/**

 * Encrypts the given message into a PKCS#7 enveloped data blob.


 * The symmetric key algorithm used is Triple DES (3DES) with CBC

 * block mode and PKCS#7 padding.


 * The asymmetric key algorithm used is RSA with ECB block mode and

 * PKCS#1 type 2 padding.

 * 

 * @param recipients an array of X.509 certificates i.e one for each recipient.

 * @param msg the message to be encrypted.

 * 

 * @return the encrypted message.

 * 

 * @throws GeneralSecurityException if <CODE>msg</CODE> cannot be encrypted. There might

 *         be many reasons for this e.g. the parameter <CODE>recipients</CODE> is null or

 *         any given certificate doesn't contain a RSA public key.

 * @throws JCAPIJNIRuntimeException if an unexpected error occur inside MS CAPI.

 */

static public byte[] encryptMessage(X509Certificate[] recipients, byte[] msg)

	throws GeneralSecurityException





/**

 * Decrypts a PKCS#7 enveloped data blob.


 * The recipient's certificate(s) must be stored in the MS CAPI system store MY.

 * 

 * @param encryptedMsg the PKCS#7 encoded enveloped message to be decrypted.

 * 

 * @return the decrypted message.

 * 

 * @throws GeneralSecurityException if <CODE>encryptedMsg</CODE> cannot be encrypted.

 *         There might be many reasons for this e.g. the encrypted message is corrupt,

 *         or no private key can be found, or decryption algorithm is not supported

 *         by the MS CAPI CSP etc.

 * @throws JCAPIJNIRuntimeException if an unexpected error occur inside MS CAPI.

 */

static public byte[] decryptMessage(byte[] encryptedMsg)

	throws GeneralSecurityException

import java.security.*;

import java.security.cert.X509Certificate;

import com.pheox.jcapi.*;





public class Example

{

    public static void main(String[] args)

    {

        try {

            Security.addProvider(new JCAPIProvider());



            KeyStore ks = KeyStore.getInstance("msks", "JCAPI");

            ks.load(null, null);



            String alias = null;

            //Get the alias of first available key entry.

            for(java.util.Enumeration e = ks.aliases(); e.hasMoreElements(); )

                {

                    alias = (String)e.nextElement();

                    if(ks.isKeyEntry(alias))

                        break;

                    else

                        alias = null;

                }



            if(alias == null)

                throw new Exception("No key entry alias found.");



            //Only use one recipient.

            X509Certificate[] recipients = new X509Certificate[1];

            recipients[0] = (X509Certificate)ks.getCertificate(alias);



            //Encrypt message.

            String msg = "This is a secret message.";

            byte[] encryptedData = JCAPICipher.encryptMessage(recipients, msg.getBytes("UTF-8"));



            //Decrypt message.

            byte[] decryptedData = JCAPICipher.decryptMessage(encryptedData);



            //Sanity check.

            if(!msg.equals(new String(decryptedData, "UTF-8")))

                throw new Exception("Decrypted message is not the same as the original message.");

            else

                System.out.println("Test succeded!");



        } catch(Throwable t) {

            System.err.println("Example program failed.");

            t.printStackTrace();

        }

    }

}