One aspect of cryptography that makes it so fragile is that different constructions have different security properties.
Authenticated encryption schemes are not all equivalent!
You might say “we need authenticated encryption”, choose AES-GCM.
And then later you discover that you want to encrypt more than 4 billion messages per key,
or need key commitment.
every so often i need to render some data in human-typeable form.
sometimes that leads me to my one-word-per-byte encoding.
other times it leads me to the various n characters per m bytes encodings.
one very popular fully encrypted transport protocol over udp
would make traffic analysis of fully encrypted protocols much harder.
got some thinking to do on luggage sizes