RSA Signature with Certificate's Private Key from PFX

Demonstrates how to use a certificate's private key from a PFX file to create an RSA signature.

Download Chilkat Java Library

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;

    //  Create an instance of a certificate store object, load a PFX file,
    //  locate the certificate we need, and use it for signing.
    //  (a PFX file may contain more than one certificate.)
    CkCertStore certStore = new CkCertStore();

    //  The 1st argument is the filename, the 2nd arg is the
    //  PFX file's password:
    success = certStore.LoadPfxFile("chilkat.pfx","test");
    if (success != true) {
        System.out.println(certStore.lastErrorText());
        return;
    }

    CkCert cert;
    cert = certStore.FindCertBySubject("Chilkat Software, Inc.");
    if (cert == null ) {
        System.out.println(certStore.lastErrorText());
        return;
    }

    CkPrivateKey pkey;
    pkey = cert.ExportPrivateKey();
    if (pkey == null ) {
        System.out.println(cert.lastErrorText());
        return;
    }

    String pkeyXml;
    //  Get the private key in XML format:
    pkeyXml = pkey.getXml();

    CkRsa rsa = new CkRsa();

    //  Any string argument automatically begins the 30-day trial.

    success = rsa.UnlockComponent("30-day trial");
    if (success != true) {
        System.out.println("RSA component unlock failed");
        return;
    }

    //  Import the private key into the RSA component:
    success = rsa.ImportPrivateKey(pkeyXml);
    if (success != true) {
        System.out.println(rsa.lastErrorText());
        return;
    }

    //  This example will sign a string, and receive the signature
    //  in a hex-encoded string.  Therefore, set the encoding mode
    //  to "hex":
    rsa.put_EncodingMode("hex");

    String strData;
    strData = "This is the string to be signed.";

    //  Sign the string using the sha-1 hash algorithm.
    //  Other valid choices are "md2" and "md5".
    String hexSig;
    hexSig = rsa.signStringENC(strData,"sha-1");

    System.out.println(hexSig);

    System.out.println("Success!");
  }
}