import java.math.*;
import java.util.*;
import java.io.*;

public class rsa
{ private static BigInteger one=new BigInteger("1");
  private static int c=0;
  private Random r;
  private BigInteger n, d, e; 

  public rsa()
  { BigInteger p, q, phi, phiminusone, dd, ee;
    c+=1;
    r=new Random(System.currentTimeMillis()+c);
    p=new BigInteger(20,40,r);
    q=new BigInteger(20,40,r);
    n=p.multiply(q);
    phi=p.subtract(one).multiply(q.subtract(one));
    phiminusone=phi.subtract(one);
    dd=new BigInteger(18,40,r);
    ee=dd.modInverse(phi);
    d=dd.min(ee);
    e=dd.max(ee); }

  public rsa(String[] key)
  { n=new BigInteger(key[0]);
    d=new BigInteger(key[1]);
    e=d; }

  public rsa(String[] public_key, String[] private_key)
  { BigInteger dd=new BigInteger(public_key[1]),
               ee=new BigInteger(private_key[1]);
    n=new BigInteger(private_key[0]);
    d=dd.min(ee);
    e=dd.max(ee); }

  public String[] get_private_key()
  { String[] s=new String[2];
    s[0]=n.toString();
    s[1]=e.toString();
    return s; }

  public String[] get_public_key()
  { String[] s=new String[2];
    s[0]=n.toString();
    s[1]=d.toString();
    return s; }

  public static void print_key(String[] s)
  { System.out.print("["+s[0]+","+s[1]+"]"); }

  public BigInteger public_encrypt(BigInteger msg)
  { return msg.modPow(d,n); }

  public BigInteger private_encrypt(BigInteger msg)
  { return msg.modPow(e,n); }

  public static String BigIntegerToString(BigInteger n)
  { return new String(n.toByteArray()); }

  public static BigInteger StringToBigInteger(String s)
  { return new BigInteger(s.getBytes()); }

  public static BigInteger[] StringToBigIntegerArray(String inp)
  { String s;
    BigInteger[] res=new BigInteger[(inp.length()-1)/3+1];
    int i=0;
    while (!inp.equals(""))
    { if (inp.length()>3)
      { s=inp.substring(0,3);
        inp=inp.substring(3); }
      else
      { s=inp;
        inp=""; }
      res[i]=StringToBigInteger(s);
      i+=1; }
    return res; }

  public static String BigIntegerArrayToString(BigInteger[] cod)
  { String s="";
    int i;
    for (i=0; i<cod.length; i+=1)
      s=s+new String(cod[i].toByteArray());
    return s; }

  public static String filter(String s)
  { String r="";
    int i;
    for (i=0; i<s.length(); i+=1)
    { char c=s.charAt(i);
      if (c<32 || c>126) c='~';
      r=r+c; }
    return r; }

  public BigInteger[] private_encrypt(BigInteger[] cod)
  { BigInteger[] res=new BigInteger[cod.length];
    int i;
    for (i=0; i<cod.length; i+=1)
      res[i]=cod[i].modPow(e,n);
    return res; }

  public BigInteger[] public_encrypt(BigInteger[] cod)
  { BigInteger[] res=new BigInteger[cod.length];
    int i;
    for (i=0; i<cod.length; i+=1)
      res[i]=cod[i].modPow(d,n);
    return res; }

  public static void main(String[] args)
  { rsa encoder1=new rsa(), encoder2=new rsa();
    BigInteger[] cod=null;
    String message, s;
    char c;
    int i;
    InputStreamReader ISRin=new InputStreamReader(System.in);
    BufferedReader in=new BufferedReader(ISRin);
    System.out.println("Private key 1 is ["+encoder1.n+","+encoder1.e+"]");
    System.out.println(" Public key 1 is ["+encoder1.n+","+encoder1.d+"]");
    System.out.println("Private key 2 is ["+encoder2.n+","+encoder2.e+"]");
    System.out.println(" Public key 2 is ["+encoder2.n+","+encoder2.d+"]");
    System.out.println("");
    while (true)
    { System.out.println("E to enter a new string, X to exit,");
      System.out.println("B to public(1) encrypt, V to private(1) encrypt.");
      System.out.println("C to public(2) encrypt, W to private(2) encrypt.");
      System.out.print(": ");
      try { s=in.readLine(); } catch (Exception e) { s=" "; }
      c=s.charAt(0);
      if (c=='E' || c=='e')
      { System.out.print("Message: ");
        try { message=in.readLine(); } catch (Exception e) { message="Hello."; }
        cod=StringToBigIntegerArray(message); }
      else if (c=='x' || c=='X')
        System.exit(1);
      else if (c=='b' || c=='B')
        cod=encoder1.public_encrypt(cod);
      else if (c=='v' || c=='V')
        cod=encoder1.private_encrypt(cod);
      else if (c=='c' || c=='C')
        cod=encoder2.public_encrypt(cod);
      else if (c=='w' || c=='W')
        cod=encoder2.private_encrypt(cod);
      else
        System.out.println("Bad input.");
      System.out.println("Message as numbers:");
      for (i=0; i<cod.length; i+=1)
        System.out.println("   "+cod[i]);
      System.out.println("Message as string:");
      s=BigIntegerArrayToString(cod);
      s=filter(s);
      System.out.println("   \""+s+"\"");
      System.out.println(""); } } }