Fully-Anonymous Short Dynamic Group Signatures Without Encryption

Abstract. Group signatures are an important privacy-enhancing tool which allow members of a group to anonymously produce signatures on behalf of the group. Ideally, group signatures are dynamic and thus allow to dynamically enroll new members to a group. For such schemes Bellare et al. (CT-RSA’05) proposed a strong security model (BSZ model) that preserves anonymity of a group signature even if an adversary can see arbitrary key exposures or arbitrary openings of other group signatures. All previous constructions achieving this strong security notion follow the so called sign-encrypt-prove (SEP) paradigm. In contrast, all known constructions which avoid this paradigm and follow the alternative “without encryption” paradigm introduced by Bichsel et al. (SCN’10), only provide a weaker notion of anonymity (which can be problematic in practice). Until now, it was not clear if constructions following this paradigm, while also being secure in the strong BSZ model, even exist. In this...

• Type: Journal
• Year: 2016
• Where: IACR
• Authors: David Derler, Daniel Slamanig
• Keywords: Biometrics, IACR 2016