Simple Digital Signature Example : RSA algorithm « Security « Java Tutorial

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Signature;

import sun.misc.BASE64Encoder;

public class MainClass {
  public static void main(String[] args) throws Exception {
    KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
    kpg.initialize(1024);
    KeyPair keyPair = kpg.genKeyPair();

    byte[] data = "test".getBytes("UTF8");

    Signature sig = Signature.getInstance("MD5WithRSA");
    sig.initSign(keyPair.getPrivate());
    sig.update(data);
    byte[] signatureBytes = sig.sign();
    System.out.println("Singature:" + new BASE64Encoder().encode(signatureBytes));

    sig.initVerify(keyPair.getPublic());
    sig.update(data);

    System.out.println(sig.verify(signatureBytes));
  }
}

36.38.RSA algorithm
	36.38.1.	Basic RSA example.
	36.38.2.	RSA example with random key generation.
	36.38.3.	RSA example with PKCS #1 Padding.
	36.38.4.	RSA example with OAEP Padding and random key generation.
	36.38.5.	An example of using RSA to encrypt a single asymmetric key.
	36.38.6.	Simple Digital Signature Example
	36.38.7.	Creates a 1024 bit RSA key pair and stores it to the filesystem as two files
	36.38.8.	RSA Signature Generation
	36.38.9.	An RSA sample application