International Association for Cryptologic Research

# IACR News Central

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2013-03-06
00:07 [Job][New]

In view of its ongoing development, the crypto group of the University of Versailles St-Quentin-en-Yvelines (France) invites applications for the following full-time position.

A faculty position at the tenured Assistant Professor (\\\"Maître de Conférences\\\") level is open to highly qualified candidates who are committed to a career in research and teaching. Preference will be given to candidates with strong research achievements in one or several of the areas related to the general fields of cryptology and/or information security.

Responsibilities include research, supervision of undergraduates and graduate students, preparation and management of research projects, and teaching in various study programs.

IMPORTANT NOTE: A \\\"qualification aux fonctions de Maître de Conférences\\\" certificate from to the French \\\"Conseil National des Universités\\\" is usually required to apply. However candidates who already hold an Assistant Professor (or equivalent) position may be exempted from this certificate.

00:07 [Job][New]

The Cryptography, Security, and Privacy (CrySP) research group at the University of Waterloo is seeking applications for a postdoctoral research position in the field of security and privacy for location-based or mobile systems and applications. This position will be held in the Cheriton School of Computer Science, and there will be the possibility for collaboration with Google Waterloo.

Applicants must hold a PhD in a related field and should have a convincing publication record.

The start date of the position is negotiable. The position may be for one or two years.

Applicants should submit a CV, a research plan, two or three selected papers, and the names and contact information of three references.

2013-03-05
15:25 [Job][New]

The Digital Security (DS) group of RU Nijmegen has a PhD position in side-channel analysis and countermeasure design and implementation.

Candidates should have a Master’s degree in computer science, applied mathematics or engineering with strong interest in algorithms and signal processing. Prior experience in side-channel analysis and embedded software or hardware design is an asset.

This research addresses potential threats within the scope of side-channel analysis and fault injection. The successful candidate will contribute to a research project entitled Side-channel resistant devices for pervasive security (SIDES), which is funded by STW. The project is a joint collaboration with Riscure.

Conditions of employment

The position is for 4 years, the expected starting date is flexible, preferably not later than September. Salary is 2042-2612 euro/month.

Candidates moving to the Netherlands from abroad may qualify for a tax incentive scheme, where 30% of your income is tax free.

15:24 [Job][New]

INVIA provides security-related semiconductor design IP and embedded software to ASIC and FPGA designers. Our customers are semiconductor vendor and OEM addressing markets where security is a key requirement.

Description

The integrated circuit designer will work in the R&D digital team and will contribute to the development of innovative IP for secure products. Main activities include various technical aspects as target specifications, technology survey, architecture, concept, IP development and validation, prototyping, IP packaging, documentation, etc.

He could be also visible from customers side in relationship with Invia marketing through market needs enquiries, technical meeting, deliveries to the customer, field support, etc.

Qualifications

PhD Degree in digital IC design, cryptography, MSc Degree in electrical engineering or equivalent.

Permanent position. The gross income depends on the experience level. Min package is about 40,000 EUR per year.

13:17 [Pub][ePrint]

We present several software and hardware implementations of QUAD, a recently introduced stream cipher designed to be provably secure and practical to implement. The software implementations target both a personal computer and an ARM microprocessor. The hardware implementations target field programmable gate arrays. The purpose of our work was to first find the baseline performance of QUAD implementations, then to optimize our implementations for throughput. Our software implementations perform comparably to prior work. Our hardware implementations are the first known implementations to use random coefficients, in agreement with QUAD\'s security argument, and achieve much higher throughputs than prior implementations.

13:17 [Pub][ePrint]

At Pairing 2010, Lauter et al\'s analysis showed that Ate pairing computation in affine coordinates may be much faster than projective coordinates at high security levels. In this paper, we further investigate techniques to speed up Ate pairing computation in affine coordinates. We first analyze Ate pairing computation using $4$-ary Miller algorithm in affine coordinates. This technique allows us to trade one multiplication in the full extension field and one field inversion for several multiplications in a smaller field. Then, we focus on pairing computations over elliptic curves admitting a twist of degree $3$. We propose new fast explicit formulas for Miller function that are comparable to formulas over even twisted curves. We further analyze pairing computation on cubic twisted curves by proposing efficient subfamilies of pairing-friendly elliptic curves with embedding degrees $k = 9$, and $15$. These subfamilies allow us not only to obtain a very simple form of curve, but also lead to an efficient arithmetic and final exponentiation.

13:17 [Pub][ePrint]

Attribute-based credentials (ABCs) are an important building block of privacy-enhancing identity management. Since non-identifying attributes can easily be abused as the anonymity they provide hides the perpetrator, cryptographic mechanisms need to be introduced to make them revocable. However, most of these techniques are not efficient enough in practice.

ABCs with practical revocation have recently been proposed by Hajny and Malina~\\cite{Hajny-Malina-2012}. Their ABCs make use of different discrete logarithm representations of a fixed value. Although this technique is attractive as the verification of a particular issuer\'s credentials is easy, it has an intrinsic weakness. Colluding users can efficiently forge new credentials that are indistinguishable from legally issued ones.

13:17 [Pub][ePrint]

Recently, Gennaro, Gentry, Parno and Raykova~\\cite{eprint2012:GennaroGPR} proposed an efficient non-interactive zero knowledge argument for Circuit-SAT, based on non-standard notions like conscientious and quadratic span programs. We propose a new non-interactive zero knowledge argument, based on a simple combination of \\emph{standard} span programs (that verify the correctness of every individual gate) and high-distance linear error-correcting codes (that check the consistency of wire assignments). We simplify all steps of the argument. As one of the corollaries, we design an (optimal) wire checker, based on systematic Reed-Solomon codes, of size $8 n$ and degree $4 n$, while the wire checker from~\\cite{eprint2012:GennaroGPR} has size $24 n$ and degree $76 n$, where $n$ is the circuit size. Importantly, the new argument has constant verifier\'s computation.

13:17 [Pub][ePrint]

RIPEMD-128 is an ISO/IEC standard cryptographic hash function proposed

in 1996 by Dobbertin, Bosselaers and Preneel. There are two

different and independent parallel lines called $line1$ operation and

$line2$ operation, and each operation has 64 steps. The results of two

line operations are combined at the end of every application of the

compression function. In this paper, we present collision

differential characteristics for both $line1$ operation and $line2$ operation by choosing a proper message difference. By using message modification technique seriously, we improve the probabilities of the differential characteristics so that we can give a collision attack on 40-step RIPEMD-128 with a complexity of $2^{35}$ computations.

13:17 [Pub][ePrint]

In 2011, Lindell proposed an efficient commitment scheme, with a non-interactive opening algorithm, in the Universal Composability (UC) framework. He recently acknowledged a bug in its security analysis for the adaptive case. We analyze the proof of the original paper and propose a simple patch of the scheme.

More interestingly, we then modify it and present a more efficient commitment scheme secure in the UC framework, with the same level of security as Lindell\'s protocol: adaptive corruptions, with erasures. The

security is proven in the standard model (with a Common Reference String) under the classical Decisional Diffie-Hellman assumption. Our proposal is the most efficient UC-secure commitment proposed to date (in

terms of computational workload and communication complexity).

13:17 [Pub][ePrint]

We initiate a general study of schemes resilient to both tampering and leakage attacks. Tampering attacks are powerful cryptanalytic attacks where an adversary can change the secret state and observes the effect of such changes at the output. Our contributions are outlined below:

(1) We propose a general construction showing that any cryptographic primitive where the secret key can be chosen as a uniformly random string can be made secure against bounded tampering and leakage. This holds in a restricted model where the tampering functions must be chosen from a set of bounded size after the public parameters have been sampled. Our result covers pseudorandom functions, and many encryption and signature schemes.

(2) We show that standard ID and signature schemes constructed from a large class of Sigma-protocols (including the Okamoto scheme, for instance) are secure even if the adversary can arbitrarily tamper with the prover\'s state a bounded number of times and/or obtain some bounded amount of leakage. Interestingly, for the Okamoto scheme we can allow also independent tampering with the public parameters.

(3) We show a bounded tamper and leakage resilient CCA secure public key cryptosystem based on the DDH assumption. We first define a weaker CPA-like security notion that we can instantiate based on DDH, and then we give a general compiler that yields CCA-security with tamper and leakage resilience. This requires a public tamper-proof common reference string.

(4) Finally, we explain how to boost bounded tampering and leakage resilience (as in 2. and 3. above) to continuous tampering and leakage resilience, in the so-called floppy model where each user has a personal floppy (containing leak- and tamper-free information) which can be used to refresh the secret key (note that if the key is not updated, continuous tamper resilience is known to be impossible). For the case of ID schemes, we also show that if the underlying protocol is secure in the bounded retrieval model, then our compiler remains secure, even if the adversary can tamper with the computation performed by the device.

In some earlier work, the implementation of the tamper resilient primitive was assumed to be aware of the possibility of tampering, in that it would switch to a special mode and, e.g., self-destruct if tampering was detected. None of our results require this assumption.