Paper 2007/438

Ordered Multisignatures and Identity-Based Sequential Aggregate Signatures, with Applications to Secure Routing

Alexandra Boldyreva, Craig Gentry, Adam O'Neill, and Dae Hyun Yum

Abstract

We construct two new multiparty digital signature schemes that allow multiple signers to sequentially produce a compact, fixed-length signature. First, we introduce a new primitive that we call \emph{ordered multisignatures} (OMS), which allows signers to attest to a common message as well as the order in which they signed. Our OMS construction substantially improves computational efficiency and scalability over any existing scheme with suitable functionality. Second, we design a new identity-based sequential aggregate signature scheme, where signers can attest to different messages and signature verification does not require knowledge of traditional public keys. The latter property permits savings on bandwidth and storage as compared to public-key solutions. In contrast to the only prior scheme to provide this functionality, ours offers improved security that does not rely on synchronized clocks or a trusted first signer. We provide formal security definitions and support the proposed schemes with security proofs under appropriate computational assumptions. We focus on potential applications of our schemes to secure network routing, but we believe they will find many other applications as well.