A hash-mode in hashcat is a plugin. It consists of a module that describes and parses the hash, plus kernels that compute it. Adding one does not require patching hashcat itself.

Try a hash recipe first. With -m 4000 you describe the scheme on the command line and hashcat compiles it into a kernel, which covers most custom schemes at close to native speed and takes minutes rather than days. Write a plugin when the recipe language cannot express the algorithm, or when it needs real kernel work.

The Python and Rust routes go through the assimilation bridge and run on the host, so they are suited to slow hashes. They do not translate your code into GPU code.

A separate interface, the feed, plugs in a candidate generator rather than a hash. That is the generic attack.

• docs/hashcat-plugin-development-guide.md is the main guide: plugin structure, the module and kernel interfaces, the crypto library, salts and esalts, the tokenizer and the test suite
• the Python quickstart and development guide, with what it needs installed
• the Rust quickstart and build requirements