Off-line dictionary attack on password-based authenticated key exchange protocols

In smart grid, key exchange protocols play a vital role in providing secure channels to read consumption reports from the smart meters. Thus far, several key exchange schemes have been proposed for the networked smart meters. However, for the first time, quite recently, Sha et al . have presented an interesting two-phase authentication and key agreement scheme that exclusively aims at the isolated smart meters. In their scheme, they have properly addressed the computationally constrained smart meters by offering a lightweight key exchange protocol. Nevertheless, after meticulous observation, we found that their proposed scheme cannot resist the desynchronization attack and cannot provide the perfect forward secrecy. Moreover, there are some other weaknesses in their scheme. As a result, to tackle the existing security challenges, in this paper, by utilization of the extended Chebyshev chaotic maps, we propose an efficient anonymous password-authenticated key exchange protocol that not only is free from the limitations of Sha et al .'s scheme, but also provides the anonymity. The security analysis in the random oracle model and using the widely accepted ProVerif tool besides the computational and communication costs comparison demonstrate that the proposed scheme has reached a proper level of efficiency without sacrificing the desired security properties.

There have been many proposals in recent years for password-authenticated key exchange protocols.Man y of these have been shown to be insecure, and the only ones that seemed likely to be proven secure (against active adversaries who may attempt to perform off-line dictionary attacks against the password) were based on the Diffie-Hellman problem. In fact, some protocols based on Diffie-Hellman have been recently proven secure in the random-oracle model. We examine how to design a provably-secure password-authenticated key exchange protocol based on RSA.We first look at the OKE and protected-OKE protocols (both RSA-based) and show that they are insecure.Then we show how to modify the OKE protocol to obtain a password-authenticated key exchange protocol that can be proven secure (in the random oracle model). The resulting protocol is very practical; in fact the basic protocol requires about the same amount of computation as the Diffie-Hellman-based protocols or the well-known ssh protocol.

With the popularity of unmanned aerial vehicles (UAVs), more and more valuable data can be collected by UAVs. In order to balance the data usage and communication cost, the data can be preprocessed in UAVs rather than directly transmitting to the data centre in the edge computing paradigm. Users can obtain information of interest by accessing the data centre remotely by authenticating themselves to the data centre using the most pervasive password authentication method. Unfortunately, the data centre becomes the main attack target because it not only stores the data but also maintains the passwords of all the users. Aiming at protecting the data as well as the password in the UAV‐enabled mobile edge computing environment, the authors combine the advantages of gateway‐oriented password authenticated key exchange (PAKE) protocols and two‐server PAKE protocols and put forward an efficient gateway‐oriented two‐server PAKE protocol. The security of the proposed protocol is given in the random oracle model. The performance comparison shows their proposal has comparable efficiency in computation and communication costs. Their protocol provides better protection to the password without sacrificing efficiency. Consequently, their protocol is more suitable for real applications in UAV‐enabled mobile edge computing environment.

In recent years, attribute-based encryption (ABE) provides a new idea to help researchers solving the problem of data privacy protection in cloud. But there are two issues in traditional ABE, the first issue is that the attributes in the access structures will be sent to users in cleartext together with the ciphertext. So a attacker has the opportunity to obtain some of the private information from the plaintext access structure. And the other issue is the traditional ABE scheme cannot revoke the users' illegal keys in an efficient way. To handle both of the above challenges, we come up with a large universe ciphertext-policy ABE (CP-ABE) scheme which supports partially hidden access structures (PHAS) and highly efficient key revocation at the same time in this paper. What's more, unlike most previous schemes, first our access structure is based on the expressive linear secret sharing scheme (LSSS) which supports both AND and OR gates in access formulas and second our scheme is built from the prime-order bilinear pairing groups. The comparison with other relevant works presents that our scheme is more comprehensive and efficient. Finally we rigorously prove and analyze that our scheme is selectively indistinguishable secure under chosen plaintext attacks (IND-CPA) in the random oracle model (ROM) and our access structure is really anonymous against off-line dictionary attacks.

In recent years, many password authenticated key exchange (PAKE) protocols have been proposed. However, many of them have been broken or have no security proof. In this paper, we propose an efficient password authenticated key exchange protocol using bilinear pairings. Compared with previous PAKE protocol using bilinear pairings, our protocol is quite efficient both in communication cost and computational cost. Moreover, this paper proves that the novel protocol is forward secrecy under the Bilinear Diffie-Hellman (BDH) assumption in the random oracle model.KeywordsPAKEbilinear paringBDHforward secrecy

The main contribution of this paper is to analyze a secure passwordauthentication mechanism (SPAM), proposed by Chuang et al. in 2013(IEEE Syst J.). The SPAM was used for designing a secure handover inProxy Mobile IPv6 (PMIPv6) networks. Chuang et al. in the originalpaper claimed that SPAM provides high security properties and canresist various attacks. However, in this paper we point out thatSPAM is vulnerable to the critical attacks, such as stolen smartcard and off-line dictionary attack, replay attack and impersonationattack. In addition, we show that the identity of MNs and thesession key between MN and MAG can be disclosed by an insiderattacker; resultantly, anonymity and confidentiality between MNs andMAG will be completely broken in SPAM. As a remedy, we also propose an improved scheme which not only conquers the problems of the previous schemes but also provides a reduction in computational cost. Moreover, the proposed scheme provides the user anonymity and untraceability and secure session key agreement. Finally, the security of the improved protocol is proved in the random oracle model.DOI: http://dx.doi.org/10.5755/j01.itc.46.2.12118

This paper introduces a new scheme, called Augmented Password AKE (APAKE), for authenticated key exchange protocols. In APAKE, a password is represented by a pair of values that is randomly selected in a huge space.We present an APAKE protocol. The protocol is secure against the attacks including offline dictionary attack and server compromise allowing for subsequent off-line dictionary attack. The protocol has a pass number of two, and it requires minor computational amounts. We also present a EKE protocol de-signed by simple modification of the APAKE protocol while preserving the security of the APAKE protocol.KeywordsHash FunctionPast CommunicationDictionary AttackCryptographic FunctionInteger Factorization ProblemThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Security issues play an important role in modern communication worlds. Via distrusted networks, exchanged messages need to be encrypted by a session key for security requirements. Session keys are preferred to be generated by communication parties, and how to authenticate the other communication party is an important problem needed to be solved. In three-party encrypted key exchange (3PEKE) protocols, a special type of indirect-authenticated protocols, a trusted third party is involved to have two communication parties be able to authenticate each other and negotiate one session key. In 2008, Yoon and Yoo proposed a three-party encrypted key exchange protocol and claimed their protocol provides a more secure way for exchanging messages. Unfortunately, we find that their protocol suffers from undetectable one-line password guessing attacks. In this manuscript, we first review the important related works and show how to mount attacks on Yoon and Yoo’s 3PEKE protocol

A password-authenticated key exchange (PAKE) protocol allows two entities sharing a password to perform mutual authentication and establish a session key. Benefiting from the use of a low-entropy human-memorable password, PAKE avoids the use of PKI in the authentication process, making it more flexible and cheaper. However, with the development of quantum computing, protocols based on classical assumptions will no longer be secure, so designing a PAKE protocol capable of resisting quantum attacks has become an important research direction. In this work, we propose an efficient PAKE protocol using a new error reconciliation mechanism based on the ring learning with errors (RLWE) problem, which is considered to resist quantum attacks. Our protocol is proven security under the Bellare-Pointcheval-Rogaway (BPR) model. The protocol is implemented using the C language, which is highly portable, and is also optimized utilizing the Advanced Vector Extensions 2 (AVX2) instruction set. Compared with the C implementation of Ding’s protocol, our reference C implementation is more than 12x faster, and the efficiency is doubled after AVX2 optimization. Moreover, by choosing the appropriate parameters, the security strength of our scheme is improved and the message size is reduced.

Security proof is a key criterion to judge the satisfaction of the security requirements in a protocol. Recently, Chang et al. proposed a password-based three-party key exchange protocol without server's public key. The security goal of the proposed protocol is to eliminate various security threats. In this paper, we show that the proposed protocol is still suffered from the denial of service and the man-in-the-middle attacks. We also prove that the probability of an adversary breaking the AKE security of the protocol is non-negligible in the random oracle model.

With the great development of network technology, the multiserver system gets widely used in providing various of services. And the two-factor authentication protocols in multiserver system attract more and more attention. Recently, there are two new schemes for multiserver environment which claimed to be secure against the known attacks. However, after a scrutinization of these two schemes, we found that (1) their description of the adversary’s abilities is inaccurate; (2) their schemes suffer from many attacks. Thus, firstly, we corrected their description on the adversary capacities to introduce a widely accepted adversary model and then summarized fourteen security requirements of multiserver based on the works of pioneer contributors. Secondly, we revealed that one of the two schemes fails to preserve forward secrecy and user anonymity and cannot resist stolen-verifier attack and off-line dictionary attack and so forth and also demonstrated that another scheme fails to preserve forward secrecy and user anonymity and is not secure to insider attack and off-line dictionary attack, and so forth. Finally, we designed an enhanced scheme to overcome these identified weaknesses, proved its security via BAN logic and heuristic analysis, and then compared it with other relevant schemes. The comparison results showed the superiority of our scheme.

Cryptographic Primitives that Resist Backdooring and Subversion

We revisit the problem of protecting user's private data against adversarial compromise of user's device(s) which store this data. We formalize the solution we propose as Password-Protected Secret-Sharing (PPSS), which allows a user to secret-share her data among n trustees in such a way that (1) the user can retrieve the shared secret upon entering a correct password into a reconstruction protocol, which succeeds as long as at least t+1 uncorrupted trustees are accessible, and (2) the shared data remains secret even if the adversary which corrupts t trustees, with the level of protection expected of password-authentication, i.e. the probability that the adversary learns anything useful about the secret is at most q/|D| where q is the number of reconstruction protocol the adversary manages to trigger and |D| is the size of the password dictionary. We propose an efficient PPSS protocol in the PKI model, secure under the DDH assumption, using non-interactive zero-knowledge proofs with efficient instantiations in the Random Oracle Model. Our protocol is practical, with fewer than 16 exponentiations per trustee and 8t+17 exponentiations per user, with O(1) bandwidth between the user and each trustee, and only three message flows, implying a single round of interaction in the on-line phase. As a side benefit our PPSS protocol yields a new Threshold Password Authenticated Key Exchange (T-PAKE) protocol in the PKI model with significantly lower message, communication, and server computation complexities then existing T-PAKE's.

Both mutual authentication and generation of session keys can be accomplished by an authenticated key exchange (AKE) protocol. Let us consider the following situation: (1) a client, who communicates with many different servers, remembers only one password and has insecure devices (e.g., mobile phones or PDAs) with very-restricted computing power and built-in memory capacity; (2) the counterpart servers have enormous computing power, but they are not perfectly secure against various attacks (e.g., virus or hackers); (3) neither PKI (Public Key Infrastructures) nor TRM (Tamper-Resistant Modules) is available. The main goal of this paper is to provide security against the leakage of stored secrets as well as to attain high efficiency on client's side. For those, we propose an efficient and leakage-resilient RSA-based AKE (RSA-AKE) protocol suitable for the above situation whose authenticity is based on password and another secret. In the extended model where an adversary is given access to the stored secret of client, we prove that its security of the RSA-AKE protocol is reduced tightly to the RSA one-wayness in the random oracle model. We also show that the RSA-AKE protocol guarantees several security properties (e.g., security of password, multiple sever scenario with only one password, perfect forward secrecy and anonymity). To our best knowledge, the RSA-AKE protocol is the most efficient, in terms of both computation costs of client and communication costs, over the previous AKE protocols of their kind (using password and RSA).

Password-authenticated key exchange (PAKE) protocols tackle the important problem of how to enable two parties, who share a low-entropy password, to establish a cryptographically strong session key for secure data communication. Although considerable research efforts have been devoted to designing hundreds of PAKE protocols, to the best of our knowledge, there have been few systematic reviews. In this work, we provide a comprehensive overview of PAKE research. We first propose a list of 13 desirable properties of PAKE protocols in terms of security and usability, enabling PAKE protocols to be systematically rated across a common spectrum. We then provide a taxonomy for PAKE protocols, and classify them into seven types according to their underlying design strategies. For each type, we investigate the inner working mechanisms of various representative protocols, and identify their pros, and cons. We further classify existing PAKE protocols from five other key perspectives (i.e., symmetry, number of participants, hardness assumptions, security goals, and round complexity) and review their development history under each classification, aiming to provide an in-depth and thorough understanding of the status quo of PAKE research. Based on 13 properties and six perspectives, we conduct a large-scale comparative evaluation of 71 representative PAKE protocols in a systematic manner. Finally, we highlight a few potential directions for the future design of PAKE protocols.