generalize version numbers

lib/AuthMessage.js

@@ -3,15 +3,27 @@
 var Message = require('./Message');
 var ECIES = require('./ECIES');
 
+
+var majorVersion = 1;
+var minorVersion = 0;
+
 /* Encrypted, authenticated messages to be shared between copayers */
 var AuthMessage = function() {
 };
 
+AuthMessage.setVersion = function(major, minor) {
+  majorVersion = major;
+  minorVersion = minor;
+};
+
 AuthMessage.encode = function(topubkey, fromkey, payload, opts) {
-  var version1 = new Buffer([1]); //peers will reject messges containing not-understood version1
-                                  //i.e., increment version1 to prevent communications with old clients
-  var version2 = new Buffer([0]); //peers will not reject messages containing not-understood version2
-                                  //i.e., increment version2 to allow communication with old clients, but signal new clients
+  //peers should reject messges containing bigger major version
+  //i.e., increment to prevent communications with old clients
+  var version1 = new Buffer([majorVersion]);
+
+  //peers should not reject messages containing not-understood minorversion
+  //i.e., increment to allow communication with old clients, but signal new clients
+  var version2 = new Buffer([minorVersion]);
 
   if (opts && opts.nonce && Buffer.isBuffer(opts.nonce) && opts.nonce.length == 8) {
     var nonce = opts.nonce;
@@ -83,11 +95,11 @@ AuthMessage.decode = function(key, encoded, opts) {
     throw new Error('No data present');
   }
 
-  if (version1 !== 1) {
+  if (version1 !== majorVersion) {
     throw new Error('Invalid version number');
   }
 
-  if (version2 !== 0) {
+  if (version2 !== minorVersion) {
     //put special version2 handling code here, if ever needed
   }