1,179 research outputs found
Combinatorial Bounds and Characterizations of Splitting Authentication Codes
We present several generalizations of results for splitting authentication
codes by studying the aspect of multi-fold security. As the two primary
results, we prove a combinatorial lower bound on the number of encoding rules
and a combinatorial characterization of optimal splitting authentication codes
that are multi-fold secure against spoofing attacks. The characterization is
based on a new type of combinatorial designs, which we introduce and for which
basic necessary conditions are given regarding their existence.Comment: 13 pages; to appear in "Cryptography and Communications
Information Theoretic Authentication and Secrecy Codes in the Splitting Model
In the splitting model, information theoretic authentication codes allow
non-deterministic encoding, that is, several messages can be used to
communicate a particular plaintext. Certain applications require that the
aspect of secrecy should hold simultaneously. Ogata-Kurosawa-Stinson-Saido
(2004) have constructed optimal splitting authentication codes achieving
perfect secrecy for the special case when the number of keys equals the number
of messages. In this paper, we establish a construction method for optimal
splitting authentication codes with perfect secrecy in the more general case
when the number of keys may differ from the number of messages. To the best
knowledge, this is the first result of this type.Comment: 4 pages (double-column); to appear in Proc. 2012 International Zurich
Seminar on Communications (IZS 2012, Zurich
Lower bounds on the probability of deception in authentication with arbitration
The paper investigates a model for authentication in which not only an outsider, but also the transmitter or the receiver, may cheat. Lower bounds on the probability of success for different types of deception as well as on the parameters of secure authentication codes are derived. The latter bounds are shown to be tight by demonstrating codes in projective space that meet the bounds with equality
Disjoint difference families and their applications
Difference sets and their generalisations to difference families arise from the study of designs and many other applications. Here we give a brief survey of some of these applications, noting in particular the diverse definitions of difference families and the variations in priorities in constructions. We propose a definition of disjoint difference families that encompasses these variations and allows a comparison of the similarities and disparities. We then focus on two constructions of disjoint difference families arising from frequency hopping sequences and showed that they are in fact the same. We conclude with a discussion of the notion of equivalence for frequency hopping sequences and for disjoint difference families
A Survey on Wireless Sensor Network Security
Wireless sensor networks (WSNs) have recently attracted a lot of interest in
the research community due their wide range of applications. Due to distributed
nature of these networks and their deployment in remote areas, these networks
are vulnerable to numerous security threats that can adversely affect their
proper functioning. This problem is more critical if the network is deployed
for some mission-critical applications such as in a tactical battlefield.
Random failure of nodes is also very likely in real-life deployment scenarios.
Due to resource constraints in the sensor nodes, traditional security
mechanisms with large overhead of computation and communication are infeasible
in WSNs. Security in sensor networks is, therefore, a particularly challenging
task. This paper discusses the current state of the art in security mechanisms
for WSNs. Various types of attacks are discussed and their countermeasures
presented. A brief discussion on the future direction of research in WSN
security is also included.Comment: 24 pages, 4 figures, 2 table
Cambodia\u27s Law on Secured Transaction
Cambodian law permits the taking of and the perfecting of a security interest in movables (e.g., goods) and in intangibles (e.g., legally enforceable rights, such as contracts and rights in property.) Cambodia’s system is strongly patterned after Article 9 of the Uniform Commercial Code as developed in the United States. Perfection (i.e. notice to third parties that a security interest exists) is usually effected by the filing of a notice at the Secured Transactions Filing Office (the “STFO”) of the Ministry of Commerce, although sometimes physical possession may be required. However, conflicting or ambiguous provisions in other Cambodian laws may adversely affect the security interest obtained and perfected under the Law on Secured Transactions. Most of these conflicting provisions are found in the Civil Code and the Pawn Shop Regulations. This Article explores key principles and nuances in Cambodia’s Law on Secured Transactions, particularly those issues related to the nature of collateral, the perfection of security interest and the risk and conflicts arising under Cambodian laws
RE-ENGINEERING THE DUTCH FLOWER AUCTIONS: A FRAMEWORK FOR ANALYZING EXCHANGE ORGANIZATIONS
This paper specifies a generalizable model of exchange processes and develops
a process-stakeholder analysis framework to evaluate alternative market
designs. This framework is applied to analyze a number of information
technology initiatives in the Dutch flower markets. The Dutch flower
auctions are the world's leading centers for trading cut-flowers and potted
plants. We undertake a cross-case analysis and apply our framework to
analyse successes and failures in the introduction of new IT-based trading
mechanisms in these markets. Based on our study, we develop a number of
testable propositions on: the separation of physical and informational
processes in trading, the responses of stakeholders to changes in available
information due to IT initiatives, and economic and incentive conditions
required for adoption of new trading processes. Finally, our detailed cases
illustrate the institutional and incentive constraints, and complexities
encountered in the introduction of new electronic markets.Information Systems Working Papers Serie
Multiparty Quantum Signature Schemes
Digital signatures are widely used in electronic communications to secure
important tasks such as financial transactions, software updates, and legal
contracts. The signature schemes that are in use today are based on public-key
cryptography and derive their security from computational assumptions. However,
it is possible to construct unconditionally secure signature protocols. In
particular, using quantum communication, it is possible to construct signature
schemes with security based on fundamental principles of quantum mechanics.
Several quantum signature protocols have been proposed, but none of them has
been explicitly generalized to more than three participants, and their security
goals have not been formally defined. Here, we first extend the security
definitions of Swanson and Stinson (2011) so that they can apply also to the
quantum case, and introduce a formal definition of transferability based on
different verification levels. We then prove several properties that multiparty
signature protocols with information-theoretic security -- quantum or classical
-- must satisfy in order to achieve their security goals. We also express two
existing quantum signature protocols with three parties in the security
framework we have introduced. Finally, we generalize a quantum signature
protocol given in Wallden-Dunjko-Kent-Andersson (2015) to the multiparty case,
proving its security against forging, repudiation and non-transferability.
Notably, this protocol can be implemented using any point-to-point quantum key
distribution network and therefore is ready to be experimentally demonstrated.Comment: 22 pages, 4 figure
Framework for privacy-aware content distribution in peer-to- peer networks with copyright protection
The use of peer-to-peer (P2P) networks for multimedia distribution has spread out globally in recent years. This mass popularity is primarily driven by the efficient distribution of content, also giving rise to piracy and copyright infringement as well as privacy concerns. An end user (buyer) of a P2P content distribution system does not want to reveal his/her identity during a transaction with a content owner (merchant), whereas the merchant does not want the buyer to further redistribute the content illegally. Therefore, there is a strong need for content distribution mechanisms over P2P networks that do not pose security and privacy threats to copyright holders and end users, respectively. However, the current systems being developed to provide copyright and privacy protection to merchants and end users employ cryptographic mechanisms, which incur high computational and communication costs, making these systems impractical for the distribution of big files, such as music albums or movies.El uso de soluciones de igual a igual (peer-to-peer, P2P) para la distribución multimedia se ha extendido mundialmente en los últimos años. La amplia popularidad de este paradigma se debe, principalmente, a la distribución eficiente de los contenidos, pero también da lugar a la piratería, a la violación del copyright y a problemas de privacidad. Un usuario final (comprador) de un sistema de distribución de contenidos P2P no quiere revelar su identidad durante una transacción con un propietario de contenidos (comerciante), mientras que el comerciante no quiere que el comprador pueda redistribuir ilegalmente el contenido más adelante. Por lo tanto, existe una fuerte necesidad de mecanismos de distribución de contenidos por medio de redes P2P que no supongan un riesgo de seguridad y privacidad a los titulares de derechos y los usuarios finales, respectivamente. Sin embargo, los sistemas actuales que se desarrollan con el propósito de proteger el copyright y la privacidad de los comerciantes y los usuarios finales emplean mecanismos de cifrado que implican unas cargas computacionales y de comunicaciones muy elevadas que convierten a estos sistemas en poco prácticos para distribuir archivos de gran tamaño, tales como álbumes de música o películas.L'ús de solucions d'igual a igual (peer-to-peer, P2P) per a la distribució multimèdia s'ha estès mundialment els darrers anys. L'àmplia popularitat d'aquest paradigma es deu, principalment, a la distribució eficient dels continguts, però també dóna lloc a la pirateria, a la violació del copyright i a problemes de privadesa. Un usuari final (comprador) d'un sistema de distribució de continguts P2P no vol revelar la seva identitat durant una transacció amb un propietari de continguts (comerciant), mentre que el comerciant no vol que el comprador pugui redistribuir il·legalment el contingut més endavant. Per tant, hi ha una gran necessitat de mecanismes de distribució de continguts per mitjà de xarxes P2P que no comportin un risc de seguretat i privadesa als titulars de drets i els usuaris finals, respectivament. Tanmateix, els sistemes actuals que es desenvolupen amb el propòsit de protegir el copyright i la privadesa dels comerciants i els usuaris finals fan servir mecanismes d'encriptació que impliquen unes càrregues computacionals i de comunicacions molt elevades que fan aquests sistemes poc pràctics per a distribuir arxius de grans dimensions, com ara àlbums de música o pel·lícules
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