Function ed25519_pubkey_raw_from_openssh 

pub fn ed25519_pubkey_raw_from_openssh(
    line: &str,
) -> Result<[u8; 32], OpenSshParseError>

Parse a 32-byte ed25519 raw public key from an OpenSSH-format pubkey line ("ssh-ed25519 <base64> [comment]"). Errors when the line isn’t ed25519, the base64 doesn’t decode, or the inner SSH-wire-format (RFC 4253 §6.6: string "ssh-ed25519" || string <32-byte pubkey>) is malformed.