BitTorrent protocol encryption: Difference between revisions

Revision as of 01:59, 15 February 2006

Revision as of 05:18, 16 February 2006

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The specification allows the users to choose between encrypting the headers only or the full connection. Encrypting the full connection provides more obfuscation but uses more CPU time. However, PE in µTorrent beta 1.4.1 build 417 or later only supports full encryption for outgoing connections, but will accept both obfuscation levels for incoming connections.

To ensure compatibility with other clients that don't support this specification users may also choose whether unencrypted incoming or outgoing connections are still allowed.

All supported clients will enable encryption automatically if thethey receive otheran peerencrypted requestsincoming itconnection even if outgoing encryption is disabled.

Supported clients propagate the fact that they have MSE/PE enabled through [[peer exchange|PEX]] and [[Distributed hash table|DHT]]. Other clients will then connect to them with encryption even if outgoing encryption is disabled.

==Security==

The estimated strength of the encryption is around 60-80 bits symmetrical (see [http://www.faqs.org/rfcs/rfc3526.html RFC3526] chapter 8). This is quite low for today's standards but one has to keep in mind that this protocol wasn't designed as a secure transport protocol but as fast and efficient obfuscation method. [[Advanced Encryption Standard|AES]] was proposed as the encryption method but not adopted because it is too slow.