Stefano Barbero

activity

20112026

most citedPeriodic representations for cubic irrationalities

9 citations · 50 across the 24 of their papers we have counts for

collaborators

Showing 2020Show all

4 papers · 1 filter

math.CO2020

Rotational analysis of ChaCha permutation

Stefano Barbero, Emanuele Bellini, Rusydi Makarim

We show that the underlying permutation of ChaCha20 stream cipher does not behave as a random permutation for up to 17 rounds with respect to rotational cryptanalysis. In particula…

math.NT2020

An isomorphism between the convolution product and the componentwise sum connected to the D'Arcais numbers and the Ramanujan tau function

Stefano Barbero, Umberto Cerruti, Nadir Murru

Given a commutative ring $R$ with identity, let $H_{R}$ be the set of sequences of elements in $R$ . We investigate a novel isomorphism between $(H_{R}, +)$ and $(H ~_{R}, *)$ , where…

math.NT2020

Approximations of algebraic irrationalities with matrices

Stefano Barbero, Umberto Cerruti, Nadir Murru

We discuss the use of matrices for providing sequences of rationals that approximate algebraic irrationalities. In particular, we study the regular representation of algebraic exte…

math.NT2020

Linear fractional transformations and non-linear leaping convergents of some continued fractions

Christopher Havens, Stefano Barbero, Umberto Cerruti +1

For $α_{0} = [a_{0}, a_{1}, \dots]$ an infinite continued fraction and $σ$ a linear fractional transformation, we study the continued fraction expansion of $σ (α_{0})$ and its c…