Mechanisms For Accelerating Online/Offline Signature Verification

Online/offline signatures were first introduced by Even, Goldreich and Micali. As a special digital signature, the property of online/offline signature is that the signing algorithm is divided into two phases. The first phase is performed in the offline phase before the message to be signed is presented, and the second phase is performed in the online phase after the message is given, the signer can generate a signature quickly with the aid of offline tokens. The online phase is very fast. The merit of online/offline signature is that it can reduce the overhead due to that the online signing do simple XOR, addition or multiplication operations and so it does not need complex modular or exponentiations. Short signature scheme from the bilinear pairings were first introduced by Boneh, Lynn and Shacham. These short signature scheme based on bilinear pairings are short and proved. but verifying these signatures is computationally intensive due to the expensive pairing operation.We extend the notion of short signature scheme and the aim is to improve the ef-ficiency of the signature verification. Therefore, we propose a efficient online/offline short signature scheme for multi-signer batch verification, which the cost on verify-ing n signatures of different messages is much less than conducting them one by one; We present an divisible online/offline signature; We also propose an online/offline verification signature which improve the efficiency in "online" verification.