整个加解密过程还未完全理解,暂时留个记号,以后有机会再慢慢体会。
代码如下:
//
// main.cpp
// DES算法
//
// Created by CharlesYan on 2021/4/13.
//#include <iostream>
#include <stdio.h>
#include<stdlib.h>#include "des.h"using namespace std;
//16-wheel secret key structural body
struct Secret_Key {int subKey[56] = {};int C[28];int D[28];
}Secret_KeyOf16[17];//save the 16-wheel sercet key,and the zero flag in order to save the first substitution selection.// save the process of encryption
struct Encryption {int select_Operation[48];int secretKey_Operation[48];int boxOf_S[32];int L[32];int R[32];
}Encryption_Pro[17];int result_Secret[64] = {};//substitution selection table 1(置换选择1)
static int subSelect_table1[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
};
//substitution selection table 2(置换选择2)
static int subSelect_table2[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
};
//Move left shift bits table(循环左移位数表)
static int moveLeft_table[17] = { 0,1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1 };
//initial substitution IP
static int init_subIP[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
};
//selection operation E
static int sel_E[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
};
// Box of S 3D array
static int BoxOf_S[8][4][16] = {//S114, 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,//S215, 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,//S310, 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,//S47,13,14, 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,//S52,12, 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,//S612, 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,//S74,11, 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,//S813, 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
};
//substitution IP
static char P_Table[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
};const int IPR_Table[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
};//Convert an 8-byte key or plaintext to 64-bit binary
int* ChangeToBit(char code[], int n);
//Subfunction:change Byte to 8-bit binary
int* Change_bit(int a);
//create 16-wheel secret key and save them to Secret_KeyOf16
void set_16wheelKey(int* bit_SecretKey);
//the first step of encryption,set R0, as we know, we will not need L0 later.
void first_StepEncryption(int* bit_PlainText);
//encryption, return the result of encryption
void other_StepEncrtption(int flag);
//Box of S operation
void Box_operation(int* a, int n);
// Box of S change byte to bit
int* Change_bit_S(int a);
//IPR_table operation
void IPR_Operation(int result[]);
void print(int flag);
void Pri_ChangeToByte(int secretKey[]);
void desTest() {char my_Plaintext[9] = {};//save plaintext and the last one is '\0'char my_SecretKey[9] = {};//save secretkeycout << "Please input the plaintext of 8 byte:" << endl;cin.get(my_Plaintext, 9);cin.get();// getchar();cout << "Please input the secret key of 8 byte" << endl;cin.get(my_SecretKey, 9);printf("\n");//8-byte SecretKey turn into 64-bit binaryint* bit_SecretKey = ChangeToBit(my_SecretKey, 8);//create 16-wheel secret key.set_16wheelKey(bit_SecretKey);//8-byte SecretKey turn into 64-bit binaryint* bit_Plaintext = ChangeToBit(my_Plaintext, 8);//Encryptionfirst_StepEncryption(bit_Plaintext);other_StepEncrtption(0);//the 0 is meant encryptionIPR_Operation(result_Secret);print(0);//Decryptionfirst_StepEncryption(result_Secret);other_StepEncrtption(1);//the 1 is meant decryption.IPR_Operation(result_Secret);print(0);Pri_ChangeToByte(result_Secret);
}
int* ChangeToBit(char code[], int n) {static int BinaryText[64] = {};int k = 0;for (int i = 0; i < n; i++) {int* temp = Change_bit(code[i]);for (int j = 0; j < n; j++) {BinaryText[k++] = temp[j];}}return BinaryText;
}
int* Change_bit(int a) {static int flag[8] = {};int k = 7;while (a / 2 != 0) {flag[k--] = a % 2;a = a / 2;}flag[k] = 1;return flag;
}
int* Change_bit_S(int a) {static int flag[4] = { 0 };int k = 0;while (a / 2 != 0) {flag[k++] = a % 2;a = a / 2;}if (a == 1)flag[k] = 1;return flag;
}
void set_16wheelKey(int* bit_SecretKey) {//substitution selection 1for (int i = 0; i < 56; i++) {Secret_KeyOf16[0].subKey[i] = bit_SecretKey[subSelect_table1[i] - 1];}//C0 D0for (int i = 0; i < 28; i++) {Secret_KeyOf16[0].C[i] = Secret_KeyOf16[0].subKey[i];Secret_KeyOf16[0].D[i] = Secret_KeyOf16[0].subKey[i + 28];}for (int i = 1; i < 17; i++) {if (moveLeft_table[i] == 1) {for (int j = 0; j < 27; j++) {Secret_KeyOf16[i].C[j] = Secret_KeyOf16[i - 1].C[j + 1];Secret_KeyOf16[i].D[j] = Secret_KeyOf16[i - 1].D[j + 1];}Secret_KeyOf16[i].C[27] = Secret_KeyOf16[i - 1].C[0];Secret_KeyOf16[i].D[27] = Secret_KeyOf16[i - 1].D[0];}else {for (int j = 0; j < 26; j++) {Secret_KeyOf16[i].C[j] = Secret_KeyOf16[i - 1].C[j + 2];Secret_KeyOf16[i].D[j] = Secret_KeyOf16[i - 1].D[j + 2];}Secret_KeyOf16[i].C[26] = Secret_KeyOf16[i - 1].C[0];Secret_KeyOf16[i].C[27] = Secret_KeyOf16[i - 1].C[1];Secret_KeyOf16[i].D[26] = Secret_KeyOf16[i - 1].D[0];Secret_KeyOf16[i].D[27] = Secret_KeyOf16[i - 1].D[1];}}//subKey1 ... subKey16for (int i = 1; i < 17; i++) {int flag[56] = {};for (int j = 0; j < 28; j++) {flag[j] = Secret_KeyOf16[i].C[j];flag[j + 28] = Secret_KeyOf16[i].D[j];}for (int j = 0; j < 48; j++) {Secret_KeyOf16[i].subKey[j] = flag[subSelect_table2[j] - 1];}}//print the result of secret key.for (int i = 1; i < 17; i++) {printf("N = %d\n", i);printf("C%d:", i);for (int j = 0; j < 28; j++) {printf("%d", Secret_KeyOf16[i].C[j]);}printf("\n");printf("D%d:", i);for (int j = 0; j < 28; j++) {printf("%d", Secret_KeyOf16[i].D[j]);}printf("\n");printf("子密钥%d:", i);for (int j = 0; j < 48; j++) {if (j % 8 == 0 && j) printf(" ");printf("%d", Secret_KeyOf16[i].subKey[j]);}printf("\n\n");}
}
void first_StepEncryption(int* bit_PlainText) {for (int i = 0; i < 32; i++) {Encryption_Pro[0].L[i] = bit_PlainText[init_subIP[i] - 1];Encryption_Pro[0].R[i] = bit_PlainText[init_subIP[i + 32] - 1];}
}
void other_StepEncrtption(int flag) {for (int i = 1; i < 17; i++) {for (int j = 0; j < 48; j++) {//selectionEncryption_Pro[i].select_Operation[j] = Encryption_Pro[i - 1].R[sel_E[j] - 1];//secretion operationif (flag == 0)Encryption_Pro[i].secretKey_Operation[j] = Secret_KeyOf16[i].subKey[j] ^ Encryption_Pro[i].select_Operation[j];elseEncryption_Pro[i].secretKey_Operation[j] = Secret_KeyOf16[17 - i].subKey[j] ^ Encryption_Pro[i].select_Operation[j];}// Box of SBox_operation(Encryption_Pro[i].secretKey_Operation, i);// XOR operationfor (int j = 0; j < 32; j++) {Encryption_Pro[i].L[j] = Encryption_Pro[i - 1].R[j];Encryption_Pro[i].R[j] = Encryption_Pro[i - 1].L[j] ^ Encryption_Pro[i].boxOf_S[P_Table[j] - 1];}}
}
void Box_operation(int* a, int n) {int sum = 0;for (int i = 0; i < 48; i += 6) {int flag1 = BoxOf_S[i / 6][a[i] * 2 + a[i + 5]][a[i + 1] * 8 + a[i + 2] * 4 + a[i + 3] * 2 + a[i + 4]];int flag[4] = { 0 };int k = 0;while (flag1 / 2 != 0) {flag[k++] = flag1 % 2;flag1 = flag1 / 2;}if (flag1 == 1)flag[k] = 1;for (int j = 3; j >= 0; j--) {Encryption_Pro[n].boxOf_S[sum++] = flag[j];}}
}
void IPR_Operation(int result[]) {int temp[64] = {};for (int i = 0; i < 32; i++) {temp[i] = Encryption_Pro[16].R[i];temp[32 + i] = Encryption_Pro[16].L[i];}for (int i = 0; i < 64; i++) {result[i] = temp[IPR_Table[i] - 1];}
}
void print(int flag) {for (int i = 1; i < 17; i++) {printf("\nN = %d\n", i);printf("选择运算:");for (int j = 0; j < 48; j++) {if (j % 8 == 0 && j) printf(" ");printf("%d", Encryption_Pro[i].select_Operation[j]);}printf("\n子密钥加:");for (int j = 0; j < 48; j++) {if (j % 8 == 0 && j) printf(" ");printf("%d", Encryption_Pro[i].secretKey_Operation[j]);}printf("\nS盒:");for (int j = 0; j < 32; j++) {if (j % 8 == 0 && j) printf(" ");printf("%d", Encryption_Pro[i].boxOf_S[j]);}printf("\nL:");for (int j = 0; j < 32; j++) {if (j % 8 == 0 && j) printf(" ");printf("%d", Encryption_Pro[i].L[j]);}printf("\nR:");for (int j = 0; j < 32; j++) {if (j % 8 == 0 && j) printf(" ");printf("%d", Encryption_Pro[i].R[j]);}printf("\n");}printf("\n");if (flag == 0)cout << "the result of secret text: " << endl;elsecout << "the result of plain text: " << endl;for (int i = 0; i < 64; i++) {if (i % 8 == 0 && i != 0) printf(" ");printf("%d", result_Secret[i]);}printf("\n");
}
void Pri_ChangeToByte(int secretKey[]) {char temp[8] = {};int k = 0;for (int i = 0; i < 64; i += 8) {int sum = 0;for (int j = i; j < i + 8; j++) {sum += secretKey[j] * pow(2, 7 - j % 8);}temp[k++] = sum;}cout << "the plaintext of 8 byte is :" << endl;for (int i = 0; i < 8; i++) {printf("%c", temp[i]);}printf("\n");
}
参考链接:
https://blog.csdn.net/VistorsYan/article/details/115836524