Strongly secure ID‐based authenticated key agreement protocol for mobile multi‐server environments

To provide mutual authentication and communication confidentiality between mobile clients and servers, numerous identity‐based authenticated key agreement (ID‐AKA) protocols were proposed to authenticate each other while constructing a common session key. In most of the existing ID‐AKA protocols, ephemeral secrets (random values) are involved in the computations of the common session key between mobile client and server. Thus, these ID‐AKA protocols might become vulnerable because of the ephemeral‐secret‐leakage (ESL) attacks in the sense that if the involved ephemeral secrets are compromised, an adversary could compute session keys and reveal the private keys of participants in an AKA protocol. Very recently, 2 ID‐AKA protocols were proposed to withstand the ESL attacks. One of them is suitable for single server environment and requires no pairing operations on the mobile client side. The other one fits multi‐server environments, but requires 2 expensive pairing operations. In this article, we present a strongly secure ID‐AKA protocol resisting ESL attacks under mobile multi‐server environments. By performance analysis and comparisons, we demonstrate that our protocol requires the lowest communication overhead, does not require any pairing operations, and is well suitable for mobile devices with limited computing capability. For security analysis, our protocol is provably secure under the computational Diffie‐Hellman assumption in the random oracle model.     

A pairing-free identity-based authenticated group key agreement protocol for imbalanced mobile networks

The secure and reliable group communication gains popularity in imbalanced mobile networks due to the increase demand of the group-oriented applications such as teleconferences, collaborative workspaces, etc. For acquiring the group security objectives, many authenticated group key agreement (AGKA) protocols exploiting the public key infrastructure have been proposed, which require additional processing and storage space for validation of the public keys and the certificates. In addition, the most of the AGKA protocols are implemented using bilinear pairing and a map-to-point (MTP) hash function. The relative computation cost of the bilinear pairing is approximately two to three times more than the elliptic curve point multiplication (ECPM) and the MTP function has higher computation cost than an ECPM. Due to the limitation of communication bandwidth, computation ability, and storage space of the low-power mobile devices, these protocols are not suitable especially for insecure imbalanced mobile networks. To cope with the aforementioned problems, in this paper, we proposed a pairing-free identity-based authenticated group key agreement protocol using elliptic curve cryptosystem. It is found that the proposed protocol, compared with the related protocols, not only improves the computational efficiencies, but also enhances the security features.     

Analysis and improvement of a new authenticated group key agreement in a mobile environment

In 2009, Lee et al. (Ann Telecommun 64:735–744, 2009) proposed a new authenticated group key agreement protocol for imbalanced wireless networks. Their protocol based on bilinear pairing was proven the security under computational Diffie–Hellman assumption. It remedies the security weakness of Tseng’s nonauthenticated protocol that cannot ensure the validity of the transmitted messages. In this paper, the authors will show that Lee et al.’s authenticated protocol also is insecure. An adversary can impersonate any mobile users to cheat the powerful node. Furthermore, the authors propose an improvement of Lee et al.’s protocol and prove its security in the Manulis et al.’s model. The new protocol can provide mutual authentication and resist ephemeral key compromise attack via binding user’s static private key and ephemeral key.     

Cryptanalysis of smart‐card‐based password authenticated key agreement protocol for session initiation protocol of Zhang et al.

As the core signaling protocol for multimedia services, such as voice over internet protocol, the session initiation protocol (SIP) is receiving much attention and its security is becoming increasingly important. It is critical to develop a roust user authentication protocol for SIP. The original authentication protocol is not strong enough to provide acceptable security level, and a number of authentication protocols have been proposed to strengthen the security. Recently, Zhang et al. proposed an efficient and flexible smart‐card‐based password authenticated key agreement protocol for SIP. They claimed that the protocol enjoys many unique properties and can withstand various attacks. However, we demonstrate that the scheme by Zhang et al. is insecure against the malicious insider impersonation attack. Specifically, a malicious user can impersonate other users registered with the same server. We also proposed an effective fix to remedy the flaw, which remedies the security flaw without sacrificing the efficiency. The lesson learned is that the authenticators must be closely coupled with the identity, and we should prevent the identity from being separated from the authenticators in the future design of two‐factor authentication protocols. Copyright © 2014 John Wiley & Sons, Ltd.     

A secure and efficient password‐authenticated group key exchange protocol for mobile ad hoc networks

Password‐authenticated group key exchange protocols enable communication parties to establish a common secret key (a session key) by only using short secret passwords. Such protocols have been receiving significant attention. This paper shows some security weaknesses in some recently proposed password‐authenticated group key exchange protocols. Furthermore, a secure and efficient password‐authenticated group key exchange protocol in mobile ad hoc networks is proposed. It only requires constant round to generate a group session key under the dynamic scenario. In other words, the overhead of key generation is independent of the size of a total group. Further, the security properties of our protocol are formally validated by a model checking tool called AVISPA. Security and performance analyses show that, compared with other related group key exchange schemes, the proposed protocol is also efficient for real‐world applications in enhancing the security over wireless communications. Copyright © 2011 John Wiley & Sons, Ltd.     

A chaotic map‐based anonymous multi‐server authenticated key agreement protocol using smart card

Authenticated key agreement protocols play an important role for network‐connected servers to authenticate remote users in Internet environment. In recent years, several authenticated key agreement protocols for single‐server environment have been developed based on chaotic maps. In modern societies, people usually have to access multiple websites or enterprise servers to accomplish their daily personal matters or duties on work; therefore, how to increase user's convenience by offering multi‐server authentication protocol becomes a practical research topic. In this study, a novel chaotic map‐based anonymous multi‐server authenticated key agreement protocol using smart card is proposed. In this protocol, a legal user can access multiple servers using only a single secret key obtained from a trusted third party, known as the registration center. Security analysis shows this protocol is secure against well‐known attacks. In addition, protocol efficiency analysis is conducted by comparing the proposed protocol with two recently proposed schemes in terms of computational cost during one authentication session. We have shown that the proposed protocol is twice faster than the one proposed by Khan and He while preserving the same security properties as their protocol has. Copyright © 2014 John Wiley & Sons, Ltd.     

Cryptanalysis and Enhancement of an Anonymous Self-Certified Key Exchange Protocol

Authentication protocols with anonymity have gained much popularity recently which allows users to access any public network without compromising their identity. Several key exchange protocols have been proposed in the literature using either public key infrastructure or identity-based cryptosystem. However, the former suffers from heavy computation cost and latter fails to prevent key escrow problem. Recently, Islam et al. have proposed a self-certified authenticated key agreement protocol based on ECC which removes the above limitations. However, through careful analysis, we found that their scheme lack anonymity and vulnerable to trace the attack, clogging attack, and fails to prevent the replay attack. To overcome these weaknesses, we propose an anonymous self-certified authenticated key exchange protocol by including the required security features. The scheme is formally proved using Automated Validation of Internet Security protocols and Applications software. Also, the formal authentication proofs using Burrows–Abadi–Needham logic ensures successful authentication. Furthermore, the performance analysis demonstrates that the proposed scheme accomplishes less computational cost and is applicable to a client–server architecture.     

A fault‐tolerant group key agreement protocol exploiting dynamic setting

A fault‐tolerant group key agreement is an essential infrastructure for Internet communication among all involved participants; it can establish a secure session key no matter how many malicious participants exit simultaneously in an effort to disrupt the key agreement process. Recently, Zhao et al. proposed an efficient fault‐tolerant group key agreement protocol named efficient group key agreement that can resist denial‐of‐service attacks, reply attacks, man‐in‐middle attacks, and common modulus attacks; it can also preserve forward secrecy with lower computational cost than previous protocols. We show that it is still vulnerable to active attacks by malicious participants and modify the corresponding security weakness adaptively. Furthermore, we propose an efficient fault‐tolerant group key agreement based on a binary tree structure and enhance it to a dynamic setting where participants can leave or join the group arbitrarily according to their preferences with instant session key refreshment. Additionally, our session key refreshment is based on secure key updating to protect forward/backward confidentiality and is resistant to active/passive attacks. The performance analysis shows that our proposed protocol has lower computational cost and little additional communication cost exploiting dynamic setting. Copyright © 2013 John Wiley & Sons, Ltd.     

On the security and improvement of privacy‐preserving 3‐factor authentication scheme for TMIS

The telecare medicine information system (TMIS) enables patients from different regions to remotely share the same telecare services, which significantly enhances the quality and effectiveness of medical treatment. On the other hand, patients' electronic health records usually involve their privacy information, they thus hesitate to directly transmit these information in TMIS over the public network due to the threat of privacy disclosure. The authenticated key agreement, as a core building of securing communications over the public network, is considered to be necessary for strengthening the security of TMIS. Recently, we note Zhang et al introduced a 3‐factor authenticated key agreement scheme for TMIS and asserted that the proposed scheme can resist various well‐known attacks. Unfortunately, in this paper, we point out that the scheme of Zhang et al cannot achieve the claimed security guarantees. Specifically, their scheme is vulnerable to offline password/identity guessing attack and user/server impersonation attack. To conquer the above security pitfalls, we put forward a new 3‐factor authenticated key agreement scheme with privacy preservation for TMIS. The security evaluation and performance discussion indicate that our scheme can be free from those well‐known and classical attacks including offline guessing attack and impersonation attack, without increasing additional computation cost when compared with related works. Consequently, the new authentication scheme would be more desirable for securing communications in TMIS.     

Improvement of robust smart‐card‐based password authentication scheme

Smart‐card‐based password authentication scheme is one of the commonly used mechanisms to prevent unauthorized service and resource access and to remove the potential security threats over the insecure networks and has been investigated extensively in the last decade. Recently, Chen et al. proposed a smart‐card‐based password authentication scheme and claimed that the scheme can withstand offline password guessing attacks even if the information stored in the smart card is extracted by the adversary. However, we observe that the scheme of Chen et al. is insecure against offline password guessing attacks in this case. To remedy this security problem, we propose an improved authentication protocol, which inherits the merits of the scheme of Chen et al. and is free from the security flaw of their scheme. Compared with the previous schemes, our improved scheme provides more security guarantees while keeping efficiency. Copyright © 2013 John Wiley & Sons, Ltd.     

A new authenticated group key agreement in a mobile environment

A group key agreement protocol enables a group of communicating parties over an untrusted, open network to come up with a common secret key. It is designed to achieve secure group communication, which is an important research issue for mobile communication. In 2007, Tseng proposed a new group key agreement protocol to achieve secure group communication for a mobile environment. Its security is based on the decisional Diffie–Hellman assumption. It remedies the security weakness of the protocol of Nam et al. in which participants cannot confirm that their contributions were actually involved in the group key. Unfortunately, Tseng’s protocol is a nonauthenticated protocol that cannot ensure the validity of the transmitted messages. In this paper, the authors shall propose a new authenticated group key agreement to remedy it. It is based on bilinear pairings. We shall prove the security of the proposed protocol under the bilinear computational Diffie–Hellman assumption. It is also proven to a contributory group key agreement protocol.     

An efficient chaos‐based 2‐party key agreement protocol with provable security

Key agreement protocol is an important cryptographic primitive, which allows 2 parties to establish a secure session in an open network environment. A various of key agreement protocols were proposed. Nowadays, there still exists some other security flaws waiting to be solved. Owing to reduce the computational and communication costs and improve the security, chaotic map has been studied in‐depth and treated as a good solution. Recently, Liu et al proposed a chaos‐based 2‐party key agreement protocol and demonstrated that it can defend denial‐of‐service attack and replay attack. We found, however, it cannot resist off‐line password‐guessing attack, and it also has some other security flaws. In this paper, we propose an improved chaos‐based 2‐party key agreement protocol. The results prove that the protocol can solve the threats of off‐line password‐guessing attack and other security flaws in the security proof section. What is more, performance analysis shows that the computational cost of the improved protocol is lower than Liu et al protocol.     

Cryptanalysis of an identity‐based authenticated key exchange protocol

Authenticated key exchange protocols represent an important cryptographic mechanism that enables several parties to communicate securely over an open network. Elashry, Mu, and Susilo proposed an identity‐based authenticated key exchange (IBAKE) protocol where different parties establish secure communication by means of their public identities.The authors also introduced a new security notion for IBAKE protocols called resiliency, that is, if the secret shared key is compromised, the entities can generate another shared secret key without establishing a new session between them. They then claimed that their IBAKE protocol satisfies this security notion. We analyze the security of their protocol and prove that it has a major security flaw, which renders it insecure against an impersonation attack. We also disprove the resiliency property of their scheme by proposing an attack where an adversary can compute any shared secret key if just one secret bit is leaked.     

基于身份的认证密钥协商协议

密钥协商协议应该在满足安全性的条件下,使实现协议所需的计算开销尽可能小。文中提出了一个基于身份的认证密钥协商协议BAKAP(ID-Based Authenticated Key Agreement Protocol)。该协议提供了已知密钥安全性、完善前向保密性、密钥泄露安全性、未知密钥共享安全性和密钥控制安全性。在该协议中,参与者只需执行两次椭圆曲线点乘法和一次双线性运算。该协议与已有协议相比,计算代价小。     

Efficient authenticated key agreement protocols resistant to a denial‐of‐service attack

Malicious intruders may launch as many invalid requests as possible without establishing a server connection to bring server service to a standstill. This is called a denial‐of‐service (DoS) or distributed DoS (DDoS) attack. Until now, there has been no complete solution to resisting a DoS/DDoS attack. Therefore, it is an important network security issue to reduce the impact of a DoS/DDoS attack. A resource‐exhaustion attack on a server is one kind of denial‐of‐service attack. In this article we address the resource‐exhaustion problem in authentication and key agreement protocols. The resource‐exhaustion attack consists of both the CPU‐exhaustion attack and the storage‐exhaustion attack. In 2001, Hirose and Matsuura proposed an authenticated key agreement protocol (AKAP) that was the first protocol simultaneously resistant to both the CPU‐exhaustion attack and the storage‐exhaustion attack. However, their protocol is time‐consuming for legal users in order to withstand the DoS attack. Therefore, in this paper, we propose a slight modification to the Hirose–Matsuura protocol to reduce the computation cost. Both the Hirose–Matsuura and the modified protocols provide implicit key confirmation. Also, we propose another authenticated key agreement protocol with explicit key confirmation. The new protocol requires less computation cost. Because DoS/DDoS attacks come in a variety of forms, the proposed protocols cannot fully disallow a DoS/DDoS attack. However, they reduce the effect of such an attack and thus make it more difficult for the attack to succeed. Copyright © 2005 John Wiley & Sons, Ltd.     

A new authenticated key agreement for session initiation protocol

The session initiation protocol (SIP) is an authentication protocol used in 3G mobile networks. In 2009, Tsai proposed an authenticated key agreement scheme as an enhancement to SIP. Yoon et al. later pointed out that the scheme of Tsai is vulnerable to off‐line password guessing attack, Denning–Sacco attack, and stolen‐verifier attack and does not support perfect forward secrecy (PFS). Yoon et al. further proposed a new scheme with PFS. In this paper, we show that the scheme of Yoon et al. is still vulnerable to stolen‐verifier attack and may also suffer from off‐line password guessing attack. We then propose several countermeasures for solving these problems. In addition, we propose a new security‐enhanced authentication scheme for SIP. Our scheme also maintains low computational complexity. Copyright © 2011 John Wiley & Sons, Ltd.     

Cryptanalysis and improvement of a three‐party password‐based authenticated key exchange protocol with user anonymity using extended chaotic maps

Three‐party password‐authenticated key exchange (3PAKE) protocols allow two clients to agree on a secret session key through a server via a public channel. 3PAKE protocols have been designed using different arithmetic aspects including chaotic maps. Recently, Lee et al. proposed a 3PAKE protocol using Chebyshev chaotic maps and claimed that their protocol has low computation and communication cost and can also resist against numerous attacks. However, this paper shows that in spite of the computation and communication efficiency of the Lee et al. protocol, it is not secure against the modification attack. To conquer this security weakness, we propose a simple countermeasure, which maintains the computation and communication efficiency of the Lee et al. protocol. Copyright © 2014 John Wiley & Sons, Ltd.     

An efficient two‐party authentication key exchange protocol for mobile environment

The primary goal of this research is to ensure secure communications by client‐server architectures in mobile environment. Although various two‐party authentication key exchange protocols are proposed and claimed to be resistant to a variety of attacks, studies have shown that various loopholes exist in these protocols. What's more, many two‐party authentication key exchange protocols use timestamp to prevent the replay attack and transmit the user's identity in plaintext form. Obviously, these methods will lead to the clock synchronization problem and user's anonymity problem. Fortunately, the three‐way challenged‐response handshake technique and masking user's original identity with a secret hash value used in our study address these problems well. Of course, the proposed protocol based on elliptic curve cryptography supports flawless mutual authentication of participants, agreement of session key, impersonation attack resistance, replay attack resistance, and prefect forward secrecy, as well. The analyses in the aspects of efficiency and security show that the proposed protocol is a better choice for mobile users.     

A pairing‐free identity‐based handover AKE protocol with anonymity in the heterogeneous wireless networks

Nowadays, seamless roaming service in heterogeneous wireless networks attracts more and more attention. When a mobile user roams into a foreign domain, the process of secure handover authentication and key exchange (AKE) plays an important role to verify the authenticity and establish a secure communication between the user and the access point. Meanwhile, to prevent the user's current location and moving history information from being tracked, privacy preservation should be also considered. However, existing handover AKE schemes have more or less defects in security aspects or efficiency. In this paper, a secure pairing‐free identity‐based handover AKE protocol with privacy preservation is proposed. In our scheme, users' temporary identities will be used to conceal their real identities during the handover process, and the foreign server can verify the legitimacy of the user with the home server's assistance. Besides, to resist ephemeral private key leakage attack, the session key is generated from the static private keys and the ephemeral private keys together. Security analysis shows that our protocol is provably secure in extended Canetti‐Krawczyk (eCK) model under the computational Diffie‐Hellman (CDH) assumption and can capture desirable security properties including key‐compromise impersonation resistance, ephemeral secrets reveal resistance, strong anonymity, etc. Furthermore, the efficiency of our identity‐based protocol is improved by removing pairings, which not only simplifies the complex management of public key infrastructure (PKI) but also reduces the computation overhead of ID‐based cryptosystem with pairings. It is shown that our proposed handover AKE protocol provides better security assurance and higher computational efficiency for roaming authentication in heterogeneous wireless networks.     

SRGH: A secure and robust group‐based handover AKA protocol for MTC in LTE‐A networks

Machine‐type communication (MTC) is defined as an automatic aggregation, processing, and exchange of information among intelligent devices without humans intervention. With the development of immense embedded devices, MTC is emerging as the leading communication technology for a wide range of applications and services in the Internet of Things (IoT). For achieving the reliability and to fulfill the security requirements of IoT‐based applications, researchers have proposed some group‐based handover authentication and key agreement (AKA) protocols for mass MTCDs in LTE‐A networks. However, the realization of secure handover authentication for the group of MTCDs in IoT enabled LTE‐A network is an imminent issue. Whenever mass MTCDs enter into the coverage area of target base‐station simultaneously, the protocols incur high signaling congestion. In addition, the existing group‐based handover protocols suffer from the huge network overhead and numerous identified problems such as lack of key forward/backward secrecy, privacy‐preservation. Moreover, the protocols fail to avoid the key escrow problem and vulnerable to malicious attacks. To overcome these issues, we propose a secure and robust group‐based handover (SRGH) AKA protocol for mass MTCDs in LTE‐A network. The protocol establishes the group key update mechanism with forward/backward secrecy. The formal security proof demonstrates that the protocol achieves all the security properties including session key secrecy and data integrity. Furthermore, the formal verification using the AVISPA tool shows the correctness and informal analysis discusses the resistance from various security problems. The performance evaluation illustrates that the proposed protocol obtains substantial efficiency compared with the existing group‐based handover AKA protocols.