In this paper, we consider the problem of ensuring fairness in systems serving a mixture of fully backlogged applications, which continuously demand resources, and non-fully backlogged applications. We introduce a fairness metric, called interference fairness, the basic idea underlying which is that the interference caused by application A for another application B should be equal to that caused by B for A. To effectively and efficiently guarantee this fairness metric, we propose Mutual Fair Allocation Policy (MFAP), a simple and powerful resource sharing policy, and show how it guarantees interference fairness between any pair of applications. We also show that MFAP, unlike other viable policies, satisfies several highly desirable properties, including some from game theory, as well as common sense intuitions. As a use case, we implemented MFAP on a disk scheduling framework. The experimental results based on synthetic and real workloads show how our implementation achieved interference fairness and improved non-fully backlogged applications performance.

E-voting techniques and systems have not been widely accepted and deployed by society due to various concerns and problems. One particular issue associated with many existing e-voting techniques is the lack of transparency, leading to the failure to deliver voter assurance. In this work, we propose an assurable, transparent, and mutual restraining e-voting protocol that exploits the existing two-party political dynamics in the US. The proposed e-voting protocol consists of three original technical contributions — universal verifiable voting vector, forward and backward mutual lock voting, and in-process check and enforcement — that, in combination, resolves the apparent conflicts in voting such as anonymity vs. accountability and privacy vs. verifiability. Especially, the trust is split equally among tallying authorities who have conflicting interests and will technically restrain each other. The voting and tallying processes are transparent to voters and any third party, which allow any voter to verify that his vote is indeed counted and also allow any third party to audit the tally.

A large portion of system breaches are caused by authentication failure, either during the login process or in the post-authentication session; these failures are themselves related to the limitations associated with existing authentication methods. Current authentication methods, whether proxy based or biometrics based, are not user-centric and/or endanger users’ (biometric) security and privacy. In this paper, we propose a biometrics based user-centric authentication approach. This method involves introducing a reference subject (RS), securely fusing the user’s biometrics with the RS, generating a BioCapsule (BC) from the fused biometrics, and employing BCs for authentication. Such an approach is user friendly, identity bearing yet privacy-preserving, resilient, and revocable once a BC is compromised. It also supports “one-click sign-on” across systems by fusing the user’s biometrics with a distinct RS on each system. Moreover, active and non-intrusive authentication can be automatically performed during post-authentication sessions. We formally prove that the secure fusion based approach is secure against various attacks. Extensive experiments and detailed comparison with existing approaches show that its performance (i.e., authentication accuracy) is comparable to existing typical biometric approaches and the new BC based approach also possesses many desirable features such as diversity and revocability.

User authentication is critical in preventing system breaches. Existing authentication approaches usually do a onetime log-in authentication, but rarely incorporate mechanisms to differentiate the initial log-in user and the user who is currently taking control of the system, which may cause post-authentication breaches. In this paper, we study user authentication for both login session and post-authentication session and propose a biometrics based active authentication approach. Moreover, concerning the usage of biometrics, the system is biometrics-secure and privacy-preserving. Security analysis and experimental results prove that the proposed approach is secure, resilient to various attacks and effective.

Authentication is a fundamental issue to any trust-oriented computing system and also a critical part in many security protocols. Performing authentication is notoriously difficult. Biometrics has been widely used and adopted as a promising authentication method due to its advantages over some existing methods, particularly, its resistance to losses incurred by theft of passwords and smart cards. However, biometrics introduces its own challenges, such as being irreplaceable once compromised. Moreover, the use of biometrics introduces privacy concern. In this paper, we propose a simple yet effective biometrics-based authentication solution. The proposed approach introduces new constructs - Reference Subject and Biometric Capsule, and stores the ``difference'' (called Biometric Capsule) between the user and the Reference Subject for authentication without revealing a user's original biometric information. This approach supports replaceability and protect users' privacy. Moreover, the proposed approach creates more advantages: (a) being user-friendly without any additional burden on users and possessing one-for-all power; (b) being generic enough to be applied to various biometrics (e.g., fingerprint, face, iris) or combinations of them; and (c) being adaptive in terms of security and privacy to fit different authentication models, application requirements, available resources, and trusted or non-fully-trusted environments. The experimental results on iris validate its performance and prove it a practical mechanism.

Secret sharing is important in information and network security and has broad applications in the real world. Since an elegant secret sharing mechanism was first proposed by Shamir in 1979, many schemes have appeared in literature. These schemes deal with either single or multiple secrets and their shares have either the same weight or different weights. Weighted shares mean that different shares have different capabilities in recovering the secret(s) -- a more (less) weighted share needs fewer (more) other shares to recover the secret(s). In this paper, we identify a direct relation between the length (i.e., the number of bits) and the weight of shares and, based on this relation, present a new Chinese Remainder Theorem (CRT) based weighted multiple secret sharing scheme. This scheme can also be naturally applied to other cases such as sharing a single secret with same-weight shares and is remarkably simple and easy to implement. Compared to both Shamir's scheme and Mignotte's scheme -- the representative of existing CRT based secret sharing schemes, the new scheme is more efficient than both schemes in share computation and more efficient than Shamir's scheme (and as efficient as Mignotte's scheme) in secret recovery. One prominent advantage of the new scheme is that the sizes of shares can vary distantly to fit different requirements and constraints of various devices such as sensors, PDAs, cell phones, iPads, hence, the new scheme is able to apply to broader applications involving wireless/sensor networks and pervasive computing.

Embedding user subscription time into cryptographic key generation and assignment for hierarchical access control has raised tremendous interest among researchers and practitioners in multicast, broadcast, and secure group communication fields. During the subscription period, a user of a higher class can compute the (time-bound) keys of his/her own class and also derive the keys of all its descendant classes in the access hierarchy. However, after the subscription expires, the user cannot compute/derive the keys. Unfortunately, due to the inclusion of time in the keys, existing schemes either suffer from (colluding) attacks or are only applicable to static access hierarchies. In this paper, we propose a new key generation and assignment scheme for this kind of time-bound hierarchy access control. The new scheme is able not only to prevent colluding attacks but also to support dynamics of access hierarchies in a simple and efficient way.