}
// Get the STS's public and private key
final SignatureKeyCallback.DefaultPrivKeyCertRequest request =
new SignatureKeyCallback.DefaultPrivKeyCertRequest();
final Callback skc = new SignatureKeyCallback(request);
final Callback[] callbacks = {skc};
callbackHandler.handle(callbacks);
final PrivateKey stsPrivKey = request.getPrivateKey();
// Sign the assertion with STS's private key