T-Code itself is just a protocol and has no particular programming language.

Buttplug.io which is part of the same project is written in Rust, but that's another story.

There also is Nogasm which uses a pressure sensor to detect pressure changes in an inflatable buttplug to detect an Orgasm.

The security should be baked into the relay aka. whatever you use to translate the data from a IP based protocol to serial data.

T-Code is designed to be simple to understand, implement and decode by micro controllers over a wired connection and those micro controllers often lack the processing power to do cryptographic security. This relies more on physical security.

Most small microcontrollers can do cryptographic security even in pure software - a c64 6502 can too.