In this paper, we revisit the famous Davies-Murphy cryptanalysis of DES. First we improve its complexity down to the analysis of 2 chosen plaintexts, by considering 6 distributions instead of 7. The previous improvement of the attack by Biham and Biryukov costed 2 known plaintexts. This new result is better than differential cryptanalysis but slightly worse than linear cryptanalysis. Secondly, ...

Background: Behaviour management techniques [BMTs] are utilized by dentists to aid children’s dental anxiety. Children’s perceptions of these have been under-explored, and their feedback could help inform paediatric dentistry. Aim: To explore children’s acceptability and perceptions of dental communication and BMTs, and to compare these by age, gender, and dental anxiety. Design: Sixty-two 9-to...

A theorem of Besicovitch and Davies implies for Cantor space 2 that each Σ1 (analytic) class of positive Hausdorff dimension contains a Π1 (closed) subclass of positive dimension. We consider the weak (Muchnik) reducibility ≤w in connection with the mass problem S(U) of computing a set X ⊆ ω such that the Σ 1 class U of positive dimension has a Π 1 (X) subclass of positive dimension. We determi...