Cryptanalysis of a One-Time Code-Based Digital Signature Scheme

We consider a one-time digital signature scheme recently proposed by Persichetti and show that a successful key recovery attack can be mounted with limited complexity. The attack we propose exploits a single signature intercepted by the attacker, and relies on a statistical analysis performed over such a signature, followed by information set decoding. We assess the attack complexity and show that a full recovery of the secret key can be performed with a work factor that is far below the claimed security level. The efficiency of the attack is motivated by the sparsity of the signature, which leads to a significant information leakage about the secret key.Comment: 5 pages, 1 figur

The Behaviour of the Dollar and Exchange Rates in Europe: Empirical Evidence and Possible Explanations

The analysis of the day-by-day evolution of currency markets often emphasises the relationship between the behaviour of the US dollar and that of the exchange rates between the other major currencies, in particular the tendency of EMS currencies to appreciate vis-à-vis the DM in periods of dollar strength. In this paper we systematically analyse this relationship. In particular, we examine the extent to which it has changed in the last ten years, a span of time that included a period without realignments in the EMS, the crisis of the System, the suspension of the lira’s participation in the ERM and the withdrawal of the pound, the “widened” band for the other currencies, and the re-entry of the lira. We also suggest a possible explanation for this relationship and find supporting empirical evidence for it: we show that the reactions of each bilateral exchange rate to shocks to the value of the dollar are related to the different orientation of monetary and exchange-rate policies in the various European countries, and that these differences are consistent with the potential effects of variations in the exchange rates vis-à-vis the dollar and the DM on each country’s rate of inflation.exchange rate, Europe, fundamentals, forecast

Life at the end of life: beliefs about individual life after death and "good death" models - a qualitative study

BACKGROUND: Different ideas of "good death" may influence the effectiveness of end-of-life care in patients with different ethos. This study aimed to identify the influence of believing in individual life after death on "good death" models. METHODS: Semi structured-interview to 8 persons, 4 believers and 4 non-believers in individual life after death from the general Italian population. Analysis of the transcribed text according to the method suggested by Mc Cracken. RESULTS: The analysis has shown a diverse and coherent conceptualization of death according to whether the subjects believe or not in individual life after death. Believers, for whom death marks the passage to a new dimension, prefer to be unaware of dying, while non-believers, for whom death is the end of the individual, prefer to be conscious until the very end of life. However some important aspects in common have been identified, i.e. having close people nearby, receiving assistance from experts, or the preference for a soft atmosphere around the dying person. CONCLUSION: There are aspects in common and aspects in contrast between believers and non-believers in individual life after death: while sharing many aspects of what a "good death" ought to be, they have opposite stands on being aware of dying. A plurality of models should be foreseen, accepting, in this case, their practical and theoretical implications

The Feynman problem and Fermionic entanglement: Fermionic theory versus qubit theory

The present paper is both a review on the Feynman problem, and an original research presentation on the relations between Fermionic theories and qubits theories, both regarded in the novel framework of operational probabilistic theories. The most relevant results about the Feynman problem of simulating Fermions with qubits are reviewed, and in the light of the new original results the problem is solved. The answer is twofold. On the computational side the two theories are equivalent, as shown by Bravyi and Kitaev (Ann. Phys. 298.1 (2002): 210-226). On the operational side the quantum theory of qubits and the quantum theory of Fermions are different, mostly in the notion of locality, with striking consequences on entanglement. Thus the emulation does not respect locality, as it was suspected by Feynman (Int. J. Theor. Phys. 21.6 (1982): 467-488).Comment: 46 pages, review about the "Feynman problem". Fixed many typo