The Design And Application Of Two Types Of Online/Offline Signatures Schemes

As an important network security technology, the digital signature can provide se-curity services,such as the identification, the integrity, the non-reputation, and so on. For the routing in mobile ad hoc networks (MANET), there are some kinds of solutions, such as ad hoc on-demand distance vector routing (AODV), and dynamic source routing (DSR).But the designs don't take the security into account, such as authentications.The digital signatures can be used in routing protocols to provide security services.But there are some problems when the techniques are adopted by the MANET:(1)the mobile de-vices don't have enough computational ability, while it needs too many computations to generate one signature;(2) when multiple users sign on the same message, the number of signatures would increase as the nodes increases, and the verifying time would increases also, (3) when a new node join in the network, the other nodes have to update their public key lists;the new nodes may join in the network at any time and frequently, so the update may be frequent and results in heavy burden for the MANET.For the first and second problems,we study the online/offline multi-signature scheme. As the combination of online/offline signature and multi-signature, it allows multiple users to efficiently sign on a common message and then generate a single multi-signature. This multi-signature convinces the verifiers who have signed on the message. Most com-putations for the multi-signature are computed before the message is given.After the message is available, only small quantities of computations are needed to generate the multi-signature. This could solve the first problem. For multiple users,there is only one multi-signature, instead of n signatures for n signers,so only one verification is needed. This could solve the second problem. Based on the online/offline signature proposed by Guo, with the method of constructing the multi-signature scheme used by Lu et al.,a concrete online/offline multi-signature is proposed in this paper. It can be proven secure based on the computational Diffie-Hellman problems in the standard model.Then we dis-cuss the DSR protocol and its security requirements,and provide the application in this protocol.Next, the identity-based online/offline signature scheme is discussed. It can be used to solve the problems(1)and (3).It has both the advantages of the identity-based cryp-tography and the online/offline signature schemes:the key certificates are eliminated, and most computations needed for the signatures'generation are computed before the messages are given,so it could generate the signatures efficiently after the messages are available. When the new nodes join in the MANET, other nodes don't have to update the public key list. That could solve problem(1).The generation for a signature doesn't need many computations after the message is given. The scheme's security can be reduced to the strong Diffie-Hellman problems in the random oracle model.It's secure against the existential forgery under the adaptive chosen-message and identity attack. Compared with the existing schemes,this scheme's verification algorithm only requires one pairing operation, so it is more efficient. At last, we discuss the application of this scheme in the AODV.