DES算法的c++实现
用数组存的位，改天用unsigned int重写下。依然不负责填充。
#include<stdio.h> #include<string.h> int IP_Table[64] = { //IP置换矩阵 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 }; int E_Table[48] = { //扩展矩阵 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 }; int P_Table[32] = { // P 盒 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}; int IPR_Table[64] = { //逆IP置换矩阵 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 }; int PC1_Table[56] = { //密钥第一次置换矩阵 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 }; int PC2_Table[48] = { // 密钥第二次置换矩阵 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 }; int S_Box[8][4][16]={ //8个S盒 三维数组 // 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 }; //把CHAR转换为INT static void CharToBit(const char input[],int output[],int bits){ int i,j; for(j=0;j<8;j++){ for(i=0;i<8;i++){ output[8*j+7-i]=(input[j]>>i)&1; } } }; //把INT转换为CHAR static void BitToChar(const int intput[],char output[],int bits){ int i,j; for(j=0;j<8;j++){ for(i=0;i<8;i++){ output[j]=output[j]*2+intput[i+8*j]; } } }; //异或操作 static void Xor(int *INA,int *INB,int len){ int i; for(i=0;i<len;i++){ *(INA+i)=*(INA+i)^*(INB+i); } }; //初始IP置换，64->64,左右分别32 static void IP(const int input[64],int output[64],int table[64]){ int i; for(i=0;i<64;i++){ output[i]=input[table[i]-1];//减1操作不可少！！ } }; //E扩展32->48 static void E(const int input[32],int output[48],int table[48]){ int i; for(i=0;i<48;i++){ output[i]=input[table[i]-1]; } }; //P置换, static void P(const int input[32],int output[32],int table[32]){ int i; for(i=0;i<32;i++){ output[i]=input[table[i]-1]; } }; //逆IP static void IP_In(const int input[64],int output[64],int table[64]){ int i; for(i=0;i<64;i++){ output[i]=input[table[i]-1]; } }; //PC_1，用于密钥置换 static void PC_1(const int input[64],int output[56],int table[56]){ int i; for(i=0;i<56;i++){ output[i]=input[table[i]-1]; } }; //PC_2 static void PC_2(const int input[56],int output[48],int table[48]){ int i; for(i=0;i<48;i++){ output[i]=input[table[i]-1]; } }; //S盒压缩 static void S(const int input[48],int output[32],int table[8][4][16]){ int i=0; int j=0; int INT[8]; for(;i<48;i+=6){ INT[j]=table[j][(input[i]<<1)+(input[i+5])][(input[i+1]<<3)+(input[i+2]<<2)+(input[i+3]<<1)+(input[i+4])]; j++; } for(j=0;j<8;j++){ for(i=0;i<4;i++){ output[4*j+3-i]=(INT[j]>>i)&1; } } }; //完成DES算法轮变换,就是f函数的内部实现，就是一个异或而已 static void F_func(int input[32],int output[32], int subkey[48]){ int len=48; int temp[48]={0}; int temp_1[32]={0}; E(input,temp,E_Table);//32->48 Xor(temp,subkey,len); S(temp,temp_1,S_Box);//48->32 P(temp_1,output,P_Table);//位数不变 }; //秘钥循环左移 static void RotateL(const int input[28],int output[28], int leftCount){ int i; int len=28;//因为不是位运算，所以可以不用unsigned for(i=0;i<len;i++){ output[i]=input[(i+leftCount)%len]; } }; //子密钥生成 static void subKey_fun(const int input[64],int Subkey[16][48]){//注意输入和输出的位数,int只存放01,密钥为18位16轮 int loop=1,loop_2=2; int i,j; int c[28],d[28]; int pc_1[56]={0}; int pc_2[16][56]={0}; int rotatel_c[16][28]={0}; int rotatel_d[16][28]={0}; PC_1(input,pc_1,PC1_Table); for(i=0;i<28;i++){ c[i]=pc_1[i];//L d[i]=pc_1[i+28];//R } int leftCount=0; for(i=1;i<17;i++){ if(i==1||i==2||i==9||i==16){//左移一位 leftCount+=loop; RotateL(c,rotatel_c[i-1],leftCount); RotateL(d,rotatel_d[i-1],leftCount); } else{//左移两位 leftCount += loop_2; RotateL(c,rotatel_c[i-1],leftCount); RotateL(d,rotatel_d[i-1],leftCount); } } for(i=0;i<16;i++){ for(j=0;j<28;j++){ pc_2[i][j]=rotatel_c[i][j]; pc_2[i][j+28]=rotatel_d[i][j]; } } for(i=0;i<16;i++){ PC_2(pc_2[i],Subkey[i],PC2_Table); } }; //加密实现 static void DES_Efun(char input[8],char key_in[8],int output[64]){ int Ip[64]={0};//存储初始置换后的矩阵 int output_1[64]={0}; int subkeys[16][48]; int chartobit[64]={0}; int key[64]; int l[17][32],r[17][32]; CharToBit(input,chartobit,8);//转换为64个二进制数 IP(chartobit,Ip,IP_Table);//IP初始置换！ CharToBit(key_in,key,8); subKey_fun(key,subkeys); for(int i=0;i<32;i++){ l[0][i]=Ip[i]; r[0][i]=Ip[32+i]; } for(int j=1;j<16;j++){//前15轮的操作 for(int k=0;k<32;k++){ l[j][k]=r[j-1][k]; } F_func(r[j-1],r[j],subkeys[j-1]); Xor(r[j],l[j-1],32); } int t=0; for(t=0;t<32;t++){//最后一轮的操作,合并了将l,r swap r[16][t]=r[15][t]; } F_func(r[15],l[16],subkeys[15]); Xor(l[16],l[15],32); for(t=0;t<32;t++){ output_1[t]=l[16][t]; output_1[32+t]=r[16][t]; } IP_In(output_1,output,IPR_Table); }; //解密实现 static void DES_Dfun(int input[64],char key_in[8],char output[8]){ int Ip[64]={0};//存储初始置换后的矩阵 int output_1[64]={0}; int output_2[64]={0}; int subkeys[16][48]; //int chartobit[64]={0}; int key[64]; int l[17][32],r[17][32]; IP(input,Ip,IP_Table);//IP初始置换 CharToBit(key_in,key,8); subKey_fun(key,subkeys); for(int i=0;i<32;i++){ l[0][i]=Ip[i]; r[0][i]=Ip[32+i]; } for(int j=1;j<16;j++){//前15轮的操作 for(int k=0;k<32;k++){ l[j][k]=r[j-1][k]; } F_func(r[j-1],r[j],subkeys[16-j]); Xor(r[j],l[j-1],32); } int t=0; for(t=0;t<32;t++){//最后一轮的操作 r[16][t]=r[15][t]; } F_func(r[15],l[16],subkeys[0]); Xor(l[16],l[15],32); for(t=0;t<32;t++){ output_1[t]=l[16][t]; output_1[32+t]=r[16][t]; } IP_In(output_1,output_2,IPR_Table); BitToChar(output_2,output,8); }; int main(){ int output[64]={0}; char MIN[9]={0}; char MI[9]={0}; printf("请输入明文\n"); gets(MIN); printf("请输入秘钥\n"); gets(MI); DES_Efun(MIN,MI,output); printf("密文如下:\n"); for(int i=0;i<64;i++){ printf("%d",output[i]); if((i+1)%4==0) printf("\n"); } printf("\n"); printf("解密功能\n"); DES_Dfun(output,MI,MIN); printf("明文如下:\n"); for(int i=0;i<8;i++){ printf("%c",MIN[i]); } printf("\n"); return 0; }
