密码加密解密实现

实验（实习）名称 DES加密解密 实验（实习）日期 2013.12 得分 指导教师 专业 年级 3 班次 3 姓名 学号

一、实验目的

了解加密解密过程 二、实验准备 熟悉DES加密解密过程 三、实验要求

完成实验，提交实验报告

四、实验内容： #include #include #include

void show1() //主界面 { printf(\"DES加密解密系统\\n\"); printf(\"1.加密\\n\"); printf(\"2.解密\\n\"); printf(\"3.退出\\n\"); }

void show2() //加密界面 {

printf(\"DES加密\\n\"); printf(\"请选择明文和密钥的输入方式:\\n\"); printf(\"1.直接输入\\n\"); printf(\"2.从文件读取\\n\"); printf(\"3.退出\\n\"); printf(\"\\\选择:\"); }

void reader(char str[30],char s[8]) //读取明文和密钥 { FILE *fp; fp=fopen(str,\"r\"); if(fp==NULL) { printf(\"明文读取失败!\\n\"); } else { fscanf(fp,\"%s\ } fclose(fp); }

void To2Bin(char p[8],int b[]) //将字节转换成二进制流 { int i,k=0; for(i=0;i<8;i++) { int j=0x80; for(;j;j>>=1) { if(j&p[i]) {b[k++]=1;} else { b[k++]=0; } } } }

int IP_Table[] = //初始置换(IP) {

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, , 46, 38, 30, 22, 14, 6 };

int E_Table[] = { //扩展变换E 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}; int S_Box[8][4][16] = {{ {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}}, { {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},

//8个s盒

{ { { { { { {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}, {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}, {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}}, {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}}, { 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}}, {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}}};

int IP_1_Table[] = //逆初始置换IP^-1 { 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, , 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}; int P_Table[32] = //置换运算P { 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}; int PC_1[56] =

{ 56,48,40,32,24,16,8, //密钥置换PC_1 0,57,49,41,33,25,17, 9,1,58,50,42,34,26, 18,10,2,59,51,43,35, 62,,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};

int PC_2[48] = //密钥置换PC_2 { 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,, 29,39,50,44,32,47, 43,48,38,55,33,52, 45,41,49,35,28,31};

void Replacement(int arry1[],int arry2[],int arry3[],int num) 始IP， { int i,tmp; for(i=0;i//置换函数(初始IP，逆初

int move_times[16] = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1}; //对左移位的规定 void lif_move(int arry1[],int arry2[],int n) //左移位实现函数 { int i; for(i=0;i<28;i++) { arry2[i]=arry1[(n+i)%28]; } }

int K[16][48]; //存放16轮子密钥 int c[]; //存放明文或密文

int L[17][32],R[17][32]; //存放加密过程中左右部分 void SubKey(int K0[]) //子密钥产生函数 { int i; int K1[56],K2[56]; int C[17][28],D[17][28];

Replacement(K0,PC_1,K1,56); //密钥置换PC_1 for(i=0;i<28;i++) //将PC_1输出的56比特分为左右两部分 { C[0][i]=K1[i]; D[0][i]=K1[i+28]; } i=0;

while(i<16) { int j; lif_move(C[i],C[i+1],move_times[i]); lif_move(D[i],D[i+1],move_times[i]); for(j=0;j<28;j++) { K2[j]=C[i+1][j]; K2[j+28]=D[i+1][j]; }

Replacement(K2,PC_2,K[i],48); //密钥置换PC_2 i++; } }

void S_compress(int arry[],int shc[]) //S盒压缩变换，其中数组shc存放经过s盒的结果 { int h,l; //行，列 int sha[8]; //存放经过s盒的十进制结果 int i,j; int temp[4];

for(i=0;i<8;i++) //s盒压缩变换 { h=arry[(1+(i*6))-1]*2 + arry[(6+(i*6))-1]; l =arry[(2+(i*6))-1]*8 + arry[(3+(i*6))-1]*4 + arry[(4+(i*6))-1]*2 + arry[(5+(i*6))-1]; sha[i]=S_Box[i][h][l]; }

for(i=0;i<8;i++) {

for(j=3;j>=0;j--) { temp[j]=sha[i]%2; sha[i]=sha[i]/2; }

for(j=0;j<4;j++) { shc[4*i+j]=temp[j]; }

} }

void To10(int a[], int b[],int n)//二进制转十进制 { int i,j; int temp; int arry[16][4]; for(i=0;ivoid To102(int a[], int b[],int n)//二进制转十进制 { int i,j; int temp; int arry[8][8]; int t=1,k; for(i=0;i=0;j--) { if(arry[i][j]==1) { t=1; for(k=0;k<7-j;k++)

}

} { t=t*2; } temp+=t; } }

b[i]=temp;

//F函数

void F_Function(int a[32],int b[32],int n) { int i; int tmp[48]; int tep[32];

Replacement(a,E_Table,tmp,48); //扩展变换E for(i=0;i<48;i++) //与子密钥异或 { tmp[i] ^= K[n][i]; } S_compress(tmp,tep); //压缩变换S Replacement(tep,P_Table,b,32); //置换运算P }

void Encryption(int m0[],int c1[]) { int i,k; int arry[32]; int c0[],m1[];

Replacement(m0,IP_Table,m1,); //初始置换IP for(i=0;i<32;i++) { L[0][i]=m1[i]; R[0][i]=m1[i+32]; } k=1;

while(k<17) { F_Function(R[k-1],arry,k-1); for(i=0;i<32;i++) { L[k][i]=R[k-1][i]; R[k][i]=L[k-1][i]^arry[i]; } k++; }

for(i=0;i<32;i++) { c0[i]=R[16][i]; c0[i+32]=L[16][i]; }

Replacement(c0,IP_1_Table,c1,); //逆初始置换 }

void changeKey(int a[16][48]) { int i,j; int tmp[16][48]; for(i=0;i<16;i++) { for(j=0;j<48;j++) { tmp[i][j]=a[i][j]; } } for(i=0;i<16;i++) { for(j=0;j<48;j++) { K[i][j]=tmp[15-i][j]; } } }

void Decryption(int c1[],int m[]) { int c0[],t[]; int i,k; int arry[32]; changeKey(K); Replacement(c1,IP_Table,c0,); for(i=0;i<32;i++) { L[0][i]=c0[i]; R[0][i]=c0[i+32]; } k=1;

while(k<17) { F_Function(R[k-1],arry,k-1); for(i=0;i<32;i++)

{

//初始IP

L[k][i]=R[k-1][i]; R[k][i]=L[k-1][i]^arry[i]; } k++; }

for(i=0;i<32;i++) { t[i]=R[16][i]; t[i+32]=L[16][i]; }

Replacement(t,IP_1_Table,m,); }

void print() //输出函数 { int i; int a[12],b[12],d[3][16]; int p[],q[]; for(i=0;i<32;i++) { p[i]=L[15][i]; p[32+i]=R[15][i]; q[i]=R[16][i]; q[i+32]=L[16][i]; } To10(K[14],a,48); To10(K[15],b,48); To10(c,d[0],); To10(p,d[1],); To10(q,d[2],); printf(\"\\n\\15轮密钥:\"); for(i=0;i<12;i++) { printf(\"%x\ } printf(\"\15轮结果:\"); for(i=0;i<16;i++) { printf(\"%X\ } printf(\"\\n\\16轮密钥:\"); for(i=0;i<12;i++) { printf(\"%X\ }

//逆初始置换

printf(\"\16轮结果:\"); for(i=0;i<16;i++) { printf(\"%X\}

printf(\"\\n\\最后结果:\"); for(i=0;i<16;i++) { printf(\"%X\ } }

int main() { int num,i,t; char s1[8],s2[8]; int m[]; //m存放二进制明文/密文 int d[]; //存放二进制密钥 int s[8]; show1(); printf(\"\\input you choice:\"); while(1) { scanf(\"%d\ switch(num) { case 1: system(\"cls\"); //调用清屏函数 show2(); { scanf(\"%d\ if(num==1) { while(strlen(s1)!=8) { printf(\"请输入明文(8):\"); scanf(\"%s\ } To2Bin(s1,m); //将明文转换成二进制流 while(strlen(s2)!=8) { printf(\"请输入密钥(8):\"); scanf(\"%s\ } To2Bin(s2,d); //将密钥转换成二进制

SubKey(d); Encryption(m,c); print();

出.....\");

printf(\"按0将此密文解密,1返回上一层,2返回主界面,其他键退scanf(\"%d\if(t==0) { int s[8]; int a[]; Decryption(c,a); To102(a,s,);

printf(\"\\n解密结果:\"); for(i=0;i<8;i++) { printf(\"%c\ } printf(\"\\n按1加密,2解密,3退出\"); } else if(t==1) { system(\"cls\"); show2(); } else if(t==2) { system(\"cls\"); show1(); } else { exit(0); } }

else if(num==2) { char str1[20],str2[20]; printf(\"\\请输入明文文件名:\"); scanf(\"%s\ reader(str1,s1); To2Bin(s1,m); printf(\"\\请输入密钥文件名:\"); scanf(\"%s\

reader(str2,s2); To2Bin(s2,d); SubKey(d);

Encryption(m,c); print();

printf(\"\\n\\按0将此密文解密,1将密文存入文件,2返回主界面,scanf(\"%d\if(t==0) { int a[]; Decryption(c,a); To102(a,s,);

其他键退出.....\");

printf(\"\\n\\解密结果:\"); for(i=0;i<8;i++) { printf(\"%c\ } printf(\"\\n\\按1加密,2解密,3退出\"); }

else if(t==1) { int a[16]; char str[30]; FILE *fw; }

printf(\"\\n\\请输入文件名:\"); scanf(\"%s\fw=fopen(str,\"w\"); if(fw==NULL) { printf(\"\\n\\文件打开失败!\\n\"); } else { To10(c,a,); for(i=0;i<16;i++) { fprintf(fw,\"%X\ } }

fclose(fw);

printf(\"\\n\\密文保存成功!按1加密,2解密,3退出\");

else if(t==2) { system(\"cls\"); show1(); } else { exit(0); } }

else if(num==3) { system(\"cls\"); exit(0); } else {

printf(\"\\n\\输入不正确，请重新输入:\"); } } break; case 2: { system(\"cls\");

printf(\"\\n\\n\\------------------DES解密----------------\"); while(strlen(s1)!=8) {

printf(\"\\n\\n\\n\\请输入密文(8):\"); scanf(\"%s\}

To2Bin(s1,m);

while(strlen(s2)!=8) { printf(\"\\请输入密钥(8):\"); scanf(\"%s\}

To2Bin(s2,d); SubKey(d);

Decryption(m,c); print();

printf(\"\\n\\按1返回上一层,2返回主界面,其他键退出.....\"); scanf(\"%d\if(t==1) {

system(\"cls\");

printf(\"\\n\\n\\---------------DES解密-------------\"); while(strlen(s1)!=8) {

printf(\"\\n\\n\\请输入密文(8):\"); scanf(\"%s\}

To2Bin(s1,m);

while(strlen(s2)!=8) {

printf(\"\\请输入密钥(8):\"); scanf(\"%s\ } To2Bin(s2,d); SubKey(d); Decryption(m,c); print(); } else if(t==2) { system(\"cls\"); show1(); } else { exit(0); } } break; case 3: system(\"cls\"); exit(0); default: printf(\"输入不正确，请重新输入:\"); } } return 0; }

结果：