161 research outputs found
FAEST: algorithm specifications
No full textThis document describes and specifies the FAEST digital signature algorithm. It presents the underlying cryptographic components and specifies the building blocks used to construct the FAEST algorithm.
The design of FAEST is intended to provide security against attacks by quantum computers by relying only on information-theoretic and symmetric-key cryptographic primitives. In particular, in addition to standard PRFs and PRGs for randomness derivation, the security of FAEST is tightly linked to the security of AES128, AES192 and AES256, based on which the NIST security categories 1, 3, and 5 are defined
Simple Two-Message OT in the Explicit Isogeny Model
No full text In this work we study algebraic and generic models for group actions, and extend them to the universal composability (UC) framework of Canetti (FOCS 2001). We revisit the constructions of Duman et al. (PKC 2023) integrating the type-safe model by Zhandry (Crypto 2022), adapted to the group action setting, and formally define an algebraic action model (AAM). This model restricts the power of the adversary in a similar fashion to the algebraic group model (AGM). By imposing algebraic behaviour to the adversary and environment of the UC framework, we construct the UC-AAM. Finally, we instantiate UC-AAM with isogeny-based assumptions, in particular the CSIDH action with twists, obtaining the explicit isogeny model, UC-EI; we observe that, under certain assumptions, this model is closer to standard UC than the UC-AGM, even though there still exists an important separation. We demonstrate the utility of our definitions by proving UC-EI security for the passive-secure oblivious transfer protocol described by Lai et al. (Eurocrypt 2021), hence providing the first concretely efficient two-message isogeny-based OT protocol in the random oracle model against malicious adversaries. </p
TinyKeys: A New Approach to Efficient Multi-Party Computation
No full textsponsorship: Supported by the European Research Council under the ERC consolidators Grant Agreement N0. 615172 (HIPS), and by the BIU Center for Research in Applied Cryptography and Cyber Security in conjunction with the Israel National Cyber Bureau in the Prime Minister's Office. E. Orsini: Supported in part by ERC Advanced Grant ERC-2015-AdG-IMPaCT. P. Scholl: Supported by the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 731583 (SODA), and the Danish Independent Research Council under Grant-ID DFF-610800169 (FoCC). (European Research Council under the ERC consolidators Grant|615172, BIU Center for Research in Applied Cryptography and Cyber Security, Israel National Cyber Bureau in the Prime Minister's Office, ERC, European Union|731583, Danish Independent Research Council|DFF-610800169)status: Publishe
High-Performance Multi-party Computation for Binary Circuits Based on Oblivious Transfer
No full textsponsorship: Jesper Buus Nielsen was partially supported by the Danish National Research Foundation and the National Science Foundation of China (under the grant 61061130540) for the Sino-Danish Center for the Theory of Interactive Computation and a Sapere Aude grant from the Danish Council for Independent Research. Claudio Orlandi was supported by the European Research Council as part of the ERC project LAST. Enrique Larraia, Emmanuela Orsini, Peter Scholl, and Nigel P. Smart were supported in part by ERC Advanced Grant ERC-2010-AdG-267188-CRIPTO and by EPSRC via Grants EP/I03126X and EP/M012824. Nigel P. Smart was partially supported by Defense Advanced Research Projects Agency (DARPA) and the Air Force Research Laboratory (AFRL) under Agreement Number FA8750-11-2-0079. (Danish National Research Foundation, National Science Foundation of China|61061130540, Danish Council for Independent Research, European Research Council as part of the ERC project LAST, ERC|ERC-2010-AdG-267188-CRIPTO, EPSRC|EP/I03126X, EPSRC|EP/M012824, Defense Advanced Research Projects Agency (DARPA), Air Force Research Laboratory (AFRL)|FA8750-11-2-0079)status: Publishe
MASCOT:Faster Malicious Arithmetic Secure Computation with Oblivious Transfer
No full textWe consider the task of secure multi-party computation of arithmetic circuits over a finite field. Unlike Boolean circuits, arithmetic circuits allow natural computations on integers to be expressed easily and efficiently. In the strongest setting of malicious security with a dishonest majority - where any number of parties may deviate arbitrarily from the protocol - most existing protocols require expensive public-key cryptography for each multiplication in the preprocessing stage of the protocol, which leads to a high total cost. We present a new protocol that overcomes this limitation by using oblivious transfer to perform secure multiplications in general finite fields with reduced communication and computation. Our protocol is based on an arithmetic view of oblivious transfer, with careful consistency checks and other techniques to obtain malicious security at a cost of less than 6 times that of semi-honest security. We describe a highly optimized implementation together with experimental results for up to five parties. By making extensive use of parallelism and SSE instructions, we improve upon previous runtimes for MPC over arithmetic circuits by more than 200 times.</p
On the Shape of the General Error Locator Polynomial for Cyclic Codes
No full textGeneral error locator polynomials were introduced in 2005 as an alternative decoding for cyclic codes. We present now a conjecture on their sparsity which would imply polynomial-time decoding for all cyclic codes. A general result on the explicit form of the general error locator polynomial for all cyclic codes is given, along with several results for specific code families, providing evidence to our conjecture. From these, a theoretical justification of the sparsity of general error locator polynomials is obtained for all binary cyclic codes with t <= 2 and n<105, as well as for t=3 and n<63, except for some cases where the conjectured sparsity is proved by a computer check. Moreover, we summarize all related results, previously published, and we show how they provide further evidence to our conjecture. Finally, we discuss the link between our conjecture and the complexity of bounded-distance decoding of cyclic codes
Error Term Checking: Towards Chosen Ciphertext Security without Re-encryption
No full textstatus: Published onlin
Overdrive2k: Efficient Secure MPC over from Somewhat Homomorphic Encryption
No full textsponsorship: We thank Cyprien Delpech de Saint Guilhem for many helpful discussions. This work has been supported in part by ERC Advanced Grant ERC-2015-AdG-IMPaCT, by the Defense Advanced Research Projects Agency (DARPA) and Space and Naval Warfare Systems Center, Pacific (SSC Pacific) under contract No. N66001-15-C-4070, and by the FWO under an Odysseus project GOH9718N. (ERC Advanced Grant ERC-2015-AdG-IMPaCT, Defense Advanced Research Projects Agency (DARPA), Space and Naval Warfare Systems Center, Pacific (SSC Pacific)|N66001-15-C-4070, FWO|GOH9718N)status: Publishe
Concretely Efficient Large-Scale MPC with Active Security (or, TinyKeys for TinyOT)
No full textIn this work we develop a new theory for concretely efficient, large-scale MPC with active security. Current practical techniques are mostly in the strong setting of all-but-one corruptions, which leads to protocols that scale badly with the number of parties. To work around this issue, we consider a large-scale scenario where a small minority out of many parties is honest and design scalable, more efficient MPC protocols for this setting. Our results are achieved by introducing new techniques for information-theoretic MACs with short keys and extending the work of Hazay et al. (CRYPTO 2018), which developed new passively secure MPC protocols in the same context. We further demonstrate the usefulness of this theory in practice by analyzing the concrete communication overhead of our protocols, which improve upon the most efficient previous works
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