Added hexConverter helper-module

src/helper/hexConverter.js

@@ -0,0 +1,24 @@
+// From https://stackoverflow.com/a/34356351
+
+// Convert a hex string to a byte array
+function hexToBytes(hex) {
+    for (var bytes = [], c = 0; c < hex.length; c += 2)
+        bytes.push(parseInt(hex.substr(c, 2), 16));
+    return bytes;
+}
+
+// Convert a byte array to a hex string
+function bytesToHex(bytes) {
+    for (var hex = [], i = 0; i < bytes.length; i++) {
+        var current = bytes[i] < 0 ? bytes[i] + 256 : bytes[i];
+        hex.push((current >>> 4).toString(16));
+        hex.push((current & 0xF).toString(16));
+    }
+    return hex.join("");
+}
+
+// Specify exports
+module.exports = {
+    hexToBytes,
+    bytesToHex
+}