Greg Kennedy 2022
Verify an ed25519 signature via CLI (C + OpenSSL).
This is a minimal example to verify an ed25519 signature as a command-line tool. Usage is:
ed25519-verify <key> <signature>
The message should be passed on STDIN (via cat, echo, etc). Remember that some Unix tools append a newline by default, and this will cause the signature to differ.
NOTE: proper cleanup of buffers / structures is omitted, be cautious embedding this in any larger project