Nowadays many crucial network applications rely on the existence of a confidential channel established by authenticated key exchange (AKE) protocols over public networks.With the rapid development of cyber technology, novel attacks to cryptosystem emerge in an endless stream.This has also led to the development of AKE solutions to provide increasingly stronger security guarantees.In this thesis we focus on provision of practical constructions for AKE protocols which are provably secure in a strong sense without resorting to random oracles.We first we present three new efficient compilers to generically turn passively secure key exchange protocols (KE) into authenticated key exchange protocols (AKE) where security also holds in the presence of active adversaries.Our compilers are not only a useful tool for the design of new AKE systems with many additional security properties in a modular and less error-prone fashion, but they also help to relax the assumptions on existing, practical key exchange mechanisms which are not known to be provably secure AKE protocols.Security of our compilers is shown in a strong modified CK model where the adversary is allowed to reveal either long-term secret key or state information of the protocol participants.On the second, we study the open problem on constructing eCK secure two party AKE protocol without random oracles and NAXOS trick.A generic construction satisfying those requirements is given based on well-known cryptographic primitives following the guideline of efficiency.Then a concrete protocol is proposed which is the first eCK secure protocol in the standard model under both standard assumptions and post-specified peer setting (i.e.without knowing any cryptographic information about its communication peer).Both proposed schemes can be more efficiently implemented with secure device than previous works which are eCK secure in the standard model, where the secure device might be normally used to store the long-term private key and to implement codes of protocol which need to be resilience of state leakage.Finally, we generalize our one-round two party AKE construction to group case that yields an efficient tripartite AKE protocol based on bilinear maps and a candidate group AKE protocol (with more than three members) based on multilinear maps.Up to now they are the first solutions which can be proved secure in the g-eCK model without random oracles.Meanwhile we make first step to show how to simplify the security proof for one-round group AKE under g-eCK model.i
A two-party authenticated key exchange (AKE) protocol allows each of the two parties to share a common secret key over insecure channels, even in the presence of active adversaries who can actively control and modify the exchanged messages. To capture the malicious behaviors of the adversaries, there have been many efforts to define security models. Amongst them, the extended Canetti–Krawczyk (eCK) security model is considered one of the strongest security models and has been widely adopted. In this paper, we present a simple construction of a pairing-based eCK-secure AKE protocol in the standard model. Our protocol can be instantiated with a suitable signature scheme (i.e., an existentially unforgeable signature scheme against adaptive chosen message attacks). The underlying assumptions of our construction are the decisional bilinear Diffie–Hellman assumption and the existence of a pseudorandom function. Note that the previous eCK-secure protocol constructions either relied on random oracles for their security or used somewhat strong assumptions, such as the existence of strong-pseudorandom functions, target collision-resistant functions, etc., while our protocol construction uses fewer and more-standard assumptions in the standard model. Furthermore, preserving the same security argument, our protocol can be instantiated with any appropriate signature scheme that comes in the future with better efficiency.
The extended Canetti–Krawczyk (eCK) security models, are widely used to provide security arguments for authenticated key exchange protocols that capture leakage of various kinds of secret information like the long-term private key and session-specific secret state. In this paper, we study the open problem on constructing eCK secure AKE protocol without random oracles and NAXOS like trick. A generic construction GC-KKN satisfying those requirements is first given relying on standard cryptographic primitives following the guideline of efficiency. On the second a concrete protocol is proposed which is the first eCK secure protocol in the standard model under both standard assumptions and post-specified peer setting. Both proposed schemes can be more efficiently implemented with secure device than previous eCK secure protocols in the standard model, where the secure device might be normally used to store the long-term private key and implement algorithms of protocol which require to be resilience of state leakage.
Abstract. This paper investigates the two-pass authenticated key exchange protocol in the enhanced Canetti-Krawczyk (eCK) with perfect forward security. Currently, there exist no authenticated key exchange protocols which are provably secure in eCK model and meanwhile achieve perfect forward security against active adversary in one round. We propose a new two-pass authenticated key exchange protocol which enjoys following desirable properties. First, our protocol is shown secure in the eCK model under the gap Diffie-Hellman (GDH) assumption. Moreover, our protocol does not use the NAXOS transformation, the drawback of which will be discussed in the introduction. Second, under the same assumption, we prove that our protocol achieves perfect forward security against active adversary in one round. To the best of our knowledge, our proposal is first two-pass (one round) AKE protocol provably secure in the eCK model and achieving perfect forward security against active adversary.
Recently, LaMacchia, Lauter and Mityagin proposed the extended Canetti-Krawczyk (eCK) model for Authenticated Key Exchange (AKE) protocols that covers many attacks on existing models. An ID-based AKE protocol with Perfect Forward Secrecy (PFS) (respectively Master Perfect Forward Secrecy (MPFS)) ensures that revelation of the static keys of the parties (respectively the master secret key of the private key generator), must not compromise even a single bit of the session keys of the past sessions between the parties. Currently, to the best of our knowledge, there is no ID-based eCK secure single round AKE protocol with either PFS or MPFS. In our preliminary version [18] we have proposed, without proofs, ID-based eCK secure single round AKE protocols with PFS and MPFS in the random oracle model. To achieve this, we also have constructed ID-based eCK secure single round AKE protocols, one without Master Forward Secrecy (MFS) and one with MFS, almost at the same computational cost as the existing efficient ID-based eCK Secure Single Round AKE protocols. In this full version, we provide proofs to show that all of our protocols are secure under the Gap Bilinear Diffie-Hellman (GBDH) problem.