https://github.com/yawning/obfsclient

A C++11 obfs2/3 Tor managed pluggable transport client
https://github.com/yawning/obfsclient

Last synced: about 2 months ago
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A C++11 obfs2/3 Tor managed pluggable transport client

• Host: GitHub
• URL: https://github.com/yawning/obfsclient
• Owner: Yawning
• License: other
• Archived: true
• Created: 2014-02-03T02:31:52.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2018-11-16T12:05:20.000Z (about 6 years ago)
• Last Synced: 2024-08-03T17:12:11.469Z (5 months ago)
• Language: C++
• Size: 1.03 MB
• Stars: 30
• Watchers: 6
• Forks: 13
• Open Issues: 9
• Metadata Files:
  • Readme: README.md
  • Changelog: ChangeLog
  • License: COPYING

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README

        
## obfsclient - A C++11 obfs2/3 Tor managed pluggable transport client

#### Yawning Angel (yawning at schwanenlied dot me)

> Compile this if you are a obfuscated strong proxy

> who don't need no Python

### What?

This is a C++11 client implementation of the following protocols:

 * [obfs2](https://gitweb.torproject.org/pluggable-transports/obfsproxy.git/blob/HEAD:/doc/obfs2/obfs2-protocol-spec.txt) - The Twobfuscator

   * The shared secret mode is not used in the wild and is unsupported.

 * [obfs3](https://gitweb.torproject.org/pluggable-transports/obfsproxy.git/blob/HEAD:/doc/obfs3/obfs3-protocol-spec.txt) - The Threebfuscator

 * [ScrambleSuit](https://github.com/NullHypothesis/scramblesuit/blob/master/doc/scramblesuit-spec.txt) - *EXPERIMENTAL*

   * This requires tor-0.2.5.x or later for Pluggable Transport arguments.

By design it will only function as a ClientTransportPlugin for Tor.  It does use

a reasonably complete implementation of the Pluggable Transport spec so when

used properly, it will function as a drop in replacement for asn's Python

implementation.

### Building

It currently has the following external dependencies:

 * Compile time only

   * Doxygen (For the documentation)

 * Bundled under src/ext (No need to install)

   * [Google C++ Testing Framework](https://code.google.com/p/googletest/)

   * [easylogging++](https://github.com/easylogging/easyloggingpp)

   * [The Lean Mean C++ Option Parser](http://optionparser.sourceforge.net/)

 * [libevent2](https://www.libevent.org)

 * [OpenSSL](https://www.openssl.org/)

 * [liballium](https://github.com/Yawning/liballium)

Non-standard configure options:

 * --enable-scramblesuit-iat - Enable ScrambleSuit IAT obfuscation

Make Targets:

 * all - Build the obfsclient binary

 * check - Build/Run obfsclient_test

 * docs - Build the doxygen documentation

### Usage

In your torrc:

    UseBridges 1

    Bridge obfs2 ip:port fingerprint

    Bridge obfs3 ip:port fingerprint

    Bridge scramblesuit ip:port password=sharedsecret

    ClientTransportPlugin obfs2,obfs3,scramblesuit exec /path/to/the/binary/obfsclient

### Implementation notes

Like the rest of my C++ code, C++ exceptions and RTTI are not used, and it is

expected that the appropriate compiler flags are passed in to disable these

functions.  The obfsclient binary will assert() on fatal errors (out of memory),

because that's realistically the only safe thing to do.

Caveats:

 * My UniformDH implementation is not quite constant time, though the modular

   exponentiation is.  I do not belive that this is a problem since the

   cryptographic components of obfs3 are intended for obfuscation and not

   secrecy.

 * The UniformDH implementation is glacially slow.  I may be spoiled by using

   Curve25519 so much lately.

### TODO (Patches accepted!)

 * See the [issue tracker](https://github.com/Yawning/obfsclient/issues).

### WON'T DO

 * No, I do not care if this compiles out of the box on Windows.

 * No, I do not care that this doesn't compile with ancient compilers.

 * Unmanaged mode might be a nice to have, but all I care about is Tor.

 * Server implementations of all the protocols (Use the Python version).