102 research outputs found
On the Relations Between Diffie-Hellman and ID-Based Key Agreement from Pairings
This paper studies the relationships between the traditional Diffie-Hellman
key agreement protocol and the identity-based (ID-based) key agreement protocol
from pairings.
For the Sakai-Ohgishi-Kasahara (SOK) ID-based key construction, we show that
identical to the Diffie-Hellman protocol, the SOK key agreement protocol also
has three variants, namely \emph{ephemeral}, \emph{semi-static} and
\emph{static} versions. Upon this, we build solid relations between
authenticated Diffie-Hellman (Auth-DH) protocols and ID-based authenticated key
agreement (IB-AK) protocols, whereby we present two \emph{substitution rules}
for this two types of protocols. The rules enable a conversion between the two
types of protocols. In particular, we obtain the \emph{real} ID-based version
of the well-known MQV (and HMQV) protocol.
Similarly, for the Sakai-Kasahara (SK) key construction, we show that the key
transport protocol underlining the SK ID-based encryption scheme (which we call
the "SK protocol") has its non-ID counterpart, namely the Hughes protocol.
Based on this observation, we establish relations between corresponding
ID-based and non-ID-based protocols. In particular, we propose a highly
enhanced version of the McCullagh-Barreto protocol
Obtaining a secure and efficient key agreement protocol from (H)MQV and NAXOS (extended version)
Updated (extended) and corrected version; see "Errata" and "Revisions" in the appendix for a summary of changes.LaMacchia, Lauter and Mityagin recently presented a strong security definition for authenticated key agreement strengthening the well-known Canetti-Krawczyk definition. They also described a protocol, called NAXOS, that enjoys a simple security proof in the new model. Compared to MQV and HMQV, NAXOS is less efficient and cannot be readily modified to obtain a one-pass protocol. On the other hand MQV does not have a security proof, and the HMQV security proof is extremely complicated.
This paper proposes a new authenticated key agreement protocol, called CMQV (`Combined' MQV), which incorporates design principles from MQV, HMQV and NAXOS. The new protocol achieves the efficiency of HMQV and admits a natural one-pass variant. Moreover, we present a simple and intuitive proof that CMQV is secure in the LaMacchia-Lauter-Mityagin model
Review on Leakage Resilient Key Exchange Security Model
In leakage resilient cryptography, leakage resilient key exchange protocols are constructed to defend against leakage attacks. Then, the key exchange protocol is proved with leakage resilient security model to determine whether its security proof can provide the security properties it claimed or to find out any unexamined flaw during protocol building. It is an interesting work to review the meaningful security properties provided by these security models. This work review how a leakage resilient security model for a key exchange protocol has been evolved over years according to the increasing security requirement which covers a different range of attacks. The relationship on how an adversary capability in the leakage resilient security model can be related to real-world attack scenarios is studied. The analysis work for each leakage resilient security model here enables a better knowledge on how an adversary query addresses different leakage attacks setting, thereby understand the motive of design for a cryptographic primitive in the security model
A Cryptographic Analysis of the WireGuard Protocol
WireGuard (Donenfeld, NDSS 2017) is a recently proposed secure network tunnel operating at layer 3. WireGuard aims to replace existing tunnelling solutions like IPsec and OpenVPN, while requiring less code, being more secure, more performant, and easier to use. The cryptographic design of WireGuard is based on the Noise framework. It makes use of a key exchange component which combines long-term and ephemeral Diffie-Hellman values (along with optional preshared keys). This is followed by the use of the established keys in an AEAD construction to encapsulate IP packets in UDP. To date, WireGuard has received no rigorous security analysis. In this paper, we, rectify this. We first observe that, in order to prevent Key Compromise Impersonation (KCI) attacks, any analysis of WireGuard\u27s key exchange component must take into account the first AEAD ciphertext from initiator to responder. This message effectively acts as a key confirmation and makes the key exchange component of WireGuard a 1.5 RTT protocol. However, the fact that this ciphertext is computed using the established session key rules out a proof of session key indistinguishability for WireGuard\u27s key exchange component, limiting the degree of modularity that is achievable when analysing the protocol\u27s security. To overcome this proof barrier, and as an alternative to performing a monolithic analysis of the entire WireGuard protocol, we add an extra message to the protocol. This is done in a minimally invasive way that does not increase the number of round trips needed by the overall WireGuard protocol. This change enables us to prove strong authentication and key indistinguishability properties for the key exchange component of WireGuard under standard cryptographic assumptions
Efficient key exchange with tight security reduction
In this paper, we propose two authenticated key exchange (AKE) protocols, SMEN and SMEN−, which have efficient online computation and tight security proof in the extended Canetti-Krawczyk (eCK) model. SMEN takes 1.25 exponentiations in online computation, close to that (1.17 exponentiations) of the most efficient AKEs MQV and its variants HMQV and CMQV. SMEN has a security reduction as tight as that of NAXOS, which is the first AKE having a tight security reduction in the eCK model. As a comparison, MQV does not have a security proof; both HMQV and CMQV have a highly non-tight security reduction, and HMQV needs a non-standard assumption; NAXOS takes 2.17 exponentiations in online computation; NETS, a NAXOS variant, takes two online exponentiations in online computation. SMEN simultaneously achieves online efficiency and a tight security proof at a cost of 0.17 more exponentiations in offline computation and the restriction that one party is not allowed to establish a key with itself. SMEN− takes 1.29 exponentiations in online computation, but SMEN− does not use the static private key to compute the ephemeral public key (as does in SMEN, NAXOS, CMQV, and NETS), and hence reduces the risk of leaking the static private key
Authenticated Key Exchange Protocols with Enhanced Freshness Properties
In this paper, we investigate the security model for authenticated
key exchange protocols. We observe that there is further room to
extend the latest enhanced Canetti-Krawczyk (eCK) model.
We further enhance the freshness definition for the three-pass
authenticated key exchange protocols such that our new definition
gives the adversary more capabilities. We point out that the
three-pass authenticated key exchange protocols generically transformed from the two-pass authenticated key exchange protocols secure in the eCK model can not be secure in our new
security definition. We then introduce a new authenticated key
exchange protocol SIG-DH and prove that it satisfies our new
definition
Authenticated Key Exchange Secure under the Computational Diffie-Hellman Assumption
In this paper, we present a new authenticated key exchange(AKE)
protocol and prove its security under the random oracle assumption
and the computational Diffie-Hellman(CDH) assumption. In the
extended Canetti-Krawczyk model, there has been no known AKE
protocol based on the CDH assumption. Our protocol, called NAXOS+,
is obtained by slightly modifying the NAXOS protocol proposed by
LaMacchia, Lauter and Mityagin. We establish a formal security proof
of NAXOS+ in the extended Canetti-Krawczyk model using as a main
tool the trapdoor test presented by Cash, Kiltz and Shoup
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