加密解密 算法实现程序 c++

#include<iostream.h> #include <stdlib.h> #include<math.h> #include<String.h> int r; //公开模数 int sk; //私人密钥 int pk; //公开密钥 int Euler;//欧拉函数 int check(int x) { for(int i=2;i<=x-1;i++) { if(x%i==0) break; } if(i==x) return 1; else return 0; } void produceSS() { int p,q; int flag=0; int n=0; cout<<"输入值不要太大,防止溢出!"<<endl; while(flag==0) { if(n>0) cout<<"p应为素数，请重新输入!"<<endl; cout<<"请输入素数p:"; cin>>p; flag=check(p); n++; } flag=0; n=0; while(flag==0) { if(n>0) cout<<"q应为素数，请重新输入!"<<endl; cout<<"请输入素数q:"; cin>>q; flag=check(q); n++; } r=p*q; cout<<"公开模数:r="<<r<<endl; Euler=(p-1)*(q-1); cout<<"欧拉函数:Euler="<<Euler<<endl; } int gcd(int x,int y) { int a=x; int b=y; int z; b++; do { b--; x=a; y=b; while(x%y!=0) { z=x%y; x=y; y=z; } }while(z>1); return b; } int trAsc(int s,int a[]) //转为二进制数 { int x=s; int n=0; while(x!=0) { a[n]=x%2; x=x/2; n++; } return n; } int pfc(int x,int key) //平方乘 { int a[13]; int m=trAsc(key,a); //二进制位数 int c=1; for(int i=m-1;i>=0;i--) { c=c*c%r; if(a[i]==1) c=c*x%r; } return c; } int producePk() { int a1=sk; int r1=r; int q1, p1; int b1=0; int b2=1; int b3; do{ cout<<a1<<endl; p1=r1/a1; q1=r1%a1; b3=b1-b2*p1; b1=b2; b2=b3; r1=a1; a1=q1; }while(a1!=1); return abs(b2); } void produceKey() { int k; int n=0; int flag=0; int b1=0; int b2=1; int a,c,q,p; cout<<"初始密钥应小于欧拉函数:"<<r<<endl; cout<<"请输入初始密钥:"; cin>>sk; sk++; do { sk--; sk=abs(sk); sk=gcd(Euler,sk); b1=0; b2=1; a=sk; c=Euler; do { q=c/a; p=c%a; pk=b1-b2*q; c=a; a=p; b1=b2; b2=pk; }while (p!=1); pk=abs(pk); a=pfc(8,sk); c=pfc(a,pk); } while(c!=8); //加密、解密正确判断 cout<<"私人密钥:sk="<<sk<<endl; cout<<"公开密钥:pk="<<pk<<endl; } void Encryption() //加密 { int Express; int flag=1; while(flag) { cout<<"明文编码应小于公开模数r:"<<r<<endl; cout<<"请输入要加密的明文编码(十进制数):"; cin>>Express; if(Express>r) cout<<"明文编码应大于公开模数,请重新输入!"<<endl; else flag=0; } cout<<"sk="<<sk<<endl; cout<<"原编码为:"<<Express; Express=pfc(Express,sk); cout<<"密文为:"<<Express<<endl; } void Decrypt()//减密 { int Express; int flag=1; while(flag) { cout<<"密文编码应小于公开模数r:"<<r<<endl; cout<<"请输入要加密的密文编码(十进制数):"; cin>>Express; if(Express>r) cout<<"密文编码应大于公开模数,请重新输入!"<<endl; else flag=0; } cout<<"pk="<<pk<<endl; cout<<"原编码为:"<<Express; Express=pfc(Express,pk); cout<<"明文为:"<<Express<<endl; } void main() { int flag=1; int step; int n; while(flag) { cout<<"1.产生素数"<<endl; cout<<"2.产生密钥"<<endl; cout<<"3.加密"<<endl; cout<<"4.解密"<<endl; cout<<"5.退出"<<endl; cout<<"请输入您的操作(1,2,3,4或5):"; cin>>step; switch(step) { case 1:produceSS(); break; case 2:produceKey(); break; case 3:Encryption(); break; case 4:Decrypt(); break; case 5:exit(0); break; } } }