Provably secure authenticated Diffie-Hellman key exchange for resource-limited smart card

Authenticated Diffie-Hellman key agreement is quite popular for establishing secure session keys. As resource-limited mobile devices arc becoming more popular and security threats are increasing, it is desirable to reduce computational load for these resource-limited devices while still preserving its strong security and convenience for users. In this paper, we propose a new smart-card-based user authenticated key agreement scheme which allows users to memorize passwords, reduces users＇ device computational load while still preserves its strong security. The proposed scheme effectively improves the computational load of modular exponentiations by 50%, and the security is formally proved.     

Comments on enhanced yoking proof protocols for radio frequency identification tags and tag groups

A radio frequency identification (RFID) yoking proof scheme can generate proofs of simultaneous presence of two tags in the range of a specified reader so that an off-line verifier can verify the proofs later. This proof has found several interesting applications. However, many existing RFID yoking schemes are vulnerable to replay attacks. To overcome the weaknesses, Cho et al. proposed a new RFID yoking proof protocol and a new grouping protocol. Unfortunately, Cho et al.’s schemes are still vulnerable to replay attacks. In this paper, in addition to demonstrating weaknesses, we further discuss the rationale behind these weaknesses to provide a guide line for designing secure RFID yoking schemes. Based on the guide line, we propose a new RFID yoking scheme and a new RFID grouping scheme. Performance evaluation shows that our scheme outperforms its counterparts.