"An extremely simple CLI that composes well with UNIX pipes"

Just for fun, I occasionally experiment with proposed "post-quantum" encryption solutions and one in particular called Classic McEliece, from the same author (more or less) as the encryption used in age. Its small and compiles quickly. The interface is elegant and seems impossible to screw up. I have rarely seen anyone outside of the author and his followers use file descriptors in compiled programs in this way. I like it.

Three programs, each only does one thing

     usage: cmkeypair 5>publickey 9>secretkey

     usage: cmencrypt <message 4<publickey >ciphertext

     usage: cmdecrypt <ciphertext 8<secretkey >message

To be fair, I should probably add that McEliece arguably fails the "small, copy-pasteable keys" criteria. :)