Panagiotis Rizomiliotis

Security analysis of the song-mitchell authentication protocol for low-cost RFID tags

In this paper, we describe an attack against one of the most efficient authentication protocols for low-cost RFID tags recently proposed by Song and Mitchell. A weak attacker, i.e. an attacker that has no access to the internal data of a tag, is able to impersonate a legitimate reader/server, and to desynchronize a tag. The attack is very efficient and has minimal computational complexity. Finally, we propose a simple solution to fix the flaw.

On the Resistance of Boolean Functions Against Algebraic Attacks Using Univariate Polynomial Representation

In the past few years, algebraic attacks against stream ciphers with linear feedback function have been significantly improved. As a response to the new attacks, the notion of algebraic immunity of a Boolean function f was introduced, defined as the minimum degree of the annihilators of f and f + 1. An annihilator of f is a nonzero Boolean function g , such that f · g = 0. While several constructions of Boolean functions with optimal algebraic immunity have been proposed, there is no significant progress concerning the resistance against the so-called fast algebraic attacks. In this paper, we provide a framework to assess the resistance of Boolean functions against the new algebraic attacks, including fast algebraic attacks. The analysis is based on the univariate polynomial representation of Boolean functions and necessary and sufficient conditions are presented for a Boolean function to have optimal behavior against all the new algebraic attacks. Finally, we introduce a new infinite family of balanced Boolean functions described by their univariate polynomial representation. By applying the new framework, we prove that all the members of the family have optimal algebraic immunity and we efficiently evaluate their behavior against fast algebraic attacks.

Feedback Phase in Optically Generated Chaos: A Secret Key for Cryptographic Applications

The feedback phase in a chaotic system consisting of a semiconductor laser subject to delayed optical feedback is considered for the first time as a secret key for secure chaotic communications not exclusively based on hardware uniqueness. Extensive numerical simulations illustrate that the feedback phase is of extreme importance as far as synchronization is concerned. The ability of an eavesdropper to attack the intensity-modulated message when a pseudorandom variation of the feedback phase is imposed at the transmitters side is numerically quantified by bit-error-rate calculations. The analysis demonstrates that the eavesdropper is not able to synchronize and hence to extract the message when he is not aware of the phase variations even if he is equipped with an identical chaotic device.

Cryptography Goes to the Cloud

In this paper we identify some areas where cryptography can help a rapid adoption of cloud computing. Although secure storage has already captured the attention of many cloud providers, offering a higher level of protection for their customer’s data, we think that more advanced techniques such as searchable encryption and secure outsourced computation will become popular in the near future, opening the doors of the Cloud to customers with higher security requirements.

On the quadratic span of binary sequences

The problem of finding the shortest feedback shift register, with quadratic feedback function that generates a given finite-length sequence is considered. An algorithm for the determination of the quadratic span and the feedback function, which takes advantage of the special block structure of the associated system of linear equations, is proposed.

Minimum linear span approximation of binary sequences

The determination of the minimum linear span sequence that differs from a given binary sequence, of period N=2/sup n/-1, by at most one digit is discussed and three methods are presented: the sequential divisions method, the congruential equations method, and the phase synchronization method. High-level algorithm organizations are provided. Finally, guidelines on sequence characterization and design via the notion of robustness are given.

GHB # : a provably secure HB-like lightweight authentication protocol

RFID technology constitutes a fundamental part of what is known as the Internet of Things; i.e. accessible and interconnected machines and everyday objects that form a dynamic and complex environment. In order to secure RFID tags in a cost-efficient manner, the last few years several lightweight cryptography-based tag management protocols have been proposed. One of the most promising proposals is the

Relay selection for secure 5G green communications

\textit{HB}^{+}

New Constructions of High-Performance Low-Complexity Convolutional Codes

protocol, a lightweight authentication protocol that is supported by an elegant security proof against all passive and a subclass of active attackers based on the hardness of the Learning Parity with Noise (LPN) problem. However, the

How to protect security and privacy in the IoT: a policy-based RFID tag management protocol

\textit{HB}^{+}