From 09a10884370a4e75193652453d5e920cdf75c9b6 Mon Sep 17 00:00:00 2001
From: Mark Qvist <mark@unsigned.io>
Date: Thu, 30 Jun 2022 19:32:08 +0200
Subject: [PATCH] Added description about Fernet modifications

---
 RNS/Cryptography/Fernet.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/RNS/Cryptography/Fernet.py b/RNS/Cryptography/Fernet.py
index b50098e..df6ae56 100644
--- a/RNS/Cryptography/Fernet.py
+++ b/RNS/Cryptography/Fernet.py
@@ -28,8 +28,16 @@ from RNS.Cryptography import PKCS7
 from RNS.Cryptography.AES import AES_128_CBC
 
 class Fernet():
-    FERNET_VERSION            = 0x80
-    FERNET_OVERHEAD           = 48   # In bytes
+    """
+    This class provides a slightly modified implementation of the Fernet spec
+    found at: https://github.com/fernet/spec/blob/master/Spec.md
+
+    According to the spec, a Fernet token includes a one byte VERSION and
+    eight byte TIMESTAMP field at the start of each token. These fields are
+    not relevant to Reticulum. They are therefore stripped from this
+    implementation, since they incur overhead and leak initiator metadata.
+    """
+    FERNET_OVERHEAD  = 48 # Bytes
 
     @staticmethod
     def generate_key():