"Multimodal Private Signatures" by Khoa Nguyen, Fuchun Guo et al.
We introduce Multimodal Private Signature (MPS) - an anonymous signature system that offers a novel accountability feature: it allows a designated opening authority to learn some partial information op about the signer’s identity id, and nothing beyond. Such partial information can flexibly be defined as op= id (as in group signatures), or as op= 0 (like in ring signatures), or more generally, as op= Gj(id), where Gj(· ) is a certain disclosing function. Importantly, the value of op is known in advance by the signer, and hence, the latter can decide whether she/he wants to disclose that pie...
Source: uow.edu.au