仿射密码加密解密 (输入字母数值)

 import java.util.*;
 public class FangSheMiMa{
     public static void main (String args[]){           
             System.out.println("请依次输入k1,k2,字母数值");             
             Scanner scan=new Scanner (System .in);
             int k1=scan.nextInt();
             int k2=scan.nextInt();
             int letter=scan.nextInt();
                       
            if (gcd(k1,26)!=1){
                System.out.println("输入的密匙不符合要求!");
            }
            else{ 
                     System .out.println("请选择操作");
                     System .out.println("1:加密 ");
                     System .out.println("2:解密 ");                      
                     int t=scan.nextInt();
                     switch (t ){
                     case 1: 
                         System .out.println("明文:"+ letter+"   "+jiaMi(letter,k1,k2));
                         System .out.println("          ");
                         break;
                     case 2:                  
                         System .out.println("密文:"+letter+"   "+jieMi(letter,k1,k2));
                         System .out.println("          ");
                         break;
                                   
                     }
            }
        }
    /* }*/

 
     private static int gcd(int k1, int n) {//  gcd(k1,n)=1为仿射密码具有可逆性的条件
            // TODO Auto-generated method stub
            int k=0;//
            do{
                k=k1%n;
                k1=n;
                n=k;
            }while(k!=0);
                return k1;             
        }  
     //辗转消除求最大公约数
     private static int ni(int k1,int n){
         int i=1;
         while(k1*i%n!=1){
             i++;
         }
        return i;
     }
     
    //加密算法
        private static String jiaMi(int plainText, int k1, int k2) {
            // TODO Auto-generated method stub
            //String PlainText="";
            int encryperText=0;        
            encryperText=(k1*plainText+k2)%26;                        
            String result ="密匙:<"+k1+","+k2+">  "+"   密文:"+encryperText;         
            return result;
        }
     
     
     
//解密算法
    private static String jieMi(int encrypherText, int k1, int k2) {
        // TODO Auto-generated method stub
        int PlainText=0;
        String result="";
        
         // k3(m-t)%26=c
        PlainText=(ni(k1,26)*(encrypherText-k2))%26;              
         result ="密匙:<"+k1+","+k2+">  "+"   明文:"+PlainText;         
        return result;
        
    }
  }