Analysis of reaction and timing attacks against cryptosystems based on sparse parity-check codes

In this paper we study reaction and timing attacks against cryptosystems based on sparse parity-check codes, which encompass low-density parity-check (LDPC) codes and moderate-density parity-check (MDPC) codes. We show that the feasibility of these attacks is not strictly associated to the quasi-cyclic (QC) structure of the code but is related to the intrinsically probabilistic decoding of any sparse parity-check code. So, these attacks not only work against QC codes, but can be generalized to broader classes of codes. We provide a novel algorithm that, in the case of a QC code, allows recovering a larger amount of information than that retrievable through existing attacks and we use this algorithm to characterize new side-channel information leakages. We devise a theoretical model for the decoder that describes and justifies our results. Numerical simulations are provided that confirm the effectiveness of our approach

LEDAkem: a post-quantum key encapsulation mechanism based on QC-LDPC codes

This work presents a new code-based key encapsulation mechanism (KEM) called LEDAkem. It is built on the Niederreiter cryptosystem and relies on quasi-cyclic low-density parity-check codes as secret codes, providing high decoding speeds and compact keypairs. LEDAkem uses ephemeral keys to foil known statistical attacks, and takes advantage of a new decoding algorithm that provides faster decoding than the classical bit-flipping decoder commonly adopted in this kind of systems. The main attacks against LEDAkem are investigated, taking into account quantum speedups. Some instances of LEDAkem are designed to achieve different security levels against classical and quantum computers. Some performance figures obtained through an efficient C99 implementation of LEDAkem are provided.Comment: 21 pages, 3 table

Comparative Evaluation of Packet Classification Algorithms for Implementation on Resource Constrained Systems

This paper provides a comparative evaluation of a number of known classification algorithms that have been considered for both software and hardware implementation. Differently from other sources, the comparison has been carried out on implementations based on the same principles and design choices. Performance measurements are obtained by feeding the implemented classifiers with various traffic traces in the same test scenario. The comparison also takes into account implementation feasibility of the considered algorithms in resource constrained systems (e.g. embedded processors on special purpose network platforms). In particular, the comparison focuses on achieving a good compromise between performance, memory usage, flexibility and code portability to different target platforms

Causes of hospitalization among extra-European Union children in a large hospital of Northern Italy, in a five-year observation period

The hospitalizations of 1,239 patients aged 14 years or less and immigrated from extra-European Union countries in Italy were assessed in the 6-year period, from 1999 to 2004. The main demographic and clinical features were analyzed according to several variables, also distiguishing patients aged less than one year, from those aged 1-14 years. The introduction of a deed of indemnity law in 2001 profoundly changed the pattern of admissions and health care needs and exploitation during subsequent years, leading to a massive regularization of clandestine immigrants

Evaluation of Removed and Recycled Mineral Nutrients in Italian Commercial Persimmon Orchards

Persimmon is a typical fruit crop of the Mediterranean region and, since it is considered a minor species, little information is available on its nutrients need. In the present experiment, it was estimated the quantity of removed and recycled nutrients by Kaki Tipo and Rojo Brillante, the two main varieties of persimmon grown in Emilia-Romagna region (Po Valley, Italy). Plants from ten mature orchards were selected and harvested; organs (leaves in summer, fruits at harvest, abscissed leaves, roots and skeleton) biomass and mineral composition were determined. The yearly uptake of macronutrients was similar for the 2 varieties, accounting for (kg/ ha): N 89-91, P 10-11, K 79-91, Ca 132-162, Mg 22-26 and S 9. While K was mostly found in fruits, Ca and Mg were mainly partitioned to leaves. Among micronutrients, Mn and Fe showed the highest values (1.1–1.3 and 1.2–2.1 kg/ha, respectively), followed by B (370 g/ha), while Cu and Zn showed the smallest amounts (less 100 g/ha). Nitrogen, Ca, Mg and S were those more recycled than removed, while K showed an opposite trend; among the microelements, the annual recycled fractions of B and Mn were higher than that removed