From the folks who brought you ZeroCoin, here is a new paper on anonymous credentials that relies on Bitcoin (actually NameCoin). Such schemes have applicability to all kinds of things we care about like anti-sybil attacks.
http://eprint.iacr.org/2013/622.pdfI haven't really digested it yet, so it's currently not clear to me how it's different or better to anonymous passports/SINs/proofs of sacrifice:
https://en.bitcoin.it/wiki/Identity_protocol_v1I plan to re-read it when I have more time and think about it.
