Archives
/
obfs4
mirror of https://gitlab.com/yawning/obfs4
2
0
Fork 0
Code Issues Projects Releases Wiki Activity
The obfourscator (obfs4proxy)
You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
87 Commits
1 Branch
14 Tags
520 KiB
Go 100%
 
master
obfs4proxy-0.0.14
obfs4proxy-0.0.13
obfs4proxy-0.0.12
obfs4proxy-0.0.11
obfs4proxy-0.0.10
obfs4proxy-0.0.9
obfs4proxy-0.0.8
obfs4proxy-0.0.7
obfs4proxy-0.0.6
obfs4proxy-0.0.5
obfs4proxy-0.0.4
obfs4proxy-0.0.3
obfs4proxy-0.0.2
obfs4proxy-0.0.1
Branches Tags
${ item.name }
Create tag ${ searchTerm }
Create branch ${ searchTerm }
from '596cc85073'
${ noResults }
Go to file
Yawning Angel 596cc85073 Elide the error out from most logs unless unsafeLogging is set. 
The Golang runtime will happily splatter the remote IP address and port
in the error's string representation for network related errors.  While
useful for debugging, this is unacceptable from a privacy standpoint.
 		10 years ago
common Massive cleanup/code reorg. 10 years ago
doc Change how the length obfsucation mask is derived. 10 years ago
obfs4proxy Elide the error out from most logs unless unsafeLogging is set. 10 years ago
transports Change the drbg seed field in the state file. 10 years ago
.gitignore Move to a unified client/server binary, and fix bugs. 10 years ago
LICENSE Document dependencies, add LICENSE (No functional changes). 10 years ago
README.md Massive cleanup/code reorg. 10 years ago

README.md

obfs4 - The obfourscator

Yawning Angel (yawning at torproject dot org)

What?

This is a look-like nothing obfuscation protocol that incorporates ideas and concepts from Philipp Winter's ScrambleSuit protocol. The obfs naming was chosen primarily because it was shorter, in terms of protocol ancestery obfs4 is much closer to ScrambleSuit than obfs2/obfs3.

The notable differences between ScrambleSuit and obfs4:

  • The handshake always does a full key exchange (no such thing as a Session Ticket Handshake).
  • The handshake uses the Tor Project's ntor handshake with public keys obfuscated via the Elligator 2 mapping.
  • The link layer encryption uses NaCl secret boxes (Poly1305/XSalsa20).

As an added bonus, obfs4proxy also supports acting as an obfs2/3 client and bridge to ease the transition to the new protocol.

Why not extend ScrambleSuit?

It's my protocol and I'll obfuscate if I want to.

Since a lot of the changes are to the handshaking process, it didn't make sense to extend ScrambleSuit as writing a server implementation that supported both handshake variants without being obscenely slow is non-trivial.

Dependencies

Build time library dependencies are handled by go get automatically but are listed for clarity.

Thanks

  • David Fifield for goptlib.
  • Adam Langley for his Elligator implementation.
  • Philipp Winter for the ScrambleSuit protocol which provided much of the design.