How To Ensure Forward and Backward Untraceability of RFID Identification Schemes By Using A Robust PRBG

In this paper, we analyze an RFID identification scheme which is designed to provide forward untraceability and backward untraceability. We show that if a standard cryptographic pseudorandom bit generator (PRBG) is used in the scheme, then the scheme may fail to provide forward untraceability and backward untraceability. To achieve the desired untraceability features, the scheme can use a robust PRBG which provides forward security and backward security. We also note that the backward security is stronger than necessary for the backward untraceability of the scheme.