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If you wish to be informed about our seminars by email,
please contact Francesco Berti, Olivier Pereira or François-Xavier Standaert .
Seminars for the year 2011
January 2011
January 12, 14:00 - Beyond the Limits of DPA: Combined Side-Channel Collision Attacks
by Dr. Andrey Bogdanov
, Ilya Kizhvatov
Date: | January 12, 2011 - 14:00 |
Location: | Auditoire Euler, 002, Euler Building (near Maxwell Building) Avenue Georges Lemaître, 4-6 - 1348 Louvain-la-Neuve |
Abstract: | The fundamental problem of extracting the highest possible amount of key-related information using the lowest possible number of measurements is central to side-channel attacks against embedded implementations of cryptographic algorithms. To address it, this work proposes a novel framework enhancing side-channel collision attacks with divide-and-conquer attacks such as differential power analysis (DPA). An information-theoretical metric is introduced for the evaluation of collision detection efficiency. Improved methods of dimension reduction for side-channel traces are developed based on a statistical model of Euclidean distance.
The theoretical and experimental results of this work confirm that DPA-combined collision attacks are superior to both DPA-only and collision-only attacks. The new methods of dimension reduction lead to further complexity improvements. All attacks are treated for the case of AES-128 and are practically validated on a wide-spread 8-bit RISC microcontroller whose architecture is similar to that of many smart cards.
(Slides: http://www.uclouvain.be/crypto/files/seminars/combined_slides.pdf) |
Link: | Slides |
April 2011
April 21, 11:00 - Sanitizable Signatures with Several Signers and Sanitizers
by Dr. Sébastien Canard
Date: | April 21, 2011 - 11:00 |
Location: | Auditoire Euler, 002, Euler Building (near Maxwell Building) Avenue Georges Lemaître, 4-6 - 1348 Louvain-la-Neuve |
Abstract: | Sanitizable signatures allow a signer of a message to give one specific receiver, called a sanitizer, the power to modify some designated parts of the signed message. Most of existing constructions consider one single signer giving such possibility to one single sanitizer. In this paper, we formalize the concept with $n$ signers and $m$ sanitizers, extending the work from PKC 2010 where n=1. We give several concrete instantiations, dealing with several kinds of anonymity and transparency. Our schemes are either based on trapdoor or proof or on trapdoor list signatures, two new cryptographic building blocks that may be of independent interest. |
October 2011
October 25, 11:00 - Tolerant Algebraic Side-Channel Analysis of AES
by Yossi Oren
Date: | October 25, 2011 - 11:00 |
Location: | Room 207, Euler Building (near Maxwell Building) Avenue Georges Lemaître, 4-6 - 1348 Louvain-la-Neuve |
Abstract: | Classical power analysis attacks are difficult to mount when only a single power trace is available: the statistical methods that make DPA attacks so successful are not applicable since they require many (typically thousands) of traces. Recently it was suggested by Standaert et al. to use algebraic methods for the single-trace scenario, converting the key recovery problem into a Boolean satisfiability (SAT) problem, then using a SAT solver. However, this approach is extremely sensitive to noise (allowing an error rate of well under 1% at most), and the question of its practicality remained open.
In this work we show how a single-trace side-channel analysis problem can be transformed into a pseudo-Boolean optimization (PBOPT) problem, which takes errors into consideration. We call our new attack methodology Tolerant Algebraic Side-Channel Analysis (TASCA). We will describe the new methodology, its strengths and limitations, and finally show a full TASCA-based key-recovery attack on a microcontroller-based implementation of the Advanced Encryption Standard. |
See also: