[tor-bugs] #8089 [Stegotorus]: Implement the handshake and key exchange as described in the paper

[Tor Bug Tracker & Wiki]

#8089: Implement the handshake and key exchange as described in the paper
----------------------------+-------------------
     Reporter:  vmon        |      Owner:  zwol
         Type:  defect      |     Status:  new
     Priority:  critical    |  Milestone:
    Component:  Stegotorus  |    Version:
   Resolution:              |   Keywords:
Actual Points:              |  Parent ID:  #8099
       Points:              |
----------------------------+-------------------

Comment (by zwol):

 One of the reasons I have been making noises about UDP-based link
 protocols is that it would be nice not to need the special one-block
 cipher for Stegotorus block headers.  If we can transmit the length in
 cleartext we can encrypt the rest of the block header using the same
 authenticated cipher as the payload.  (If the length is encrypted, it
 can't be used to determine the offset to the MAC until it itself is
 authenticated, or you give the attacker a chosen-ciphertext oracle.)  UDP
 would give us cleartext block length for free.  On the other hand, doing
 that might make life harder for steg modules, which now have to conceal a
 decidedly-nonrandom length field somewhere.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8089#comment:9>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online