International Association for Cryptologic Research

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2012-09-20
12:17 [Pub][ePrint]

Multiplication of three elements over finite fields is used extensively in multivariate public key cryptography and solving system of linear equations over finite fields. This contribution shows the enhancements of multiplication of three elements over finite fields by using specific architecture. We firstly propose a versatile multi-input multiplier over finite fields. The parameters of this multiplier can be changed according to the requirement of the users which makes it reusable in different applications. Our evaluation of this multiplier gives optimum choices for multiplication of three elements over finite fields. Implemented results show that we takes $22.062$ ns and $16.354$ ns to execute each multiplication of three elements over $GF((2^4)^2)$ based on table look-up and polynomial basis on a FPGA respectively. Experimental results and mathematical proofs clearly demonstrate the improvement of the proposed versatile multiplier over finite fields.

09:17 [Pub][ePrint]

In this paper, we propose an elaborate geometry approach to explain the group law on twisted Edwards curves which are seen as the intersection of quadric surfaces in place. Using the geometric interpretation of the group law we obtain the Miller function for Tate pairing computation on twisted Edwards curves. Then we present the explicit formulae for pairing computation on twisted Edwards curves. Our formulae for the doubling step are a littler faster than that proposed by Arene et.al.. Finally, to improve the efficiency of pairing computation we present twists of degree 4 and 6 on twisted Edwards curves.

09:17 [Pub][ePrint]

This paper is a tutorial introduction to the present state-of-the-art in the field of security of lattice-based cryptosystems. After a short introduction to lattices, we describe the main hard problems in lattice theory that cryptosystems base their security on, and we present the main methods of attacking these hard problems, based on lattice basis reduction. We show how to find shortest vectors in lattices, which can be used to improve basis reduction algorithms. Finally we give a framework for assessing the security of cryptosystems based on these hard problems.

09:17 [Pub][ePrint]

We give easy proofs of some recent results concerning threshold gaps in ramp schemes. We then give a simplified and unified treatment of construction methods for ramp schemes using error-correcting codes. Finally, as an immediate consequence of these results, we provide a new explicit bound on the the minimum length of a code having a specified distance and dual distance.

09:17 [Pub][ePrint]

This article describes the design of an 8-bit coprocessor for the AES (encryption, decryption, and key expansion) and the cryptographic hash function Gr{\\o}stl on several Xilinx FPGAs. Our Arithmetic and Logic Unit performs a single instruction that allows for implementing AES encryption, AES decryption, AES key expansion, and Gr{\\o}stl at all levels of security. Thanks to a careful organization of AES and Gr{\\o}stl internal states in the register file, we manage to generate all read and write addresses by means of a modulo-128 counter and a modulo-256 counter. A fully autonomous implementation of Gr{\\o}stl and AES on a Virtex-6 FPGA requires 169 slices and a single 36k memory block, and achieves a competitive throughput. Assuming that the security guarantees of Gr{\\o}stl are at least as good as the ones of the other SHA-3 finalists, our results show that Gr{\\o}stl is the best candidate for low-area cryptographic coprocessors.

09:17 [Pub][ePrint]

We present a construction of log-depth formulae for various threshold functions based on atomic threshold gates of constant size. From this, we build a new family of linear secret sharing schemes that are multiplicative, scale well as the number of players increases and allows to raise a shared value to the characteristic of the underlying field without interaction. Some of these schemes are in addition strongly multiplicative. Our formulas can also be used to construct multiparty protocols from protocols for a constant number of parties. In particular we implement black-box multiparty computation over non-Abelian groups in a way that is much simpler than previously known and we also show how to get a protocol in this setting that is efficient and actively secure against a constant fraction of corrupted parties, a long standing open problem. Finally, we show a negative result on usage of our scheme for pseudorandom secret sharing as defined by Cramer, Damgård and Ishai.

09:17 [Pub][ePrint]

We continue the recent trend in cryptography to study protocol design

in presence of tamper-proof hardware tokens. We present a very efficient

protocol for password-based authenticated key exchange based on the weak model of one-time memory tokens, recently introduced by Goldwasser et al. (Crypto~2008). Our protocol only requires four moves, very basic operations, and the sender to send $\\ell$ tokens in the first step for passwords of length $\\ell$. At the same time we achieve information-theoretic security in Canetti\'s universal composition framework (FOCS~2001) against adaptive adversaries (assuming reliable erasure), even if the tokens are not guaranteed to be transferred in an authenticated way, i.e., even if the adversary can read or substitute transmitted tokens (as opposed to many previous efforts).

06:59 [Event][New]

Submission: 12 November 2012
From November 12 to November 14
Location: Piscataway, USA

06:59 [Event][New]

From February 4 to February 7
Location: Tel-Aviv area, Israel

06:58 [Job][New]

****2 Ph.D. Positions in Computer Security (Ref: SNT-PhD-STAST-0512)****

The University of Luxembourg has two open Ph.D. positions at its

Interdisciplinary Centre for Security, Reliability and Trust (SnT)

(http://wwwen.uni.lu/snt). We are seeking Ph.D. candidates to

participate in the activities of the SaToSS

(http://satoss.uni.lu/) and of the ApSIA (http://apsia.gforge.uni.lu/)

research groups.

Project description:

----------------------

The main objective of the Ph.D. project is to develop a formal

framework supporting modeling and analysis of socio-technical

components of information systems. We aim to develop strategies and

tools to detect and prevent attacks involving human, physical and

digital elements. One of the goals is to extend current methodology

for security protocol analysis, by taking human behavior and

properties of physical objects into account. This goal includes a

necessity of defining appropriate adversary models and identifying the

security properties relevant in a socio-technical context.

Applicant\'s profile:

--------------------

* MSc in Computer Science or Mathematics

* A proven interest in security

* Strong background in formal methods or logics

* Good written and oral English skills

Start date: As soon as possible

06:57 [Job][New]

The Digital Security group at the Radboud University Nijmegen has a

vacancy for a full-time assistant professorship (Universitair Docent

UD in Dutch).

General information

Research in the group covers a range of topics including correctess

and security of software, smartcards and RFID, design and analysis of

security protocols, applied crypto, privacy and anonimity, quantum

logic and computing. Members of the group are also active in the

broader societal issues surrounding security & privacy, and regulary

carry out commercial contract research to apply and inspire high

The group runs a joint Master programme in Computer Security in

collaboration with the universities of Twente and Eindhoven, named the

Kerckhoffs Institute (www.kerckhoffs-institute.org). In Nijmegen the

Institute for Computing and Information Sciences runs Bachelor and

Master courses in Computer Science (Informatica) and Information

Science (Informatiekunde).

For this position we are looking for the best candidate in the broader

field of security, who can be a good addition to the group and has

good synergy with ongoing research in the group, who is a team player,

and who can teach computer security to a broad range of students.