I don't understand this claim. ansible-vault uses AES256 which is anything but homebrew.
I can take AES256 and make it output the image here: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation...
That's not supposed to happen. The part where homebrew diverges from cryptography is that the former involves engineers like us connecting buzzwords together to produce images like the Wikipedia article, the latter involves complex math and rigorous peer review.