Memory-saving computation of the pairing final exponentiation on BN curves, by Sylvain DUQUESNE and Loubna GHAMMAM
In this paper, we describe and improve efficient methods for computing
the hard part of the final exponentiation of pairings on Barreto-Naehrig
Thanks to the variants of pairings which decrease the length of the Miller
loop, the final exponentiation has become a significant component of the
overall calculation. Here we exploit the structure of BN curves to improve
We will first present the most famous methods in the literature that en-
sure the computing of the hard part of the final exponentiation. We are
particularly interested in the memory resources necessary for the implementation of these methods. Indeed, this is an important constraint in
More precisely, we are studying Devegili et al. method, Scott et al. addition chain method and Fuentes et al. method. After recalling these methods and their complexities, we determine the number of required registers
to compute the final result, because this is not always given in the literature. Then, we will present new versions of these methods which require
less memory resources (up to 37%). Moreover, some of these variants are
providing algorithms which are also more efficient than the original ones.
Zero-knowledge Argument for Polynomial Evaluation with Application to Blacklists, by Stephanie Bayer and Jens Groth
Verification of a polynomial\'s evaluation in a secret committed value plays a role in cryptographic applications such as non-membership or membership proofs. We construct a novel special honest verifier zero-knowledge argument for correct polynomial evaluation. The argument has logarithmic communication cost in the degree of the polynomial, which is a significant improvement over the state of the art with cubic root complexity at best. The argument is relatively efficient to generate and very fast to verify compared to previous work. The argument has a simple public-coin 3-move structure and only relies on the discrete logarithm assumption.
The polynomial evaluation argument can be used as a building block to construct zero-knowledge membership and non-membership arguments with communication that is logarithmic in the size of the blacklist. Non-membership proofs can be used to design anonymous blacklisting schemes allowing online services to block misbehaving users without learning the identity of the user. They also allow the blocking of single users of anonymization networks without blocking the whole
SCA Resistance Analysis of Sponge based MAC-PHOTON, by N. Nalla Anandakumar
PHOTON is a lightweight hash function which was proposed
by Guo et al. in CRYPTO 2011 for low-resource ubiquitous computing
devices such as RFID tags, wireless sensor nodes and smart cards. In
this paper, we analyze Side-Channel Attack (SCA) resistance of FPGA
(Field-Programmable Gate Array) implementations of the PHOTON, when
it is used with a secret key to generate a Message Authentication Code (MAC). First, we describe three architectures of the MAC-PHOTON based on the concepts of iterative, folding and unrolling, and we provide their performance results on the Xilinx Virtex-5 FPGAs. Second, we analysed security of the MAC-PHOTON against side-channel attack using a SASEBOGII development board.
Evaluating the Duplication of Dual-Rail Precharge Logics on FPGAs, by Alexander Wild and Amir Moradi and Tim Güneysu
Power-equalization schemes for digital circuits aim to harden cryptographic designs against power analysis attacks. With respect to dual-rail logics most of these schemes have originally been designed for ASIC platforms, but much efforts have been spent to map them to FPGAs as well. A particular challenge is here to apply those schemes to the predefined logic structures of FPGAs (i.e., slices, LUTs, FFs, and routing switch boxes) for which special tools are required. Due to the absence of such routing tools Yu and Schaumont presented the idea of duplicating (i.e., dualizing) a fully-placed-and-routed dual-rail precharge circuit with equivalent routing structures on an FPGA. They adopted such architecture from WDDL providing the Double WDDL (DWDDL)scheme.
In this work we show that this general technique - regardless of the underlying dual-rail logic - is incapable to properly prevent side-channel leakages. Besides theoretical investigations on this issue we present practical evaluations on a Spartan-6 FPGA to demonstrate the flaws in such an approach. In detail, we consider an AES-128 encryption module realized by three dual-rail precharge logic styles as a case study and show that none of those schemes can provide the desired level of protection.
Research Scientist, Senior Research Scientist, Nanyang Technological University, Singapore
Tamesek Laboratories at Nanyang Technological University in Singapore is looking for both junior and senior researchers, to fill 3 positions of Research Scientists, or Senior Research Scientists, on the areas of symmetric key cryptography and lightweight cryptography. Both fresh PhD and experienced researchers are welcome to apply.
Salaries are globally competitive and are determined according to the successful applicants accomplishments, experience and qualifications. Review process starts immediately and will continue until all positions are filled.
Ph.D. position, Ruhr-University Bochum, Horst-Goertz Institute
We are looking for outstanding candidates for a PhD position with strong interest in cryptography, and in particular practice-oriented provable security. Topics of interest may include: provable security of cryptographic implementations, security analysis of random number generators, cryptographic protocols, computer-assisted security proofs.
The PhD position is funded by the the DFG Research Training Group UbiCrypt, which is part of the Horst-Goertz-Institute. The Horst-Görtz-Institut is a leading university-based institution for interdisciplinary research in the field of IT security and cryptography and offers an attractive research environment.
Applicants are required to have completed (or be close to completing) a Bachelor, Master, or Diplom with outstanding grades in Computer Science, Mathematics, or closely related areas. Additional knowledge in related disciplines such as, e.g., complexity theory or IT security is welcome. The working and teaching language is English.
Please send your application to Sebastian Faust via e-mail. Applications should contain a CV, a short letter of motivation, copies of transcripts and certificates, and (if possible) names of references. Review of applications will start immediately until the position has been filled.