Limits to Anonymity When Using Credentials (Transcript of Discussion)

Abstract

Rather sadly, I’m afraid, I don’t think my talk will be terribly controversial.

I want to talk about anonymity, a special aspect of privacy, and anonymous credentials. Whilst one might have a scheme which is theoretically secure in some sense, of course there are limits to what that might guarantee you about anonymity, just through the practicalities of using this scheme. Having observed that, what might one do in order to try and maximise the level of anonymity that one achieves in the practical use of a credential scheme? I’m not going to look at scheme-specific issues, I’m not going to look at proofs of security, or details of how particular credential schemes work, but just assume some general properties of credential schemes, and look at what practical implications there are from the use of such schemes. This is based on joint work with a student of mine, Andreas Pashalidis, and as always, this is 90% Andreas and 10that accounts for the 10% of errors that will naturally creep into the talk.