'''Protocol header encrypt''' ('''PHE'''), '''Message stream encryption''' ('''MSE''') or '''PHEProtocol header encryption''' is('''PHE''') aare featurefeatures of some [[BitTorrent]] clients that attempts to make BitTorrent hard to throttle. Some [[Internet service provider|ISP]]s throttle BitTorrent traffic because it makes up a large porportion of total traffic and the ISPs don't want to spend money buying extra capacity. Instead, the ISPs spend money on hardware that look for BitTorrent traffic and slow them down.
==History==
TheProtocol featureheader encrypt was conceived by [[RnySmile]] and first implemented in the [[BitComet]] client version 0.60 inon mid[[8 September]] [[2005]]. The BitComet PHE method is not published.
AnMessage alternativestream method of PHEencryption is implemented in [[Azureus]] version 2307-B29.
[[µTorrent]] will implement PHEProtocol header encryption in a later release. [http://forum.utorrent.com/viewtopic.php?pid=44229#p44229]
==Operation==
The BitComet PHE method is not published.
The Azureus method uses either the infohash or a [[D-H]] exchange to establish the key, then it either uses [[RC4]] as the encryption method or just send the message as [[plaintext]].
They are incompatable with each other.
==External link==
*[http://azureus.aelitis.com/wiki/index.php/Message_Stream_Encryption Description on the official Azureus wiki]
