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A tight bound for exhaustive key search attacks against Message Authentication Codes

Vinícius G. P. de SÁ, Davidson R. Boccardo, Luiz Fernando Rust, Raphael C. S. Machado (2013)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

A Message Authentication Code (MAC) is a function that takes a message and a key as parameters and outputs an authentication of the message. MAC are used to guarantee the legitimacy of messages exchanged through a network, since generating a correct authentication requires the knowledge of the key defined secretly by trusted parties. However, an attacker with access to a sufficiently large number of message/authentication pairs may use a brute force algorithm to infer the secret key: from a set...

Deciding knowledge in security protocols under some e-voting theories

Mouhebeddine Berrima, Narjes Ben Rajeb, Véronique Cortier (2011)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

In the last decade, formal methods have proved their interest when analyzing security protocols. Security protocols require in particular to reason about the attacker knowledge. Two standard notions are often considered in formal approaches: deducibility and indistinguishability relations. The first notion states whether an attacker can learn the value of a secret, while the latter states whether an attacker can notice some difference between protocol runs with different values of the secret. Several...

Deciding knowledge in security protocols under some e-voting theories

Mouhebeddine Berrima, Narjes Ben Rajeb, Véronique Cortier (2011)

RAIRO - Theoretical Informatics and Applications

In the last decade, formal methods have proved their interest when analyzing security protocols. Security protocols require in particular to reason about the attacker knowledge. Two standard notions are often considered in formal approaches: deducibility and indistinguishability relations. The first notion states whether an attacker can learn the value of a secret, while the latter states whether an attacker can notice some difference between protocol runs with different values of the secret. Several...

Improving the Watermarking Process with Usage of Block Error-Correcting Codes

Berger, Thierry, Todorov, Todor (2008)

Serdica Journal of Computing

The emergence of digital imaging and of digital networks has made duplication of original artwork easier. Watermarking techniques, also referred to as digital signature, sign images by introducing changes that are imperceptible to the human eye but easily recoverable by a computer program. Usage of error correcting codes is one of the good choices in order to correct possible errors when extracting the signature. In this paper, we present a scheme of error correction based on a combination of Reed-Solomon...

On Graph-Based Cryptography and Symbolic Computations

V. A., Ustimenko (2007)

Serdica Journal of Computing

We have been investigating the cryptographical properties of in nite families of simple graphs of large girth with the special colouring of vertices during the last 10 years. Such families can be used for the development of cryptographical algorithms (on symmetric or public key modes) and turbocodes in error correction theory. Only few families of simple graphs of large unbounded girth and arbitrarily large degree are known. The paper is devoted to the more general theory of directed graphs of large...

On the anti–synchronization detection for the generalized Lorenz system and its applications to secure encryption

Volodymyr Lynnyk, Sergej Čelikovský (2010)

Kybernetika

In this paper, a modified version of the Chaos Shift Keying (CSK) scheme for secure encryption and decryption of data will be discussed. The classical CSK method determines the correct value of binary signal through checking which initially unsynchronized system is getting synchronized. On the contrary, the new anti-synchronization CSK (ACSK) scheme determines the wrong value of binary signal through checking which already synchronized system is loosing synchronization. The ACSK scheme is implemented...

Sender-equivocable encryption schemes secure against chosen-ciphertext attacks revisited

Zhengan Huang, Shengli Liu, Baodong Qin, Kefei Chen (2015)

International Journal of Applied Mathematics and Computer Science

Fehr et al. (2010) proposed the first sender-equivocable encryption scheme secure against chosen-ciphertext attacks (NCCCA) and proved that NC-CCA security implies security against selective opening chosen-ciphertext attacks (SO-CCA). The NC-CCA security proof of the scheme relies on security against substitution attacks of a new primitive, the “crossauthentication code”. However, the security of the cross-authentication code cannot be guaranteed when all the keys used in the code are exposed. Our...

Sensitivity of computer support game algorithms of safe ship control

Józef Lisowski (2013)

International Journal of Applied Mathematics and Computer Science

The paper investigates the sensitivity of safe ship control to inaccurate data from the ARPA anti-collision radar system and to changes in the process control parameters. The system structure of safe ship control in collision situations and computer support programmes exploring information from the ARPA anti-collision radar are presented. Sensitivity characteristics of the multistage positional non-cooperative and cooperative game and kinematics optimization control algorithms are determined through...

The accessibility of an access structure

Francesc Carreras, Antonio Magaña, Carlo Munuera (2006)

RAIRO - Theoretical Informatics and Applications

In secret sharing, different access structures have different difficulty degrees for acceding to the secret. We give a numerical measure of how easy or how difficult is to recover the secret, depending only on the structure itself and not on the particular scheme used for realizing it. We derive some consequences.

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