[Terr_]

Neat, I hadn't heard of ring signatures before -- but unfortunately it sounds like it involves (A) a predefined and fixed set of users and (B) all of them already having public keys.

If so, then you can't really use a ring-per-company, because you'd first need an authoritative list of all current employees (whether they have an account or not) and their public keys, and you can't easily add (or drop) employees without creating a new ring.

[vilhelm_s]

I was thinking, each time you register a company email you would get a reply with a list of all the public keys from people who registered with the same email domain. It would mean that the first few people to sign up would have a small anonymity set---but they could wait a bit, and then send another email and get an updated list of the public keys of people who have registered since then. As long as you wait until (say) 100 people have signed up, you'd still have some cover.