Differential entropy analysis of the IDEA block cipher

in Journal of Computational and Applied Mathematics (2014), 259(Part B), 561570

This paper describes a new cryptanalytic technique that combines differential cryptanalysis with Shannon entropy. We call it differential entropy (DE). The objective is to exploit the non-uniform ... [more ▼]

This paper describes a new cryptanalytic technique that combines differential cryptanalysis with Shannon entropy. We call it differential entropy (DE). The objective is to exploit the non-uniform distribution of output differences from a given mapping as a distinguishing tool in cryptanalysis. Our preferred target is the IDEA block cipher, since we detected significantly low entropy at the output of its multiplication operation. We looked to further extend this entropy analysis to larger components and for a number of rounds. We present key-recovery attacks on up to 2.5-round IDEA in the single-key model and without weak-key assumptions. [less ▲]

An alternative alpha finite element method (AαFEM) for free and forced structural vibration using triangular meshes

in Journal of Computational and Applied Mathematics (2010), 233(9), 2112-2135

An alternative alpha finite element method (AαFEM) using triangular elements is proposed that significantly improves the accuracy of the standard triangular finite elements and provides a superconvergent ... [more ▼]

An alternative alpha finite element method (AαFEM) using triangular elements is proposed that significantly improves the accuracy of the standard triangular finite elements and provides a superconvergent solution in the energy norm for the static analysis of two-dimensional solid mechanics problems. In the AαFEM, the piecewise constant strain field of linear triangular FEM models is enhanced by additional strain terms with an adjustable parameter α which results in an effectively softer stiffness formulation compared to a linear triangular element. The element is further extended to the free and forced vibration analyses of solids. Several numerical examples show that the AαFEM achieves high reliability compared to other existing elements in the literature. [less ▲]