198665
Enhanced smart-card based license management
In many e-commerce (electronic commerce) situations, the owner of a digital object wants to enforce policies on the object after the object is in the customer's hands. The object can be thought of as being software, because data is often protected by forcing access to it to take place through a particular authorized software (e.g., a "reader" for an encrypted media file, in which case a license to view the movie is, in some sense, a "software license"). One of the ways that were proposed for such policy enforcement is the use of smart cards. We describe an enhanced solution to software license management based on tamper-resistant smart cards. Our public-key protocols for binding software licenses to smart cards improve on previous schemes in that they support flexible and partial transfers of licenses between cards. The license is verified by checking the presence of the associated card. The user can therefore have several software licenses all of which are bound to one card, to avoid juggling several cards in and out of the card reader.
1305393
Universal Accumulators with Efficient Nonmembership Proofs
Based on the notion of accumulators, we propose a new cryptographic scheme called universal accumulators. This scheme enables one to commit to a set of values using a short accumulator and to efficiently compute a membership witness of any value that has been accumulated. Unlike traditional accumulators, this scheme also enables one to efficiently compute a nonmembership witness of any value that has not been accumulated. We give a construction for universal accumulators and prove its security based on the strong RSA assumption. We further present a construction for dynamic universal accumulators; this construction allows one to dynamically add and delete inputs with constant computational cost. Our construction directly builds upon Camenisch and Lysyanskaya's dynamic accumulator scheme. Universal accumulators can be seen as an extension to dynamic accumulators with support of nonmembership witness. We also give an efficient zero-knowledge proof protocol for proving that a committed value is not in the accumulator. Our dynamic universal accumulator construction enables efficient membership revocation in an anonymous fashion.
16974710
Trust Negotiation with Hidden Credentials, Hidden Policies, and Policy Cycles
In an open environment such as the Internet, the decision to collaborate with a stranger (e.g., by granting access to a resource) is often based on the characteristics (rather than the identity) of the requester, via digital credentials: Access is granted if Alice’s credentials satisfy Bob’s access policy. The literature contains many examples where protecting the credentials and the access control policies is useful, and there are numerous protocols that achieve this. In many of these schemes, the server does not learn whether the client obtained access (e.g., to a message, or a service via an eticket). A consequence of this property is that the client can use all of her credentials without fear of “probing” attacks by the server, because the server cannot glean information about which credentials the client has (when this property is lacking, the literature uses a framework where the very use of a credential is subject to a policy specific to that credential). The main result of this paper is a protocol for negotiating trust between Alice and Bob without revealing either credentials or policies, when each credential has its own access policy associated with it (e.g., “a top-secret clearance credential can only be used when the other party is a government employee and has a top-secret clearance”). Our protocol carries out this privacy-preserving trust negotiation between Alice and Bob, while enforcing each credential’s policy (thereby protecting sensitive credentials). Note that there can be a deep nesting of dependencies between credential policies, and that there can be (possibly overlapping) policy cycles of these dependencies. Our result is not achieved through the routine use of standard techniques to implement, in this framework, one of the known strategies for trust negotiations (such as the “eager strategy”). Rather, this paper uses novel techniques to implement a non-standard trust negotiation strategy specifically suited to this framework (and in fact unusable outside of this framework, as will become clear). Our work is therefore Portions of this work were supported by Grants IIS-0325345, IIS0219560, IIS-0312357, and IIS-0242421 from the National Science Foundation, Contract N00014-02-1-0364 from the Office of Naval Research, by sponsors of the Center for Education and Research in Information Assurance and Security, and by Purdue Discovery Park’s e-enterprise Center. a substantial extension of the state-of-the-art in privacypreserving trust negotiations.
15166718
Secure Outsourcing of Sequence Comparisons
Large-scale problems in the physical and life sciences are being revolutionized by Internet computing technologies, like grid computing, that make possible the massive cooperative sharing of computational power, bandwidth, storage, and data. A weak computational device, once connected to such a grid, is no longer limited by its slow speed, small amounts of local storage, and limited bandwidth: It can avail itself of the abundance of these resources that is available elsewhere on the network. An impediment to the use of “computational outsourcing” is that the data in question is often sensitive, e.g., of national security importance, or proprietary and containing commercial secrets, or to be kept private for legal requirements such as the HIPAA legislation, Gramm-Leach-Bliley, or similar laws. This motivates the design of techniques for computational outsourcing in a privacy-preserving manner, i.e., without revealing to the remote agents whose computational power is being used, either one's data or the outcome of the computation on the data. This paper investigates such secure outsourcing for widely applicable sequence comparison problems, and gives an efficient protocol for a customer to securely outsource sequence comparisons to two remote agents, such that the agents learn nothing about the customer's two private sequences or the result of the comparison. The local computations done by the customer are linear in the size of the sequences, and the computational cost and amount of communication done by the external agents are close to the time complexity of the best known algorithm for solving the problem on a single machine (i.e., quadratic, which is a huge computational burden for the kinds of massive data on which such comparisons are made). The sequence comparison problem considered arises in a large number of applications, including speech recognition, machine vision, and molecular sequence comparisons. In addition, essentially the same protocol can solve a larger class of problems whose standard dynamic programming solutions are similar in structure to the recurrence that subtends the sequence comparison algorithm.
62613535
OACerts: Oblivious Attribute Certificates
We propose oblivious attribute certificates (OACerts), an attribute certificate scheme in which a certificate holder can select which attributes to use and how to use them. In particular, a user can use attribute values stored in an OACert obliviously, i.e., the user obtains a service if and only if the attribute values satisfy the policy of the service provider, yet the service provider learns nothing about these attribute values. This way, the service provider's access control policy is enforced in an oblivious fashion. To enable the oblivious access control using OACerts, we propose a new cryptographic primitive called oblivious commitment-based envelope (OCBE). In an OCBE scheme, Bob has an attribute value committed to Alice and Alice runs a protocol with Bob to send an envelope (encrypted message) to Bob such that: 1) Bob can open the envelope if and only if his committed attribute value satisfies a predicate chosen by Alice and 2) Alice learns nothing about Bob's attribute value. We develop provably secure and efficient OCBE protocols for the Pedersen commitment scheme and comparison predicates as well as logical combinations of them
12958677
A Construction for General and Efficient Oblivious Commitment Based Envelope Protocols
The notion of Oblivious Commitment Based Envelope (OCBE) was recently proposed; it enables attribute-based access control without revealing any information about the attributes. Previous OCBE protocols are designed by taking zero-knowledge proof protocols that prove a committed value satisfies some property and changing the protocols so that instead of one party proving to the other party, the two parties compute two keys that agree if and only if the committed value indeed satisfy the property. In this paper, we introduce a more general approach for designing OCBE protocols that uses zero-knowledge proof protocols in a black-box fashion. We present a construction such that given a zero-knowledge proof protocol that proves a committed value satisfies a predicate, we have an OCBE protocol for that predicate with constant additional cost. Compared with previous OCBE protocols, our construction is more general, more efficient, and has wide applicability.
12669704
Observations on versioning of off-the-shelf components in industrial projects (short paper)
Using OTS (Off-The-Shelf) components in software projects has become increasing popular in the IT industry. After project managers opt for OTS components, they can decide to use COTS (Commercial-Off-The-Shelf) components or OSS (Open Source Software) components. We have done a series of interviews and surveys to document and understand industrial practice with OTS-based development in Norwegian, German, and Italian IT industry. The perspective is that of a software architect or system integrator, not a developer or maintainer of such components. The study object is a completed development project using one or several OTS components. This paper reports on the versioning aspects of OTS components in such projects. We found that one third of the COTS components actually provided source code, in addition to all OSS components. However, OTS components were seldom modified (i.e. re-used "as-is"), even if source code was available. Although backward compatibility of new releases did not cause noticeable problems for a single OTS component, using several different OTS components in a project caused difficulties in maintenance planning of asynchronous releases and system integration of new releases. Several new research questions have been formulated based on the results of this study.
40919560
MIMO Techniques in Cluster-Based Wireless Sensor Networks
Advances in microsensor and radio technology will enable small but smart sensors to be deployed for a wide range of environment monitoring applications. Most architectures of wireless sensor networks (WSN) are built as homogeneous networks, where all sensor nodes have the same structure. But it is not suitable for cluster-based WSN. By using multi-antenna sensor node (MASN) as the cluster head (CH), we import multi-input-multi-output (MIMO) and single-input-multi-output (SIMO) communication modes into WSN. In this network scenario, tremendous energy saving is possible when transmission range is larger than a given threshold. This paper motivates and describes the realization of the inhomogeneous network, special communication scheme and simulation of energy consumption and delay model of it.
15329835
Quality Evaluation in Flexible Machining Systems: A Flexible Fixture Case Study
Most of the studies in flexible manufacturing systems address the issues of flexibility, productivity, cost, etc. The impact of flexible lines on product quality is less studied. This paper presents a quantitative model based on Markov chain analysis to evaluate quality performance of a flexible machining system. A case study of flexible fixture is provided to illustrate the applicability of the method.
15668602
A Survey of Software Development with Open Source Components in Chinese Software Industry
Chinese software companies are increasingly using Open Source Software (OSS) components in system development. Integrating such components into new software systems leads to challenges related to component selection, component integration and testing, licensing compliance, and system maintenance. Although these issues have been investigated industrially in other countries, few state-of-the-practice studies have so far been performed in China and with a representative subset of software companies. It is therefore difficult for Chinese software companies to be aware of special issues, or to plan improvement of OSS-related processes. This paper describes a questionnaire-based survey in Chinese software companies of software development with existing OSS components. Data from 47 finished development projects in 43 companies have been collected. The results show that use of web search engines was the most common method to locate OSS components. Local expertise combined with requirements compliance was the most decisive factors when choosing an identified component. To avoid legal exposure, the common strategy was to use components without licensing constraints. About 84% of the components needed bug fixing or other code changes, rarely relies on support from the OSS community. However, close participation with the OSS community was rare, although most developers meant that this was important.
11813663
Complete-factors and (g, f)-factors
A factor F of a graph is called a complete-factor if each component of F is complete. Let G be a graph, F be a complete-factor of G with @w(F)>=2 and f,g be two integer-valued functions defined on V(G) with f(x)>=g(x) for all [email protected]?V(G). It is proved that if @w(F)=0(mod2), or f(V(G)) even and f(x)=g(x)(mod2) for all [email protected]?V(G), and if G-V(C) has a (g,f)-factor for each component C of F, then G has a (g,f)-factor. We show that the results in this paper are best possible.