ed25519

It's not made easier by the fact that a lot of cryptography is either very old and arcane or it's one hell of a mess of code that doesn't make sense without reading standards. I had the misfortune of having to dig deep into constructing ASN.1 payloads by hand [1] because that's the only thing Java speaks, and oh holy hell is this A MESS because OF COURSE there's two ways to encode a bunch of bytes (BIT STRING vs OCTET STRING) and encoding ed25519 keys uses BOTH [2]. And ed25519 is a mess in itself. The more-or-less standard implementation by orlp [3] is almost completely lacking any comments explaining what is going on where and reading the relevant RFCs alone doesn't help, it's probably only understandable by reading a 500 pages math paper. It's almost as if cryptographers have zero interest in interested random people to join the field.

If you really know what you are doing you aren't even using NaCl, you use the individual algorithms. For example: https://github.com/orlp/ed25519 .