A robust identification protocol without a highly reliable trusted center

The author proposes a robust identification scheme without a highly reliable trusted center. The Fiat-Shamir and Fiat-Shamir-like schemes assume the existence of trusted center which can access to a great deal of secret information and can conspire with the special users who want to know other user´s secret information. The proposed scheme reduces the trustworthiness of the trusted center while preserving the efficiency of the scheme. This scheme is based on the difficulty of extracting the L-th roots mod N and the discrete logarithm problem in a subgroup of Z_R*. The user´s secrete information need not be exposed even to the trusted center. Therefore the scheme does not need a highly reliable trusted center and easily updates a user´s secret keys