[fix] uses hmac_sha512 for hasing the token and don't store the key in it anymore

hmac_sha512.py

@@ -0,0 +1,10 @@
+import sys
+import hashlib
+import hmac
+
+key = sys.argv[1]
+message = sys.argv[2]
+
+result = hmac.new(key, digestmod=hashlib.sha512)
+result.update(message)
+print result.hexdigest()