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How to Construct Forward Secure Single-Server, Multi-Server and Threshold-Server Assisted Signature Schemes Using Bellare-Miner Scheme

Jia Yu1, Fanyu Kong2, Rong Hao1, Dexiang Zhang3, and Guowen Li4
1. College of Information Engineering, Qingdao University, Qingdao, P. R. China
2. Institute of Network Security, Shandong University, Jinan, P. R. China
3. Network Center, Qingdao University, Qingdao, P. R. China
4. School of Computer Science and Technology, Shandong Jianzhu University, Jinan, P. R. China

Abstract—Server-assisted signature plays an important rolein all kinds of applications in electronic commerce. It can beapplied to the settings where a user employs public networkservers to help her execute digital signature operations. Inthis paper, we discuss a problem of how to constructforward secure single-server, multi-server and thresholdserverassisted signature schemes using Bellare-MinerScheme and propose three signature schemes. In the singleserverassisted signature scheme, the user (signer) canemploy a server to help her produce a signature. In themulti-server assisted scheme, the number of employedservers is increased to n, therefore, it is infeasible for anattacker to forge a valid signature if she can’t corrupt allservers and the signer. In the threshold-server assistedsignature scheme, the generation of a valid signature needsthe cooperation of the user and a quorum of servers. Thescheme is more robust because the system can still get thecorrect signature as soon as no more than threshold serversare corrupted. These three schemes maintain the forwardsecure property, that is, even if the current secret key isexposed, an adaptive chosen-message adversary can’t forgeany signature pertaining to previous time period. Finally,we prove the proposed schemes are correct and forwardsecure.

Index Terms—digital signature, threshold signature, secretsharing, forward security, security analysis

Cite: Jia Yu, Fanyu Kong, Rong Hao, Dexiang Zhang, and Guowen Li, "How to Construct Forward Secure Single-Server, Multi-Server and Threshold-Server Assisted Signature Schemes Using Bellare-Miner Scheme," Journal of Communications, vol. 3, no.7, pp. 28-35, 2008.