> Yes. I think this limitation could be removed.
> A responding node can have – in theory – multiple identity-keys per
> network interface (network interfaces is also confusing, because you
> could run multiple bitcoind instances on the same interface with
> different ports).
> 
> The BIP should just make clear, that it is probably wise, to use
> different identity-keys for each network interface (ipv4, v6, tor).
> 

I have updated that part of the BIP

-----------
Each peer can configure multiple identity-keys (ECC, 32 bytes). Peers
should make sure, each network interface (IPv4, IPv6, tor) has its own
identity-key (otherwise it would be possible to link a tor address to a
IPvX address).
The identity-public-key(s) can be shared over a different channel with
other node-operators (or non-validating clients) to grant authorized access.
-----------

https://github.com/bitcoin/bips/compare/master...jonasschnelli:2016/07/auth_bip?expand=1

</jonas>