Create PKCS1 RSA Signature with PEM Private Key

Demonstrates how to load a private key from a PEM file and create a PKCS1 RSA digital 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[])
  {
    CkPrivateKey pkey = new CkPrivateKey();

    //  Load the private key from an RSA PEM file:
    pkey.LoadPemFile("pvkey2_rsa.pem");

    boolean success;

    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!");
  }
}