• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.959-974
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• 2012

Group signature schemes were made for serving anonymities of signers, but the group signature schemes have been seldomly adapted to the real-world applications because of their low computation and space (i.e. signature length) efficiency, complicated construction, limited user management, and so on. Kang, Hwang, etc. performed the study about the local linkability that is for helping group signature schemes to be adapted more easily to the real world. In this paper, we investigate the nature of local linkability, which did not deal with well in the previous studies, in detail and perform the formal proof for the security of special entities who hold the local linkability.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.3-15
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• 2009

The short group signature introduced by Boneh et al. is one of famous anonymous signature schemes. However, for applying it to the real applications, several restrictions should be considered. The perfect anonymity of users, which is given by group signatures, prevents service providers to provide certain services or resources. For this reason, the local linkability which reduces the anonymity of users has to be provided to the service providers. In addition, the group signature keys, which are one-sidedly assigned from a group manager, cannot support the strong exculpability of users. Hence, the short group signature has to be modified for supporting the strong exculpability. In this paper, we perform a study on the use of the short group signature by proposing a few methods for supporting those two properties.