signing keys are stored in hex so encode and decode them

www/common/encode.js

@@ -0,0 +1,19 @@
+define([], function () {
+    var exports = {};
+
+    var hexToUint8Array = exports.hexToUint8Array = function (s) {
+        // if not hex or odd number of characters
+        if (!/[a-fA-F0-9]+/.test(s) || s.length % 2) { throw new Error("string is not hex"); }
+        return s.split(/([0-9a-fA-F]{2})/)
+            .filter(function (x) { return x; })
+            .map(function (x) { return Number('0x' + x); });
+    };
+
+    var uint8ArrayToHex = exports.uint8ArrayToHex = function (a) {
+        return a.reduce(function(memo, i) {
+            return memo + ((i < 16) ? '0' : '') + i.toString(16);
+        }, '');
+    };
+
+    return exports;
+});