325 research outputs found
On formal verification of arithmetic-based cryptographic primitives
Cryptographic primitives are fundamental for information security: they are
used as basic components for cryptographic protocols or public-key
cryptosystems. In many cases, their security proofs consist in showing that
they are reducible to computationally hard problems. Those reductions can be
subtle and tedious, and thus not easily checkable. On top of the proof
assistant Coq, we had implemented in previous work a toolbox for writing and
checking game-based security proofs of cryptographic primitives. In this paper
we describe its extension with number-theoretic capabilities so that it is now
possible to write and check arithmetic-based cryptographic primitives in our
toolbox. We illustrate our work by machine checking the game-based proofs of
unpredictability of the pseudo-random bit generator of Blum, Blum and Shub, and
semantic security of the public-key cryptographic scheme of Goldwasser and
Micali.Comment: 13 page
Authenticated key agreement mediated by a proxy re-encryptor for the Internet of Things
International audienceThe Internet of Things (IoT) is composed of a wide range of heterogeneous network devices that communicate with their users and the surrounding devices. The secure communications between these devices are still essential even with little or no previous knowledge about each other and regardless of their resource capabilities. This particular context requires appropriate security mechanisms which should be wellsuited for the heterogeneous nature of IoT devices, without pre-sharing a secret key for each secure connection. In this work, we first propose a novel symmetric cipher proxy re-encryption scheme. Such a primitive allows a user to delegate her decryption rights to another with the help of a semi-trusted proxy, but without giving this latter any information on the transmitted messages and the user's secret keys. We then propose AKAPR, an Authenticated Key Agreement mediated by a Proxy Re-encryptor for IoT. The mechanism permits any two highly resource-constrained devices to establish a secure communication with no prior trust relationship. AKAPR is built upon our proposed proxy re-encryption scheme. It has been proved by ProVerif to provide mutual authentication for participants while preserving the secrecy of the generated session key. In addition, the scheme benefits from the lightness of our proxy re-encryption algorithm as it requires no expensive cryptographic operations such as pairing or modular exponentiatio
Conflict Optimization for Binary CSP Applied to Minimum Partition into Plane Subgraphs and Graph Coloring
CG:SHOP is an annual geometric optimization challenge and the 2022 edition
proposed the problem of coloring a certain geometric graph defined by line
segments. Surprisingly, the top three teams used the same technique, called
conflict optimization. This technique has been introduced in the 2021 edition
of the challenge, to solve a coordinated motion planning problem. In this
paper, we present the technique in the more general framework of binary
constraint satisfaction problems (binary CSP). Then, the top three teams
describe their different implementations of the same underlying strategy. We
evaluate the performance of those implementations to vertex color not only
geometric graphs, but also other types of graphs.Comment: To appear at ACM Journal of Experimental Algorithmic
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Identification of Streptococcus suis Meningitis through Population-Based Surveillance, Togo, 2010-2014.
During 2010-2014, we enrolled 511 patients with suspected bacterial meningitis into surveillance in 2 districts of northern Togo. We identified 15 persons with Streptococcus suis infection; 10 had occupational contact with pigs, and 12 suffered neurologic sequelae. S. suis testing should be considered in rural areas of the African meningitis belt
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Relationship Between Biogenic Amines and Free Amino Acid Contents of Winesand Musts from Alentejo (Portugal)
The concentration of biogenic amines and free amino acids was studied in 102
Portuguese wines and 18 musts from Alentejo demarcated (D.O.C.) regions. Most wines
were commercial, except for 38 monovarietals obtained by micro vinification. Musts
from the varieties used to produce the latter wines were also studied. Both biogenic
amines and free amino acids were analyzed by HPLC using fluorescence detection for
their o-phthalaldehyde/fluorenylmethyl chloroformate (OPA/FMOC) derivatives. The
most significant amines (average 10.8 mg/L for histamine+tyramine in red, and 7.4
mg/L for white wines) were found to be present at low levels and, although no important
relationship between each individual biogenic amine could be obtained, the total amine
content depends significantly on the assimilable amino acid content in wine
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