Java by API/java.security/Signature

Signature: initSign(PrivateKey privateKey) throws InvalidKeyException

  
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Signature;
import sun.misc.BASE64Encoder;
public class Main {
  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));
  }
}

Signature: sign() throws SignatureException

  
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Signature;
import sun.misc.BASE64Encoder;
public class Main {
  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));
  }
}

Signature: update(byte[] data) throws SignatureException

  
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Signature;
import sun.misc.BASE64Encoder;
public class Main {
  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));
  }
}