Java

Duplicate Java Verify RSA Signature

See more RSA Examples

Demonstrates how to duplicate a snippet of Java code that verifies an RSA signature. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  This requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  This example duplicates the following Java code:

    //  import com.sun.org.apache.xml.internal.security.utils.Base64;  
    //  import java.io.ByteArrayInputStream;  
    //  import java.security.PublicKey;  
    //  import java.security.Signature;  
    //  import java.security.cert.CertificateFactory;  
    //  import java.security.cert.X509Certificate;  
    //  public class validateSazetak {  
    //    public static void main(String[] args) {  
    //    String signatureAlgorithm = "SHA256withRSA";  
    //    String base64DataToBeSigned = "Hlp...LE4=";  
    //    String base64Certificate = "MII...TlQ==";  
    //    String base64Signature = "I00...pZA==";  
    //    try {  
    //        CertificateFactory cf;  
    //        X509Certificate certificate = null;  
    //        cf = CertificateFactory.getInstance("X.509");  
    //        certificate = (X509Certificate) cf.generateCertificate(new 
    //        ByteArrayInputStream(Base64.decode(base64Certificate)));  
    //         
    //        Signature signature = Signature.getInstance(signatureAlgorithm, "SunRsaSign");  
    //        PublicKey pk = (PublicKey) certificate.getPublicKey();  
    //        signature.initVerify(pk);  
    //         
    //        byte[] hashBytes = Base64.decode(base64DataToBeSigned);  
    //        signature.update(hashBytes);  
    //         
    //        byte[] sigBytes = Base64.decode(base64Signature);  
    //        boolean validity = signature.verify(sigBytes);  
    //        System.out.println("Is valid signature:" + validity);  
    //      } catch (Exception e) {  
    //          System.out.println(e);  
    //      }  
    //  } 

    String base64DataToBeSigned = "Hlp...LE4=";
    String base64Certificate = "MII...TlQ==";
    String base64Signature = "I00...pZA==";

    CkCert cert = new CkCert();
    success = cert.LoadFromBase64(base64Certificate);
    if (success == false) {
        System.out.println(cert.lastErrorText());
        return;
        }

    CkRsa rsa = new CkRsa();

    success = rsa.SetX509Cert(cert,false);
    if (success == false) {
        System.out.println(rsa.lastErrorText());
        return;
        }

    rsa.put_EncodingMode("base64");
    success = rsa.VerifyStringENC(base64DataToBeSigned,"sha256",base64Signature);
    if (success == false) {
        System.out.println(rsa.lastErrorText());
        return;
        }

    System.out.println("Signature verified.");
  }
}