Opened 4 years ago

Closed 4 years ago

#16745 closed enhancement (invalid)

Update needed to FAQ pluggable transports

Reported by: cypherpunks Owned by: Sebastian
Priority: Medium Milestone:
Component: Webpages/Website Version:
Severity: Keywords: pt
Cc: Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

I can't find any information on the new obfs4 pluggable transports. What are the differences between obfs3 and obfs4? What are the characteristics of them as well as other pluggable transports like flashproxy and meek?

Child Tickets

Change History (4)

comment:1 Changed 4 years ago by dcf

Component: TorWebsite
Keywords: pt added
Owner: set to Sebastian

Hi, what pluggable transports page are you looking at?

https://www.torproject.org/docs/pluggable-transports.html.en is for sure out of date. But it mentions obfs4 and links to a document that describes obfs4.

https://trac.torproject.org/projects/tor/wiki/doc/PluggableTransports#ListofPluggableTransports does not mention obfs4. That one is easy to fix because it is a wiki page.

https://trac.torproject.org/projects/tor/wiki/doc/AChildsGardenOfPluggableTransports has a super-detailed explanation of a few transports, but not all of them.

comment:2 Changed 4 years ago by cypherpunks

Most transports are mentioned but obfs4 is missing on most or not properly explained especially on https://trac.torproject.org/projects/tor/wiki/doc/AChildsGardenOfPluggableTransports where it is not mentioned at all. Also, it is worthwhile to write on why bridges in TBB has obfs3 as "recommended" and not obfs4.

comment:3 in reply to:  2 Changed 4 years ago by dcf

Replying to cypherpunks:

Most transports are mentioned but obfs4 is missing on most or not properly explained especially on https://trac.torproject.org/projects/tor/wiki/doc/AChildsGardenOfPluggableTransports where it is not mentioned at all. Also, it is worthwhile to write on why bridges in TBB has obfs3 as "recommended" and not obfs4.

doc/AChildsGardenOfPluggableTransports is a best-effort page that doesn't attempt to explain everything. It's actually a ton of work to document one protocol in detail for that page. The best way to get something added to that page is to start writing it yourself.

If you know of specific text that you think should be added to specific URLs, let us know on this ticket. Otherwise I will close the ticket because a ticket needs a clear and specific goal.

As I understand it, obfs3 is still the default because there are more obfs3 bridges than obfs4 bridges. The default might change in the future when there are more obfs4 bridges.

As for differences between obfs3 and obfs4, it would be a good question to ask at https://tor.stackexchange.com/. You can find some of the differences in the specification for obfs4, https://gitweb.torproject.org/pluggable-transports/obfs4.git/tree/doc/obfs4-spec.txt:

Unlike obfs3, obfs4 attempts to provide authentication and data integrity...
Like obfs3 and ScrambleSuit, the protocol has 2 phases
ScrambleSuit has been developed with the aim of improving the obfs3 protocol to provide resilience against active attackers and to disguise flow signatures.... ScrambleSuit like the existing obfs3 protocol uses UniformDH for the cryptographic handshake, which has severe performance implications due to modular exponentiation being a expensive operation. Additionally, the key exchange is not authenticated... obfs4 attempts to address these shortcomings...
obfs4 offers protection against passive Deep Packet Inspection...
obfs4 offers protection against active attackers...

comment:4 Changed 4 years ago by dcf

Resolution: invalid
Status: newclosed
Type: defectenhancement

Closing because the request is not specific and there's no one to do it. Reopen the ticket if you have a patch or a specific design for what the documentation should cover.

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