Search

This paper studies a hybrid system of the public key infrastructure (PKI) and the identity based cryptosystem (IBC). In the hybrid system, an organization runs a private key generator (PKG) and requests a certificate authority to vouch the binding of the PKG's parameters and the organization's distinguished name. Then an authentication scenario is considered where a member of an organization is authenticated by an application server. The whole design pays attention to scalability and adopts caches and password-based protocols for a scalable service and an easy deployment.

A certificateless strong designated verifier signature (CL-SDVS) may provide more convenient deployment than other SDVS schemes since user's public keys can be published freely and no key-escrow problem needed to be worried about. However, there are only several CL-SDVS schemes and their security is doubtable. This paper provides general CL-SDVS schemes and instances, and discusses their security briefly.

Considering one-round AKE, Cremers and Feltz at ESORICS 2012 defined a security model with perfect forward secrecy (PFS). However, in that model Boyd and and Nieto's general attack about PFS is unworkable. This paper extends their model to capture the general attack and shows that a compiled one-round AKE protocol does not achieve the PFS in the extended model. It suggests to withstand the general attack by extra assumptions.