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05 July 2023
Tolun Tosun, Erkay Savas
Tomer Ashur, Al Kindi, Mohammad Mahzoun
In this paper, we propose two new AO hash functions, XHash8 and XHash12 which are designed based on improving the bottlenecks in RPO [ePrint 2022/1577]. Based on our experiments, XHash8 performs $\approx2.75$ times faster than RPO, and XHash12 performs $\approx2$ times faster than RPO, while at the same time inheriting the security and robustness of the battle-tested Marvellous design strategy.
Evgeny Alekseev, Alexandra Babueva, Olga Zazykina
Leonie Reichert
Ruize Wang, Martin Brisfors, Elena Dubrova
Yevgeniy Dodis, Niels Ferguson, Eli Goldin, Peter Hall, Krzysztof Pietrzak
We revisit this pessimistic state of affairs, motivated by the observation that collision-resistance is insufficient for many applications of cryptographic hash functions anyway. We argue the right formulation of the "hash combiner" is what we call random oracle (RO) combiners.
Indeed, we circumvent the previous lower bounds for collision resistance by constructing a simple length-preserving RO combiner $$\widetilde{C}_{\mathcal{Z}_1,\mathcal{Z}_2}^{h_1,h_2}(M) = h_1(M, \mathcal{Z}_1) \oplus h_2(M, \mathcal{Z}_2),$$ where $\mathcal{Z}_1, \mathcal{Z}_2$ are random salts of appropriate length. We show that this extra randomness is necessary for RO combiners, and indeed our construction is somewhat tight with this lower bound.
On the negative side, we show that one cannot generically apply the composition theorem to further replace "monolithic" hashes $h_1$ and $h_2$ by some simpler indifferentiable construction (such as the Merkle-Damgård transformation) from smaller components, such as fixed-length compression functions. Despite this issue, we directly prove collision resistance of the Merkle-Damgård variant of our combiner, where $h_1$ and $h_2$ are replaced by iterative Merkle-Damgård hashes applied to fixed-length compression functions. Thus, we can still subvert the concatenation barrier for collision-resistance combiners using practically small components.
Ehud Aharoni, Nir Drucker, Gilad Ezov, Eyal Kushnir, Hayim Shaul, Omri Soceanu
Alishah Chator, Matthew Green, Pratyush Ranjan Tiwari
Mojtaba Bisheh Niasar, Daniel Lo, Anjana Parthasarathy, Blake Pelton, Bharat Pillilli, Bryan Kelly
Rasheed Kibria, Farimah Farahmandi, Mark Tehranipoor
Boris Ryabko
Eliana Carozza, Geoffroy Couteau, Antoine Joux
The analysis of our construction is non-trivial and forms a core technical contribution of our work. It requires careful combinatorial analysis and combines several new ideas, such as analyzing soundness in a relaxed setting where a cheating prover is allowed to use any witness sufficiently close to a regular vector. We complement our analysis with an in-depth overview of existing attacks against RSD.
Our signatures are competitive with the best-known code-based signatures, ranging from $12.52$ KB (fast setting, with a signing time of the order of a few milliseconds on a single core of a standard laptop) to about $9$ KB (short setting, with estimated signing time of the order of 15ms).
Rujia Li, Xuanwei Hu, Qin Wang, Sisi Duan, Qi Wang
Pawel Cyprys, Shlomi Dolev, Oded Margalit
In order to enhance the security of our approach, we propose the integration of a secret-sharing scheme based on a linear polynomial. This helps mitigate collisions and adds an additional layer of perfect security. We thoroughly investigate the interactions between different aspects of one-way functions to strengthen the reliability of commitments. Lastly, we explore the possibility of nesting one-way functions as a countermeasure against potential backdoors.
Through our study, we aim to contribute to the advancement of secure encryption techniques by leveraging the inherent strengths of the one-time pad and carefully considering the interplay of various components in the design of one-way functions.
Tim Dokchitser, Alexandr Bulkin
04 July 2023
Chair of IT Security at the Brandenburg University of Technology Cottbus-Senftenberg
Candidates must hold a Master’s degree or equivalent in Computer Science or related disciplines, or be close to completing it. If you are interested, please send your CV, transcript of records from your Master studies, and an electronic version of your Master's thesis (if possible), as a single pdf file. The positions will remain open until they are filled.
Closing date for applications:
Contact: Ivan Pryvalov (ivan.pryvalov@b-tu.de)
Aarhus University Crypto Group, Denmark
Closing date for applications:
Contact: Sophia Yakoubov (sophia.yakoubov@cs.au.dk)
Leuven, Belgium, 25 March - 29 March 2024
03 July 2023
SUTD, Singapore
We are looking for postdocs / research fellows with expertise on cybersecurity in general and CPS security in particular. The candidates should meet the following requirements.
Fresh PhD graduates are welcome to apply. Only short-listed candidates will be contacted for interview. Successful candidates will be offered internationally competitive remuneration. Interested candidates please send your CV to Prof. Jianying Zhou.
Closing date for applications:
Contact: Prof. Jianying Zhou [jianying_zhou@sutd.edu.sg]