title: Security analysis of the unrestricted identity-based aggregate signature scheme.
abstract: Aggregate signatures allow anyone to combine different signatures signed by different signers on different messages into a short signature. An ideal aggregate signature scheme is an identity-based aggregate signature (IBAS) scheme that supports full aggregation since it can reduce the total transmitted data by using an identity string as a public key and anyone can freely aggregate different signatures. Constructing a secure IBAS scheme that supports full aggregation in bilinear maps is an important open problem. Recently, Yuan et al. proposed such a scheme and claimed its security in the random oracle model under the computational Diffie-Hellman assumption. In this paper, we show that there is an efficient forgery on their IBAS scheme and that their security proof has a serious flaw.
authors.affiliation: Center for Information Security Technologies, Korea University, Seoul, Korea.
authors.forename: Kwangsu
authors.initials: K
authors.lastname: Lee
authors.affiliation: Center for Information Security Technologies, Korea University, Seoul, Korea.
authors.forename: Dong Hoon
authors.initials: DH
authors.lastname: Lee
mesh_terms: D000465:Algorithms; D016494:Computer Security / Q000592:standards*; D006801:Humans; D008962:Models, Theoretical