## Cryptology ePrint Archive: Report 2012/271

Homomorphic Signature for Identity Authentication in Cloud Computing

Zhiwei Wang, Guozi Sun and Danwei Chen

Abstract: In this paper, we introduce a new kind of homomorphic signature, which is suitable for identity authentication in cloud computing. User firstly gives his full signature (involves all his identity attributes) to the identity authentication server. During the valid period of his full signature, if the user wants to require a cloud service on a special identity (only involves part of identity attributes), he only needs to secretly send a $\{0,1\}^n$ vector to the identity authentication server. The identity authentication server who doesn't know the secret key can compute the partial signature on the special identity, and then signs it to the cloud server. We give a formal secure definition of this homomorphic signature, and construct a scheme from GHR signature. We prove that our scheme is secure under strong RSA assumption.

Category / Keywords: cryptographic protocols / homomorphic signature; identity authentication; cloud computing; GHR signature; strong RSA assumption

Date: received 13 May 2012, last revised 30 May 2012, withdrawn 30 May 2012

Contact author: zhwwang at njupt edu cn

Available format(s): (-- withdrawn --)

Short URL: ia.cr/2012/271

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