Perfect Forward Secure Two-Party Key Agreement Protocol with Key Escrow

Authenticated key agreement protocol is an important primitive for establishing session key to provide secure communications in open and distributed environment. Key escrow is essential in situations where confidentiality and audit trail are legal requirements, whilst perfect forward secrecy is desirable to provide stronger security. i.e. the adversary couldn´t acquire the past session keys even the long term key of user was compromised. In this paper, we present a secure two-party identity-based authenticated key agreement protocol, which was inspired on a new identity-based encryption scheme first proposed by Gentry (Eurocrypt´06). The new protocol achieves most of the required security attributes and can be used properly in the escrow mode. We show that the scheme achieves the attributes of known-key secrecy, key-compromise impersonation resilience, unknown key-share resilience and no key control. In addition, it captures the perfect forward secrecy attribute.