用vc++6.0做 的RSA的加密与解密程序

#include<stdio.h> #include<conio.h> #include <math.h> #include <time.h> #include <stdlib.h> #define TIMES 50 #define MAX 100 //素数的范围 #define MIN 1 long Suiji() //随机数生成基本函数 { long i; srand((unsigned)time(NULL)); i = rand()%MAX+MIN; return i; } int Square_and_Multiply(long a,long m,long n) { //m change into bits b……k位(指针数组)bits long d,bits[100],i,k; //k位 d=1; i=0; while(1) //将m转换为二进制，方法为除2取余 { bits[i]=m%2; if(m/2==0)break; m=m/2; i++; } k=i; for(i=k;i>=0;i--) //计算am mod n { d=d*d%n; if(bits[i]==1) d=(d*a)%n; } return d; } int Miller_Rabin(long n) //Miller_Rabin素数测试 //通过测试返回1，否则返回0。n是待测素数,大于3的奇数。 { long a,i,k,m,t; int b; //n-1=2^k m，m为一个奇数，在{2,……,n-1}中随机地选取一个整数a； t=n-1; k=0; while(t%2==0) //算出 k { t=t/2; k++; } m=t; //计算m m=(n-1)/pow(2,k) a=Suiji()%(n-3)+2; //随机取一个a，在{2，n-1}范围内 此方法OK b=Square_and_Multiply(a,m,n); if(b==1) return 1;//n是素数 for(i=0;i<k;i++) { if(b==n-1) return 1; else b=b*b%n; } return 0; } int BeforeMR(long n)////保证n是大于3的奇数才进行 素数测试 { int flag; while(n==3||n==2) return 1; while(n==1) return 0; while(n%2==0) return 0; flag=Miller_Rabin(n);//大于3的奇数才进行 素数测试 return flag; } long MakeNumber()//随机生成大素数 { long p,t; int i,j; start: //sleep(1); p=Suiji(); //随机产生一个数 if(p%2==0)p=p+1; //确保产生的数为奇数 for(i=0;i<TIMES;i++) //素数检验TIMES次 { t=p; j=BeforeMR(t); if(j==0) { printf("\t%ld ",t); goto start; } } return p; } long Make_e(long x) //生成公钥(e,n)中的e { long e,m,n,r; srand((unsigned)time(NULL)); start: e=rand()%x+1; //随机产生一个数e,在1到x之间 m=x; n=e; while((r=m%n)!=0) //判断e是否和n2互为素数 { m=n;n=r; } if(n!=1) //如果不是，返回在重新产生e { goto start; } return e; } long Make_d(long e,long x) //生成私钥d { long d=1; while( (e*d)% x !=1) //d符合的条件为d=e^(-1) mod x d++; return d; } void Encrypt(long ptext) //加密 { long p,q,n,x,e,d; long ctext; p=MakeNumber();//生成p //sleep(1); again: q=MakeNumber();//生成q if(q==p) { goto again;} n=p*q; x=(p-1)*(q-1); e=Make_e(x);////产生公钥e d=Make_d(e,x); //产生私钥d printf("\np = %ld ,q = %ld ",p,q); printf("\npublic key: e = %ld n = %ld ",e,n); printf("\t private key: d = %ld ",d); ctext=Square_and_Multiply(ptext,e,n);//加密，密文=ptext^e mod n if(ctext<0) printf("Erro!Can't work out the result!Please do again!\n");//溢出提示处理 else printf("\nThe ciphertext is: %ld ",ctext); } void Decrypt(long ctext) //解密 { long n,d,ptext; printf("Please input public key : n ="); //输入公钥n scanf("%ld",&n); printf("please input private key: d =");//输入私钥 scanf("%ld",&d); ptext=Square_and_Multiply(ctext,d,n);//解密,明文=ctext ^d mod n printf("The plaintext: %ld ",ptext); } void main() { int i; long ptext,ctext; system("cls"); printf("\t\tR S A"); start: printf("\n1.Encryption.\n2.Decryption.\n0:Exit.\nPlease choose:"); scanf("%d",&i); if(i!=0&&i!=1&&i!=2) { printf("Your choice isn't offered!Please choose again!\n"); goto start; } if(i==1) { printf("\nPlease input the plaintext(only number):"); scanf("%ld",&ptext); Encrypt(ptext); goto start; } if(i==2) { printf("\nPlease input the ciphertext(only number):"); scanf("%ld",&ctext); Decrypt(ctext); goto start; } if(i==0){ exit(0);goto start;} }