Efficient Sequential Aggregate Signed Data

We generalize the concept of sequential aggregate signatures (SAS), proposed by Lysyanskaya, Micali, Reyzin, and Shacham (LMRS) at Eurocrypt 2004, to a new primitive called

sequential aggregate signed data

(SASD) that tries to minimize the total amount of transmitted data, rather than just signature length. We present SAS and SASD schemes that offer numerous advantages over the LMRS scheme. Most importantly, our schemes can be instantiated with

uncertified

claw-free permutations, thereby allowing implementations based on low-exponent RSA and factoring, and drastically reducing signing and verification costs. Our schemes support aggregation of signatures under keys of different lengths, and the SASD scheme even has as little as 160 bits of bandwidth overhead. Finally, we present a multi-signed data scheme that, when compared to the state-of-the-art multi-signature schemes, is the first scheme with non-interactive signature generation not based on pairings. All of our constructions are proved secure in the random oracle model based on families of claw-free permutations.