[tor-dev] HSDir hash ring modification

[Kang]

Hello.
I was reading about hidden services and a thought occurred to me
regarding the hash ring used in choosing and determining the HSDirs
for a hidden service.
As far as I can tell the hash ring is more or less static since a
relay's position is determined by their identity key, which doesn't
change.
I'm also under the impression that the hash ring is only used for
calculation of HSDirs of hidden services.

I don't have a particular method in mind, but it seems to me that you
could use the "time-period" value that is used in calculation of the
service's descriptor-id to shuffle the ring.
This would cause the ring to be different for each hidden service, and
also make its order change periodically.
I imagine in particular it would make onion address enumeration
attacks more difficult, since an attacker wouldn't just be able to
"cast a net" over the ring for all services.

Can anybody see any problems or false assumptions with this?

Thanks