Add custom QZ Tray fork with pairing key authentication

- Custom fork of QZ Tray 2.2.x with certificate validation bypassed
- Implemented pairing key (HMAC) authentication as replacement
- Modified files: PrintSocketClient.java (certificate check disabled)
- New files: PairingAuth.java, PairingConfigDialog.java
- Excluded build artifacts (out/, lib/javafx*) from repository
- Library JARs included for dependency management

tray/assets/signing/sign-message.php

@@ -0,0 +1,55 @@
+<?php
+/*
+ * Echoes the signed message and exits
+ */
+
+// #########################################################
+// #             WARNING   WARNING   WARNING               #
+// #########################################################
+// #                                                       #
+// # This file is intended for demonstration purposes      #
+// # only.                                                 #
+// #                                                       #
+// # It is the SOLE responsibility of YOU, the programmer  #
+// # to prevent against unauthorized access to any signing #
+// # functions.                                            #
+// #                                                       #
+// # Organizations that do not protect against un-         #
+// # authorized signing will be black-listed to prevent    #
+// # software piracy.                                      #
+// #                                                       #
+// # -QZ Industries, LLC                                   #
+// #                                                       #
+// #########################################################
+
+// Sample key.  Replace with one used for CSR generation
+$KEY = 'private-key.pem';
+//$PASS = 'S3cur3P@ssw0rd';
+
+$req = $_GET['request'];
+$privateKey = openssl_get_privatekey(file_get_contents($KEY) /*, $PASS */);
+
+$signature = null;
+openssl_sign($req, $signature, $privateKey, "sha512"); // Use "sha1" for QZ Tray 2.0 and older
+
+/*
+// Or alternately, via phpseclib
+include('Crypt/RSA.php');
+$rsa = new Crypt_RSA();
+$rsa.setHash('sha512'); // Use 'sha1' for QZ Tray 2.0 and older
+$rsa->loadKey(file_get_contents($KEY));
+$rsa->setSignatureMode(CRYPT_RSA_SIGNATURE_PKCS1);
+$signature = $rsa->sign($req);
+*/
+
+if ($signature) {
+	header("Content-type: text/plain");
+	echo base64_encode($signature);
+	exit(0);
+}
+
+echo '<h1>Error signing message</h1>';
+http_response_code(500);
+exit(1);
+
+?>