Generate RSA key pair and encode private as string

Question

Ello guys,

i am supposed to generate 512 RSA keypair and then encode my public key as a string. I cant find any good tutorial for someone who just begins with encryption....please advices, sample codes,help urgent!!

Answer 1

The Google search term "RSA encryption key java" returned this result about RSA key generation in Java.

Answer 2

For output as Hex-String

import java.security.*;
public class Test {
    public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchProviderException {
        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
        keyGen.initialize(512);
        byte[] publicKey = keyGen.genKeyPair().getPublic().getEncoded();
        StringBuffer retString = new StringBuffer();
        for (int i = 0; i < publicKey.length; ++i) {
            retString.append(Integer.toHexString(0x0100 + (publicKey[i] & 0x00FF)).substring(1));
        }
        System.out.println(retString);
    }
}

For output as byte values

import java.security.*;
import java.security.*;
public class Test {
    public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchProviderException {
        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
        keyGen.initialize(512);
        byte[] publicKey = keyGen.genKeyPair().getPublic().getEncoded();
        StringBuffer retString = new StringBuffer();
        retString.append("[");
        for (int i = 0; i < publicKey.length; ++i) {
            retString.append(publicKey[i]);
            retString.append(", ");
        }
        retString = retString.delete(retString.length()-2,retString.length());
        retString.append("]");
        System.out.println(retString); //e.g. [48, 92, 48, .... , 0, 1]
    }
}