Monke Encryption for Mirror

Monke is a plug and play encrypted transport layer for mirror.

Prevent hackers from spying on your monkey business!

What it does

Monke's a step towards an extra layer of security.
Encrypts outgoing messages and decrypts incoming messages.
Server sends its public key on connect -> client sends his -> everything else after that is encrypted.
"if i sit outside your house and wireshark your internet, all the data from your game will be random garbage to me"

Currently Monke only encrypts everything, which isn't ideal, but can have humorous upsides.
A quote from some Geniuses
Genius1: "y would u want to encrypt player position"
Genius2: "annoy people trying to write bots"
Genius2: "its batched anyways so.. 16 bytes per 1kb message (for unreliable) is nothing really"

Notes

Monke is NOT a full fledged security solution for Mirror, and is best when combined with other obfuscation, authentication and anti tamper methods.
The only thing that's unsecured is the initial hand shake.
If you are using webgl with HTTPS, then the transport will already be encrypted and monke is not needed.

How to use

1. Add Monke.cs to your NetworkManager object.
2. Drag Monke into the NetworkManager Transport field.
3. Drag the transport you want to use (ie. KCP, Telepathy) into the 'Communication Transport' field in Monke.
4. Check the "Debugging" section (For me, linux only worked with Mono Net 4.0, not IL2CPP Net 2.0).

Screenshot demonstration:

Tick the "Show Debug Logs" bool, have a player join server/host, and you will see the following in console:

Debugging

Console error:
Assets/MonkeTransport/Monke.cs(274,9): error CS0227: Unsafe code may only appear if compiling with /unsafe. Enable "Allow 'unsafe' code" in Player Settings to fix this error.

Mac
"libsodium.dylib" cannot be opened because the developer cannot be verified.
Go to System Preferences, Security and Privacy, and click "Allow Anyway".

Linux
"Unable to preload the following plugins: libsodium.so"
"Not supported exception:"
"DllNotFoundException: libsodium"

If your linux server build gives any of the above errors, adjust your Unity settings, and download the right libsodium.so architecture for your linux server. The combination of architectures and Unity settings may need to be experimented with, here is what worked for me on AWS EC2 t2.micro.

Download, unzip, unzip data.tar.xz, locate "libsodium.so", place this in your Plugins/Linux/ Unity folder or overwrite the libsodium.so in the built files. Link for alternative libsodium architectures:
https://packages.debian.org/buster/libsodium23

Sodium.Core.dll code pulled from https://github.com/ektrah/libsodium-core/ .

Other error:
Make sure Mirror is imported, close and reopen Unity, check Player, Scripting define symbols are there, and if you have switched platform too (Unity does not always transfer them between platforms).
Tested and working with Mirror 35.1.0 - 46 LTS - 53, 65, 66, 73, 79 and 82. Other versions likely supported, but it would be silly to test them all! :D

Credits

JesusLuvsYooh
cooper
Derek S
James
John Soros
Mirror team
https://github.com/cxxpxr/monke