From 08f03452a94f922c3a9ea44a4a43931a5bb44cb3 Mon Sep 17 00:00:00 2001
From: joe <joe@jerkface.net>
Date: Sun, 29 Oct 2017 19:07:35 -0400
Subject: comments.

---
 src/Network/Tox/Crypto/Transport.hs | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

(limited to 'src')

diff --git a/src/Network/Tox/Crypto/Transport.hs b/src/Network/Tox/Crypto/Transport.hs
index 1583ef6f..f7fd0f7e 100644
--- a/src/Network/Tox/Crypto/Transport.hs
+++ b/src/Network/Tox/Crypto/Transport.hs
@@ -68,9 +68,18 @@ encodeNetCrypto (NetHandshake x)  saddr = (B.cons 0x1a (runPut $ put x),saddr)
 encodeNetCrypto (NetCrypto x)     saddr = (B.cons 0x1b (runPut $ put x),saddr)
 
 data Handshake (f :: * -> *) = Handshake
-    { handshakeCookie :: Cookie
+    { -- The cookie is a cookie obtained by
+      -- sending a cookie request packet to the peer and getting a cookie
+      -- response packet with a cookie in it.  It may also be obtained in the
+      -- handshake packet by a peer receiving a handshake packet (Other
+      -- Cookie).
+      handshakeCookie :: Cookie
+      -- The nonce is a nonce used to encrypt the encrypted part of the handshake
+      -- packet.
     , handshakeNonce :: Nonce24
-    , hadshakeData :: f HandshakeData
+      -- The encrypted part of the handshake packet is encrypted with the long
+      -- term user-keys of both peers.
+    , handshakeData :: f HandshakeData
     }
 
 instance Serialize (Handshake Encrypted) where
@@ -91,7 +100,11 @@ instance Sized HandshakeData where
             <> contramap otherCookie size
 
 data CryptoPacket (f :: * -> *) = CryptoPacket
-    { pktNonce :: Word16
+    { -- | The last 2 bytes of the nonce used to encrypt 'pktData'
+      pktNonce :: Word16
+      -- The payload is encrypted with the session key and 'baseNonce' set by
+      -- the receiver in their handshake + packet number (starting at 0, big
+      -- endian math).
     , pktData :: f CryptoData
     }
 
@@ -148,8 +161,10 @@ erCompat lens = error $ "Use of '" ++ lens ++ "'  lens on incompatible CryptoMes
 typingStatus :: Functor f => (UserStatus -> f UserStatus)-> (CryptoMessage -> f CryptoMessage)
 typingStatus = lens getter setter
   where
+    getter :: CryptoMessage -> UserStatus
     getter (TwoByte TYPING status) = toEnum $ fromIntegral status
     getter _                       = erCompat "typingStatus"
+    setter :: CryptoMessage -> UserStatus -> CryptoMessage
     setter (TwoByte TYPING _) status = TwoByte TYPING (fromIntegral . fromEnum $ status)
     setter _ _                       = erCompat "typingStatus"
 
-- 
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