Java Signature

to verfiy a sinature Byte

1. You need public key and private key pair

 

KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024);
KeyPair keyPair = kpg.genKeyPair();

 2. to sign using private key

 Signature sig = Signature.getInstance("MD5WithRSA");
 sig.initSign(keyPair.getPrivate());
 sig.update(data);
 byte[] signatureBytes = sig.sign();

 3. to verify using public key

        Signature sig1 = Signature.getInstance("MD5WithRSA");
        sig1.initVerify(keyPair.getPublic());
        sig1.update(data);
        sig1.verify(signatureBytes);

 

Make sure private key and public key are a pair.