Use Certificate and Private Key PEM Files to Create a Digital Signature

Demonstrates how to load a digital certificate from a PEM file, load it's corresponding private key from a PEM file, save the private key to a key container (if necessary), link the certificate to the key container, and use it to create a digital signature.

 Chilkat Java Library Downloads for Windows, Linux, and MAC OS X

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[])
  {
    CkCert cert = new CkCert();

    //  Load the cert from a PEM file;
    cert.LoadFromFile("cert.pem");

    CkPrivateKey pkey = new CkPrivateKey();

    //  Load the private key from an RSA PEM file:
    pkey.LoadPemFile("pkey_rsa.pem");

    boolean success;

    success = cert.SetPrivateKey(pkey);
    if (success != true) {
        System.out.println(cert.lastErrorText());
        return;
    }

    //  Use Chilkat Crypt (a non-freeware component) to create
    //  a digital signature using the certificate w/ private key:
    CkCrypt2 crypt = new CkCrypt2();

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

    success = crypt.UnlockComponent("30-day trial");
    if (success != true) {
        System.out.println(crypt.lastErrorText());
        return;
    }

    //  Tell the crypt component to use this cert.
    crypt.SetSigningCert(cert);

    //  A PKCS7 signature for any type of file content can be created:
    success = crypt.CreateP7S("license.rtf","license.p7s");
    if (success == false) {
        System.out.println(crypt.lastErrorText());
        return;
    }

    System.out.println(crypt.lastErrorText());

    //  Verify and restore the original file:
    crypt.SetVerifyCert(cert);

    success = crypt.VerifyP7S("license.rtf","license.p7s");
    if (success == false) {
        System.out.println(crypt.lastErrorText());
        return;
    }

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


  }
}