Abstract Password-based authenticated key exchange (PAKE) allows two parties to compute a common secret key. PAKE offers the advantage of allowing two parties to pre-share only a password. However, when it is executed in a client–server environment, server corruption can expose the clients’ passwords. To be resilient against server compromises, verifier-based authenticated key exchange (VPAKE) is proposed, as an augmented version of PAKE. Thus far, there are two known major VPAKE constructions formally proven secure. However, both involve strong assumptions, such as random oracles. In this paper, we propose a simple and efficient VPAKE using tamper-proof hardware without random oracles to support resilient infrastructures. In particular, we transform Katz–Vaikuntanathan one-round PAKE into two-round VPAKE so as to instill resilience to server compromises. We provide a formal definition of VPAKE using tamper-proof hardware and security proof without random oracles. Finally, we provide a performance analysis and comparisons to previous VPAKE and PAKE protocols. Our transformation supports an efficient VPAKE protocol with six group element communications when the underlying Katz–Vaikuntanathan PAKE is instantiated by Cramer–Shoup ciphertext following the proposal by Benhamouda et al.

Biometric Cryptosystems for secret binding such as fuzzy vault and fuzzy commitment are provable secure and offers a convenient way for secret management and protection. Despite numerous practical schemes have been reported, they are deficient in resisting several security and privacy attacks. In this paper, we propose a novel bio-cryptosystem that based on the three key ingredients namely Index of Maximum (IoM) hashing, (m, k) threshold secret sharing and b-band mini vaults notion. The IoM hashing is motivated from the ranking based Locality Sensitive Hashing theory meant for non-invertible transformation. On the other hand, the (m, k) threshold secret sharing scheme and the b-band mini vaults manage overcome inherent limitations of biometric cryptosystems when integrated with IoM hashing. The proposed scheme strikes the balance between performance and the privacy/security protection. Unlike fuzzy vault and fuzzy commitment, which primarily devised for unordered and binary biometrics, respectively, our scheme is tailored for feature vector-based biometrics (vectorial biometrics). Comprehensive experiments on fingerprint vectors that derived from several FVC fingerprint benchmarks and rigorous analysis demonstrate decent secret retrieval performance yet offer strong resilience against six major security and privacy attacks.

Biometric cryptosystems such as fuzzy vaults represent one of the most popular approaches for secret and biometric template protection. However, they are solely designed for biometric verification, where the user is required to input both identity credentials and biometrics. Several practical questions related to the implementation of biometric cryptosystems remain open, especially in regard to biometric template protection. In this article, we propose a face cryptosystem for identification (FCI) in which only biometric input is needed. Our FCI is composed of a one-to-N search subsystem for template protection and a one-to-one match chaff-less fuzzy vault (CFV) subsystem for secret protection. The first subsystem stores N facial features, which are protected by index-of-maximum (IoM) hashing, enhanced by a fusion module for search accuracy. When a face image of the user is presented, the subsystem returns the top k matching scores and activates the corresponding vaults in the CFV subsystem. Then, one-to-one matching is applied to the k vaults based on the probe face, and the identifier or secret associated with the user is retrieved from the correct matched vault. We demonstrate that coupling between the IoM hashing and the CFV resolves several practical issues related to fuzzy vault schemes. The FCI system is evaluated on three large-scale public unconstrained face datasets (LFW, VGG2, and IJB-C) in terms of its accuracy, computation cost, template protection criteria, and security.

Personal Identification Numbers (PINs) and pattern drawing have been used as common authentication methods especially on smartphones. Such methods, however, are very vulnerable to the shoulder surfing attack. Thus, keystroke dynamics that authenticate legitimate users based on their typing manner have been studied for years. However, many of the studies have focused on PC keyboard keystrokes. More studies on mobile and smartphones keystroke dynamics are warranted; as smartphones make progress in both hardware and software, features from smartphones have been diversified. In this paper, using various features including keystroke data such as time interval and motion data such as accelerometers and rotation values, we evaluate features with motion data and without motion data. We also compare 5 formulas for motion data, respectively. We also demonstrate that opposite gender match between a legitimate user and impostors has influence on authenticating by our experiment results.

Biometric data is user-identifiable and therefore methods to use biometrics for authentication have been widely researched. Biometric cryptosystems allow for a user to derive a cryptographic key from noisy biometric data and perform a cryptographic task for authentication or encryption. The fuzzy extractor is known as a prominent biometric cryptosystem. However, the fuzzy extractor has a drawback in that a user is required to store user-specific helper data or receive it online from the server with additional trusted channel, to derive a correct key. In this paper, we present a new biometric-based key derivation function (BB-KDF) to address the issues. In our BB-KDF, users are able to derive cryptographic keys solely from their own biometric data: users do not need any other user-specific helper information. We introduce a security model for the BB-KDF. We then construct the BB-KDF and prove its security in our security model. We then propose an authentication protocol based on the BB-KDF. Finally, we give experimental results to analyze the performance of the BB-KDF. We show that our proposed BB-KDF is computationally efficient and can be deployed on many different kinds of devices.

In this paper, we propose a ranking-based locality sensitive hashing inspired two-factor cancelable biometrics, dubbed “Index-of-Max” (IoM) hashing for biometric template protection. With externally generated random parameters, IoM hashing transforms a real-valued biometric feature vector into discrete index (max ranked) hashed code. We demonstrate two realizations from IoM hashing notion, namely, Gaussian random projection-based and uniformly random permutation-based hashing schemes. The discrete indices representation nature of IoM hashed codes enjoys several merits. First, IoM hashing empowers strong concealment to the biometric information. This contributes to the solid ground of non-invertibility guarantee. Second, IoM hashing is insensitive to the features magnitude, hence is more robust against biometric features variation. Third, the magnitude-independence trait of IoM hashing makes the hash codes being scale-invariant, which is critical for matching and feature alignment. The experimental results demonstrate favorable accuracy performance on benchmark FVC2002 and FVC2004 fingerprint databases. The analyses justify its resilience to the existing and newly introduced security and privacy attacks as well as satisfy the revocability and unlinkability criteria of cancelable biometrics.

Abstract Batch verification is a method to verify multiple digital signatures at a batch in time less than total individual verification time. Batch verification for an identity‐based signature scheme (IBS) is attractive because a short public identity such as an e‐mail address can be used as a verification key. In this paper, we first review the recent IBS scheme proposed by Shim and its batch verifier to show that the batch verifier is vulnerable to a forgery attack. In order to resist to the attack, we propose a new efficient batch verifier for the IBS scheme. The proposed batch verifier can deal with arbitrary number of signatures as a batch. We prove formally that the proposed batch verifier is secure. Then, we analyze the computation cost of the proposed batch verifier using concrete parameters and compare it with well‐known batch verifiers. The comparison shows that our batch verifier can significantly outperform the existing batch verifiers in computation. We finally present a one‐round three‐party identity‐based key agreement protocol as an application of our batch verifier, which requires only three pairing operations in verification. Copyright © 2015 John Wiley & Sons, Ltd.

The controllable linkability of group signatures introduced by Hwanget al.enables an entity who has a linking key to find whether or not two group signatures were generated by the same signer, while preserving the anonymity. This functionality is very useful in many applications that require the linkability but still need the anonymity, such as sybil attack detection in a vehicular ad hoc network and privacy-preserving data mining. In this paper, we present a new group signature scheme supporting the controllable linkability. The major advantage of this scheme is that the signature length is very short, even shorter than this in the best-known group signature scheme without supporting the linkability. We have implemented our scheme in both a Linux machine with an Intel Core2 Quad and an iPhone4. We compare the results with a number of existing group signature schemes. We also prove security features of our scheme, such as anonymity, traceability, nonframeability, and linkability, under a random oracle model.

At CCS'07, a novel identity-based sequential aggregate signature scheme was proposed and the security of the scheme was proven under the hardness assumption of a new computational problem called modified LRSW problem. In the paper, unfortunately, we show that the scheme is universally forgeable, i.e., anyone can generate forged signatures on any messages of its choice. In addition, we show that the computational assumption is not correct by concretely presenting a constant-time algorithm solving the problem. The contribution of the new scheme and assumption is a natural step in cryptologic research that calls for further investigation, which is a step we perform in the current work.

Fathi et al. recently proposed a leakage-resilient authenticated key exchange protocol for a server-client model in mobility environment over wireless links. In the paper, we address flaws in a hash function used in the protocol. The direct use of the hash function cannot guarantee the security of the protocol. We also point out that a combination of the hash function and the RSA cryptosystem in the protocol may not work securely. To remedy these problems, we improve upon the protocol by modifying the hash function correctly.

Abstract Recently, to provide data confidentiality against intermediate relaying proxies, Hur, Shin, and Yoon proposed a decentralized group key management(GKM) scheme for dynamic networks that uses proxy cryptography. We show that the GKM scheme unfortunately does not provide data confidentiality. We also present a counter measure to fix the security breaches. Copyright © 2009 John Wiley & Sons, Ltd.