2, 2, 2,
1, 2, 2, 2, 2, 2, 2, 1
};
string encrypt(string p, string k); //加密函数主函数
string decrypt(string c, string k); //解密函数
string LowToUpper(string low); //小写字母转大写字母
string HextoBin(string Hex); //十六进制转二进制
string BintoHex(string Bin); //二进制转十六进制
vector<string> subKey(string k); //子秘钥生成函数
string feistel(string R, string K); //F函数, 不是feistel，起错名了.....
int main()
{
string PATH_P, PATH_C, PATH_K = "";
string p, c, k;
cout << "请输入你想加密还是解密，加密为e，解密为d：";
string ed;
cin >> ed;
cout << "\n请输入需要加解密的文件路径(路径中的单斜杠请输入为双斜杠，以下同)：";
cin >> PATH_P;
ifstream pFile(PATH_P, ios::in);
ifstream kFile;
if(!pFile.is_open()){
cout << "\n打开明文/密文文件失败！" << endl;
system("pause");
return 0;
}
getline(pFile, p); //读入明文/密文字符串
if(p.length() % 16 != 0) {
int temp = 16 - p.length() % 16;
// cout << 16 - p.length() % 16 << endl;
for(int i = 0; i < temp; i++) {
p += "0"; //不够加密的话填0补位，方便加密
// cout << i << endl;
}
}
// cout << "补0后的P：" << p << endl;
pFile.close(); //及时关闭文件，防止内存泄露
cout << "\n请选择准备输入密钥还是选择密钥文件，输入0选择输入密钥， 输入1选择输入密钥文件：";
int miyao;
cin >> miyao;
if(miyao == 0) {
cout << "\n请输入密钥：";
cin >> k;
}
else {
cout << "\n请输入密钥文件路径：";
cin >> PATH_K;
kFile.open(PATH_K, ios::in);
if(!kFile.is_open()) {
cout << "\n打开密钥文件失败！" << endl;
system("pause");
return 0;
}
getline(kFile, k); //读入密钥字符串
kFile.close();
if(k.length() != 16) {
cout << "\n请将密钥长度限制为16位！" << endl;
system("pause");
return 0;
}
}
if(ed == "e") {
c = encrypt(p, k);
ofstream cFile("1_encry.txt",ios::out);
if(!cFile.is_open()) {
cout << "创建/打开1_encry.txt失败，请检查文件是否被占用！" << endl;
system("pause");
return 0;
}
cFile << c;
cFile.close();
cout << "\n密文已保存至程序目录下的1_encry.txt" << endl;
}
else if(ed == "d") {
c = decrypt(p, k);
ofstream cFile("1_decry.txt",ios::out);
if(!cFile.is_open()) {
cout << "创建/打开1_decry.txt失败，请检查文件是否被占用！" << endl;
system("pause");
return 0;
}
cFile << c;
cFile.close();
cout << "\n明文已保存至程序目录下的1_decry.txt" << endl;
}
else {
cout << "参数错误！" << endl;
system("pause");
return 0;
}
// vector<string> K = subKey(k);
// for(int i = 0; i < 16; i++) {
// cout << K[i] << endl;
// }
system("pause");
return 0;
}
string encrypt(string p, string k){ //加密函数
string pBin = HextoBin(p);
vector<string> Key = subKey(k);
// for(int i = 0; i < 16; i++) {
// cout << "K[" << i << "]: " <<Key[i] << endl;
// }
string ans = "";
for(int i = 0; i < pBin.length() / 64; i++) { //采用ECB方式
string _P = pBin.substr(i * 64, 64);
string pIP(64, '0'); //经IP变换之后的字符串
for(int j = 0; j < 64; j++) {
pIP[j] = _P[IP[j]];
}
vector<string> L(17, "00000000000000000000000000000000");
vector<string> R(17, "00000000000000000000000000000000");
L[0] = pIP.substr(0, 32);
R[0] = pIP.substr(32, 32);
// cout << "L[0]: " << L[0] << " R[0]: " << R[0] <<endl;
for(int j = 1; j <= 16; j++) {
L[j] = R[j - 1];
string F = feistel(R[j - 1], Key[j - 1]);
// cout << "F: " << F << endl;
for(int k = 0; k < 32; k++){
R[j][k] = (L[j - 1][k] - '0') ^ (F[k] - '0') + '0';
}
// cout << "L[" << j << "]: " << L[j] << " R[" << j << "]: " << R[j] << endl;
}
string chaIPni = R[16] + L[16], enc(64, '0');
// cout << chaIPni << endl;
for(int j = 0; j < 64; j++) { //IP逆置换
enc[j] = chaIPni[IPni[j]];
}
ans += BintoHex(enc);
}
return ans;
}
string decrypt(string c, string k) { //解密函数
string cBin = HextoBin(c);
vector<string> Key = subKey(k);
reverse(Key.begin(), Key.end());
// for(int i = 0; i < 16; i++) {
// cout << "Revered Key[" << i << "]: " << Key[i] << endl;
// cout << "K: " << Key[i] << endl;
// }
string ans = "";
for(int i = 0; i < cBin.length() / 64; i++) { // 采用ECB模式解码
string _C = cBin.substr(i * 64, 64);
string cIP(64, '0'); // IP置换后的字符串
for(int j = 0; j < 64; j++) {
cIP[j] = _C[IP[j]];
}
// cout << "P: " << c << endl;
// cout << "M: " << _C << endl;
vector<string> L(17, "00000000000000000000000000000000");
vector<string> R(17, "00000000000000000000000000000000");
L[0] = cIP.substr(0, 32);
R[0] = cIP.substr(32, 32);
// cout << "L: " << L[0] << " R: " << R[0] << endl;
for(int j = 1; j <= 16; j++) {
L[j] = R[j - 1];
string F = feistel(R[j - 1], Key[j - 1]);
// cout << "F: " << F << endl;
for(int k = 0; k < 32; k++) {
R[j][k] = (L[j - 1][k] - '0') ^ (F[k] - '0') + '0';
}
// cout << "L: " << L[j] << " R: " << R[j] << endl;
}
string chaIPni = R[16] + L[16], enc(64, '0');
for(int j = 0; j < 64; j++) {
enc[j] = chaIPni[IPni[j]]; // IP逆置换
}
ans += BintoHex(enc);
}
return ans;
}
string LowToUpper(string low) {
for(int i = 0; i < low.length(); i++) {
if(low[i] >= 'a' && low[i] <= 'z') {
low[i] -= 32;
}
}
return low;
}
string HextoBin(string Hex) {
string Bin = "";
for(int i = 0; i < Hex.length(); i++) {
if(Hex[i] == '0') Bin += "0000";
else if(Hex[i] == '1') Bin += "0001";
else if(Hex[i] == '2') Bin += "0010";
else if(Hex[i] == '3') Bin += "0011";
else if(Hex[i] == '4') Bin += "0100";
else if(Hex[i] == '5') Bin += "0101";
else if(Hex[i] == '6') Bin += "0110";
else if(Hex[i] == '7') Bin += "0111";
else if(Hex[i] == '8') Bin += "1000";
else if(Hex[i] == '9') Bin += "1001";
else if(Hex[i] == 'A') Bin += "1010";
else if(Hex[i] == 'B') Bin += "1011";
else if(Hex[i] == 'C') Bin += "1100";
else if(Hex[i] == 'D') Bin += "1101";
else if(Hex[i] == 'E') Bin += "1110";
else Bin += "1111";
}
return Bin;
}
string BintoHex(string Bin) {
string Hex = "";
for(int i = 0; i < Bin.length() / 4; i++) {
int num = (Bin[4 * i] - '0') * 8 + (Bin[4 * i + 1] - '0') * 4 + (Bin[4 * i + 2] - '0') * 2 + (Bin[4 * i + 3] - '0');
if(0 <= num && num <= 9) Hex += (num + '0');
else if(num == 10) Hex += "A";
else if(num == 11) Hex += "B";
else if(num == 12) Hex += "C";
else if(num == 13) Hex += "D";
else if(num == 14) Hex += "E";
else Hex += "F";
}
return Hex;
}
vector<string> subKey(string k) {
string kBin = HextoBin(k);
string kBin1(56, '0');
vector<string> C(16, "0000000000000000000000000000");
vector<string> D(16, "0000000000000000000000000000");
vector<string> K(16, "000000000000000000000000000000000000000000000000");
vector<string> K1(16, "000000000000000000000000000000000000000000000000");
for(int i = 0; i < 56; i++) {
kBin1[i] = kBin[PC1[i]]; //经过PC1置换丢弃8位
}
string C0 = kBin1.substr(0,28);
string D0 = kBin1.substr(28,28);
for(int i = 0; i < 27; i++) {
C[0][i] = C0[i + 1];
D[0][i] = D0[i + 1];
}
C[0][27] = C0[0]; D[0][27] = D0[0];
K[0] = C[0] + D[0];
for(int i = 1; i < 16; i++) { //计算16轮密钥
string tempC = C[i - 1].substr(0, MOVE[i]);
string tempD = D[i - 1].substr(0, MOVE[i]);
for(int j = 0; j < 28 - MOVE[i]; j++) {
C[i][j] = C[i - 1][j + MOVE[i]];
D[i][j] = D[i - 1][j + MOVE[i]];
}
for(int j = 0; j < MOVE[i]; j++) {
C[i][28 - MOVE[i] + j] = tempC[j];
D[i][28 - MOVE[i] + j] = tempD[j];
}
K[i] = C[i] + D[i];
}
for(int i = 0; i< 16;i++){
for(int j = 0; j < 48; j++){ //经过PC2丢弃8位
K1[i][j] = K[i][PC2[j]];
}
}
return K1;
}
string feistel(string R, string K) { //F函数，不是Feistel，起错名了.....Feistel在加密函数里
string _E(48, '0'); //扩展后的R
string F(48, '0');
string ret = "";
// cout << "(E)K: " << K << endl;
for(int i = 0; i < 48; i++) {
_E[i] = R[E[i]];
F[i] = (_E[i] - '0') ^ (K[i] - '0') + '0';
}
// cout << "E(R): " << _E << endl;
// cout << "E(R) XOR K = " << F <<endl;
for(int i = 0; i < 8; i++) { // 经过S盒变换
int x = (F[i * 6] - '0') * 2 + (F[i * 6 + 5] - '0');
int y = (F[i * 6 + 1] -'0') * 8 + (F[i * 6 + 2] - '0') * 4 + (F[i * 6 + 3] - '0') * 2 + (F[i * 6 + 4] - '0');
if(S[i][x][y] >= 0 && S[i][x][y] <= 9) ret += (S[i][x][y] + '0');
else if(S[i][x][y] == 10) ret += "A";
else if(S[i][x][y] == 11) ret += "B";
else if(S[i][x][y] == 12) ret += "C";
else if(S[i][x][y] == 13) ret += "D";
else if(S[i][x][y] == 14) ret += "E";
else ret +="F";
}
// cout << "Right After S-Box: " << ret << endl;
string chaP = HextoBin(ret); //还差P变换
// cout << "Before P: " << chaP << endl;
string ans(32, '0');
for(int i = 0; i < 32; i++) {
ans[i] = chaP[P[i]];
}
// cout << "f: " << ans << endl;
return ans;
}