ECDSA: add missing class variables for deterministic ECDSA

phpseclib/Crypt/ECDSA.php

@@ -98,6 +98,27 @@ abstract class ECDSA extends AsymmetricKey
      */
     private $curveName;
 
+    /**
+     * Curve Order
+     *
+     * Used for deterministic ECDSA
+     *
+     * @var \phpseclib\Math\BigInteger
+     */
+    protected $q;
+
+    /**
+     * Alias for the private key
+     *
+     * Used for deterministic ECDSA. AsymmetricKey expects $x. I don't like x because
+     * with x you have x * the base point yielding an (x, y)-coordinate that is the
+     * public key. But the x is different depending on which side of the equal sign
+     * you're on. It's less ambiguous if you do dA * base point = (x, y)-coordinate.
+     *
+     * @var \phpseclib\Math\BigInteger
+     */
+    protected $x;
+
     /**
      * Context
      *