How do you implement RSA algorithm in java?

Answer 1

This is a perfectly running code.....

package javaapplication1;

import java.security.*;

import java.io.*;

import javax.crypto.Cipher;

public class NewClass {

public static void main(String args[])

{

String srci="";

try{

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.println("Please enter any string you want to encrypt");

srci=br.readLine();

}

catch(IOException ioe)

{

System.out.println(ioe.getMessage());

}

try

{

KeyPairGenerator kpg=KeyPairGenerator.getInstance("RSA");

kpg.initialize(512);//initialize key pairs to 512 bits ,you can also take 1024 or 2048 bits

KeyPair kp=kpg.genKeyPair();

PublicKey publi=kp.getPublic();

Cipher cipher = Cipher.getInstance("RSA");

cipher.init(Cipher.ENCRYPT_MODE, publi);

byte[]src=srci.getBytes();//converting source data into byte array

byte[] cipherData = cipher.doFinal(src);//use this method to finally encrypt data

String srco=new String(cipherData);//converting byte array into string

System.out.println();

System.out.println("Encrypted data is:-"+srco);

PrivateKey privatei=kp.getPrivate();//Generating private key

Cipher cipheri=Cipher.getInstance("RSA");//Intializing 2nd instance of Cipher class

cipheri.init(Cipher.DECRYPT_MODE, privatei);//Setting to decrypt_mode

byte[] cipherDat = cipheri.doFinal(cipherData);//Finally decrypting data

String decryptdata=new String(cipherDat);

System.out.println("Decrypted data:-"+decryptdata);

}

catch(Exception e)

{

System.out.println(e.getMessage());

}

}

}

Incase of errors mail me on the below given address....

fs.fabianski@gmail.com

-Fabianski Benjamin

India