One idea is that older (and still trustworthy) tokens become reliable and more valuable, encouraging parties to 1) keep their tokens for a long time and 2) behave themselves. As I recall, both operate with the concept of a token server. In the case of FAUST, tokens are requested unblinded (that is, from a non-Tor IP), but are anonymous and cannot be associated with the requestor after the fact.
If there's other or more recent work, I'd really like to hear about them.
I'm aware of two proposed systems, both largely academic: FAUST and Fair Anonymity:
https://gnunet.org/node/1704
http://arxiv.org/pdf/1412.4707v1.pdf
One idea is that older (and still trustworthy) tokens become reliable and more valuable, encouraging parties to 1) keep their tokens for a long time and 2) behave themselves. As I recall, both operate with the concept of a token server. In the case of FAUST, tokens are requested unblinded (that is, from a non-Tor IP), but are anonymous and cannot be associated with the requestor after the fact.
If there's other or more recent work, I'd really like to hear about them.