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Information Security

Certificateless key agreement in the standard model

Georg Lippold, Juan González Nieto

Published Jan 1, 2010• 7 citations
OpenAlex

Abstract

We show how to construct a certificateless key agreement protocol from the certificateless key encapsulation mechanism introduced by \\cite{lippold-ICISC_2009} in ICISC 2009 using the \\cite{DBLP:conf/acisp/BoydCNP08} protocol from ACISP 2008. We introduce the Canetti-Krawczyk (CK) model for certificateless cryptography, give security notions for Type I and Type II adversaries in the CK model, and highlight the differences to the existing e$^2$CK model discussed by \\cite{DBLP:conf/pairing/LippoldBN09}. The resulting CK model is more relaxed thus giving more power to the adversary than the original CK model.

Related papers

Key Agreement in the Standard Model

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We show how to construct a certicateless key agreement protocol from the certicateless key encapsulation mechanism introduced by Lippold et al. (2009a) in ICISC 2009 using the Boyd et al. (2008) protocol from ACISP 2008. We introduce the CanettiKrawczyk (CK) model for certicateless cryptography, give security notions for Type I and Type II adversaries in the CK model, and highlight the dierences to the existing e 2 CK model discussed by Lippold et al. (2009b). The resulting CK model is more relaxed thus giving more power to the adversary than the original CK model.

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Two new authenticated key agreement protocols in the certificateless setting are presented in this paper. Both are proved secure in the extended Canetti-Krawczyk model, under the BDH assumption. The first one is more efficient than the Lippold et al.'s (LBG) protocol, and is proved secure in the same security model. The second protocol is proved secure under the Swanson et al.'s security model, a weaker model. As far as we know, our second proposed protocol is the first one proved secure in the Swanson et al.'s security model. If no pre-computations are done, the first protocol is about 26% faster than LBG, and the second protocol is about 49% faster than LBG, and about 31% faster than the first one. If pre-computations of some operations are done, our two protocols remain faster.

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The main goal of cryptography is to enable secure communication over a public channel; often a secret shared among the communicating parties is used to achieve this. The process by which these parties agree on such a shared secret is called key agreement. In this thesis, we focus on two-party key agreement protocols in the public-key setting and study the various methods used to establish and validate public keys. We pay particular attention to certificateless key agreement schemes and attempt to formalize a relevant notion of security. To that end, we give a possible extension of the existing extended Canetti-Krawzcyk security model applicable to the certificateless setting. We observe that none of the certificateless protocols we have seen in the literature are secure in this model; it is an open question whether such schemes exist. We analyze several published certificateless key agreement protocols, demonstrating the existence of key compromise impersonation attacks and even a man-in-the-middle attack in one case, contrary to the claims of the authors. We also briefly describe weaknesses exhibited by these protocols in the context of our suggested security model.

•Dec 22, 2008•48 citations
We show how to construct a certificateless key agreement protocol from the certificateless key encapsulation mechanism introduced by \cite{lippold-ICISC_2009} in ICISC 2009 using the \cite{DBLP:conf/acisp/BoydCNP08} protocol from ACISP 2008. We introduce the Canetti-Krawczyk (CK) model for certificateless cryptography, give security notions for Type I and Type II adversaries in the CK model, and highlight the differences to the existing e2^22CK model discussed by \cite{DBLP:conf/pairing/LippoldBN09}. The resulting CK model is more relaxed thus giving more power to the adversary than the original CK model.
We show how to construct a certicateless key agreement protocol from the certicateless key encapsulation mechanism introduced by Lippold et al. (2009a) in ICISC 2009 using the Boyd et al. (2008) protocol from ACISP 2008. We introduce the CanettiKrawczyk (CK) model for certicateless cryptography, give security notions for Type I and Type II adversaries in the CK model, and highlight the dierences to the existing e 2 CK model discussed by Lippold et al. (2009b). The resulting CK model is more relaxed thus giving more power to the adversary than the original CK model.
In the area of network information security,key agreement is essential between servers and clients.To overcome the key escrow property of identity-based cryptography,proposed certificateless public key cryptography,it combined the advantages of the traditional PKI and the identity-based cryptography.This paper proposed a new certificateless two-party key agreement protocol using pairing operation in elliptic curves,it only required each party to compute one pairing.Proved its security in ECK(extended Canetti-Krawczyk) model.Compared with existing certificateless protocols,the newly proposed key agreement protocol has better security and efficiency.
Abstract. Recently, He et al. (Computers and Mathematics with Applications, 2012, 64(6): 1914-1926) proposed a new efficient certificateless two-party authenticated key agreement protocol. They claimed their protocol was provably secure in the extended Canetti-Krawczyk (eCK) model. In this paper, we will show that their protocol is insecure. A type I adversary, who obtains one party’s ephemeral private key, can impersonate the party to cheat the other party and compute the shared session key successfully. For overcoming this weakness, we also propose a simple countermeasure.
Certificateless cryptography aims at combining the advantages of identity based and public key cryptography in order to avoid the key escrow problem inherent in the identity based cryptography and cumbersome certificate management in the traditional public key infrastructure. The provably secure certificateless key agreement protocol is proposed by Lippold et al. in 2009, but their protocol suffers from computation burden. Owing to the above-mentioned situations, a new certificateless two party key agreement protocol (CL-KA) is proposed and the security attributes are analyzed in the extended Canetti-Krawzcyk(eCK) security model. Our protocol only requires each entity to compute two pairings, up to now, it turns out to be the most efficient one of all the previously known security CL-KA schemes.
Two new authenticated key agreement protocols in the certificateless setting are presented in this paper. Both are proved secure in the extended Canetti-Krawczyk model, under the BDH assumption. The first one is more efficient than the Lippold et al.'s (LBG) protocol, and is proved secure in the same security model. The second protocol is proved secure under the Swanson et al.'s security model, a weaker model. As far as we know, our second proposed protocol is the first one proved secure in the Swanson et al.'s security model. If no pre-computations are done, the first protocol is about 26% faster than LBG, and the second protocol is about 49% faster than LBG, and about 31% faster than the first one. If pre-computations of some operations are done, our two protocols remain faster.
The main goal of cryptography is to enable secure communication over a public channel; often a secret shared among the communicating parties is used to achieve this. The process by which these parties agree on such a shared secret is called key agreement. In this thesis, we focus on two-party key agreement protocols in the public-key setting and study the various methods used to establish and validate public keys. We pay particular attention to certificateless key agreement schemes and attempt to formalize a relevant notion of security. To that end, we give a possible extension of the existing extended Canetti-Krawzcyk security model applicable to the certificateless setting. We observe that none of the certificateless protocols we have seen in the literature are secure in this model; it is an open question whether such schemes exist. We analyze several published certificateless key agreement protocols, demonstrating the existence of key compromise impersonation attacks and even a man-in-the-middle attack in one case, contrary to the claims of the authors. We also briefly describe weaknesses exhibited by these protocols in the context of our suggested security model.