IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
29 January 2016
Shahram Rasoolzadeh, Håvard Raddum
28 January 2016
Qiang Tang, Balazs Pejo, Husen Wang
Ge Bai \and Ivan Damgård \and Claudio Orlandi \and Yu Xia
By non-interactive we mean that the dealer needs to be active only once, where he posts a public message as well as a private message to each shareholder. In the random oracle model, we can even avoid interaction between shareholders. By efficient, we mean that we avoid generic zero-knowledge techniques.
Such efficient constructions were previously only known from linear secret sharing schemes (LSSS). It is believed that the class of access structures that can be handled with polynomial size LSSS is incomparable to the class that can be recognized by polynomial size monotone circuits, so in this sense we extend the class of access structures with efficient and non-interactive VSS.
Shahram Rasoolzadeh, H\aa vard Raddum
In this paper, by exploiting several properties of the KATAN round function as well as the slow diffusion of key bits, we propose some techniques to extend the number of rounds covered by multidimensional meet in the middle attack on all versions of the KATAN family of block ciphers. Our results show that this method can attack up to 206, 148 and 129 reduced-round versions of KATAN32, KATAN48 and KATAN64, respectively, with only 2 or 3 pairs of known plaintext. This cryptanalysis covers the highest number of rounds to date.
Our work is still far from a full-round attack, so it could not be considered as a threat to this family of block ciphers yet. We state that KATAN is still safe to use.
Xi-Jun Lin, Haipeng Qu, Xiaoshuai Zhang
Gajraj Kuldeep, Devendra Kumar Yadav, A. K. Sharma
27 January 2016
City University London, London, United Kingdom
Person Specification: The candidate should have a PhD in Computer Science or Engineering with interest in cryptography and Cloud Security and should have strong mathematical and C++ programming skills. In addition the person is expected to show excellent verbal and written communication skills and also a good track record of publications in IEEE Security & Privacy journals and conferences.
Closing date for applications: 25 February 2016
Contact: Professor M Rajarajan
More information: http://www.jobs.ac.uk/job/AUC165/research-associate/
Carmit Hazay, Muthuramakrishnan Venkitasubramaniam
As our second contribution, we provide a general transformation to construct a randomized encoding of a function $f$ from any 2PC protocol that securely computes a related functionality (in a black-box way). We show that if the 2PC protocol has mild adaptive security guarantees then the resulting randomized encoding (RE) can be decomposed to an offline/online encoding.
As an application of our techniques, we show how to improve the construction of Lapidot and Shamir (Crypto`90) to obtain ``input-delayed'' ZK proofs which are proofs where the honest prover's algorithm does not require the actual statement until the last round. Our transformation also yields the simplest constructions of both static and adaptive ZK proofs from standard 2PC protocols of Yao and Goldreich-Micali-Wigderson.
Jinsheng Zhang, Wensheng Zhang, Daji Qiao
26 January 2016
Karthikeyan Bhargavan, Christina Brzuska, Cédric Fournet, Matthew Green, Markulf Kohlweiss, Santiago Zanella-Béguelin
How to support configurability while at the same time guaranteeing the preferred mode is negotiated? We set to answer this question by designing a formal framework to study downgrade resilience and its relation to other security properties of key-exchange protocols. First, we study the causes of downgrade attacks by dissecting and classifying known and novel attacks against widely used protocols. Second, we survey what is known about the downgrade resilience of existing standards. Third, we combine these findings to define downgrade security, and analyze the conditions under which several protocols achieve it. Finally, we discuss patterns that guarantee downgrade security by design, and explain how to use them to strengthen the security of existing protocols, including a newly proposed draft of TLS 1.3.
Alex Biryukov, Léo Perrin, Aleksei Udovenko
In this paper, we reverse-engineer this S-Box and reveal its hidden structure. It is based on a sort of 2-round Feistel Network where exclusive-or is replaced by a finite field multiplication. This structure is hidden by two different linear layers applied before and after. In total, five different 4-bit S-Boxes, a multiplexer,two 8-bit linear permutations and two finite field multiplications in a field of size $2^{4}$ are needed to compute the S-Box.
The knowledge of this decomposition allows a much more efficient hardware implementation by dividing the area and the delay by 2.5 and 8 respectively. However, the small 4-bit S-Boxes do not have very good cryptographic properties. In fact, one of them has a probability 1 differential.
We then generalize the method we used to partially recover the linear layers used to whiten the core of this S-Box and illustrate it with a generic decomposition attack against 4-round Feistel Networks whitened with unknown linear layers. Our attack exploits a particular pattern arising in the Linear Approximations Table of such functions.
Kamil Kluczniak
Gergei Bana, Rohit Chadha
Yongge Wang
Henry Carter, Patrick Traynor
25 January 2016
Moscow, Russia, 6 July - 8 July 2016
Submission deadline: 26 June 2016
Notification: 10 July 2016
University of Oxford
Closing date for applications: 5 February 2016
Contact: James Worrell (jbw (at) cs.ox.ac.uk)
More information: http://www.cs.ox.ac.uk/news/1048-full.html
University of Mannheim, Germany
Wir suchen Kandidaten mit abgeschlossener Promotion und nachgewiesenen Kompetenzen in mindestens einen der Bereiche „Angewandte IT-Sicherheit“ und „Datenanalyse“ und die Bereitschaft, sich gegebenenfalls in den anderen einzuarbeiten. Zu den Aufgaben gehören die eigenständige Beantragung und Durchführung von Forschungsprojekten sowie die fachliche Betreuung der entsprechenden Projektmitarbeiter. Erfahrungen in der Kooperation mit der Wirtschaft sind ein Vorteil. Die Position ist zunächst auf ein Jahr befristet. Es besteht die Option auf eine Verlängerung im Rahmen der üblichen Befristungsregelungen.
Aussagekräftige Bewerbungen sind möglichst in elektronischer Form zu richten an stuckenschmidt (at) uni-mannheim.de. Für Rückfragen stehen Prof. Stuckenschmidt und Prof. Armknecht zur Verfügung. Weitere Informationen zum InES finden sich im Web (http://www.ines.uni-mannheim.de).
Closing date for applications:
Contact: Prof. Heiner Stuckenschmidt - stuckenschmidt (at) uni-mannheim.de