UDPack

UDPack is an extensible generic UDP packet obfuscator. The purpose of this application is to sit in the path of a UDP data stream, and obfuscate, deobfuscate or otherwise modify the packets.

Python 3.4 or above is required, since this script uses the asyncio library. Using the latest Python release is always strongly recommended. The basic features require no 3rd-party dependencies, but XChaCha20Poly1305Packer requires PyNaCl.

Warning: It must be stressed that the purpose of this application is obfuscation, not encryption. Many design decisions have been (and will be) deliberately made against best practices in cryptography, so in all likelihood the obfuscation methods will not resist crypto analysis. DO NOT rely on the obfuscation for confidentiality of your data!!!

The current version separates the network part into a separate Manager class and keeps obfuscation in the packers, and use class factory functions instead of mixins to produce derived packers. This makes it easy to chain packers together, as demonstrated in the new PipelineManager.

These packers are available:

• NoOpPacker, CallSoonPacker: doesn't actually obfuscate anything.

• ConstDelayPacker, DelayPacker: delays each datagram for a fixed / variable amount of time.

• RandomDropPacker: drops packets randomly.

• ShufflePacker: shuffles the order of data bytes deterministically, using the random seed as key.

• XorMaskPacker, ReverseOnePlusPacker, XorPtrPosPacker: inspired by the "XOR Patch" for OpenVPN, these 3 packers when combined can emulate any obfuscation method in that patch.

• New: XChaCha20Poly1305Packer: Encrypt each datagram using XChaCha20Poly1305, making the contents indistinguishable from random bytes. 40 bytes overhead for each datagram. Available if PyNaCl is installed.

Typical usage

A "packer" is a particular implementation of obfuscation method, obfuscating packets travelling upstream and deobfuscating packets travelling downstream. An "unpacker" is the same thing, implemented in the opposite direction.

Typically, an unpacker is set up near the server, with its remote_addr pointing to the listening address:port of the server. One or more packer is set up near the client(s), pointing at the listening addr:port of the unpacker. All packers and unpackers should have matching configurations. Finally, clients connect to the packer's listening addr:port. The packer obfuscates any traffic it receives and sends them to the unpacker, which deobfuscate and forward them to the server.

            raw data         obfuscated data           raw data
UDP Client ---------- Packer =============== Unpacker ---------- UDP server
             upstream ==>                      <== downstream

How to use

For this one: write code, not configuration. Simply construct your desired pipeline from the available packers and instantiate your packer. See script.py for an example.