You might be thinking of BitID, which tightly couples payment addresses to identity: https://github.com/bitid/bitid – BitAuth does not use Bitcoin keypairs.
We created BitAuth as a way to avoid coupling payments with identity, which is why the keypairs are independent and include a different prefix (0x02).
>Bitcoin addresses are intended to be single use, disposable keys rather a long term method of identification. A portion of Bitcoin's address design is intended to minimize publicity of EC public keys if at all possible.
A potential work around is to just BitAuth with a HD wallet? Thereby negating any address-reuse issues.
