66 research outputs found
On the Evolution of Boomerang Uniformity in Cryptographic S-boxes
S-boxes are an important primitive that help cryptographic algorithms to be
resilient against various attacks. The resilience against specific attacks can
be connected with a certain property of an S-box, and the better the property
value, the more secure the algorithm. One example of such a property is called
boomerang uniformity, which helps to be resilient against boomerang attacks.
How to construct S-boxes with good boomerang uniformity is not always clear.
There are algebraic techniques that can result in good boomerang uniformity,
but the results are still rare. In this work, we explore the evolution of
S-boxes with good values of boomerang uniformity. We consider three different
encodings and five S-box sizes. For sizes and , we
manage to obtain optimal solutions. For , we obtain optimal
boomerang uniformity for the non-APN function. For larger sizes, the results
indicate the problem to be very difficult (even more difficult than evolving
differential uniformity, which can be considered a well-researched problem).Comment: 15 pages, 3 figures, 4 table
Variation of vascular ring as a cause of extubation failure
We report on an unexpected extubation failure in a two year old boy. In our patient, failure of extubation led to a diagnostic examination. The result of our examination was discovery of a congenital anomaly of the aortic arch and great vessels (vascular ring) with compression of the trachea. The presence of this anomaly in this patient was unknown to us before. A successful surgical procedure eliminated the underlying cause of the persistent extubation failures
A characterisation of S-box fitness landscapes in cryptography
Substitution Boxes (S-boxes) are nonlinear objects often used in the design
of cryptographic algorithms. The design of high quality S-boxes is an
interesting problem that attracts a lot of attention. Many attempts have been
made in recent years to use heuristics to design S-boxes, but the results were
often far from the previously known best obtained ones. Unfortunately, most of
the effort went into exploring different algorithms and fitness functions while
little attention has been given to the understanding why this problem is so
difficult for heuristics. In this paper, we conduct a fitness landscape
analysis to better understand why this problem can be difficult. Among other,
we find that almost each initial starting point has its own local optimum, even
though the networks are highly interconnected
Variation of vascular ring as a cause of extubation failure
We report on an unexpected extubation failure in a two year old boy. In our patient, failure of extubation led to a diagnostic examination. The result of our examination was discovery of a congenital anomaly of the aortic arch and great vessels (vascular ring) with compression of the trachea. The presence of this anomaly in this patient was unknown to us before. A successful surgical procedure eliminated the underlying cause of the persistent extubation failures
Cloud engineering is search based software engineering too
Many of the problems posed by the migration of computation to cloud platforms can be formulated and solved using techniques associated with Search Based Software Engineering (SBSE). Much of cloud software engineering involves problems of optimisation: performance, allocation, assignment and the dynamic balancing of resources to achieve pragmatic trade-offs between many competing technical and business objectives. SBSE is concerned with the application of computational search and optimisation to solve precisely these kinds of software engineering challenges. Interest in both cloud computing and SBSE has grown rapidly in the past five years, yet there has been little work on SBSE as a means of addressing cloud computing challenges. Like many computationally demanding activities, SBSE has the potential to benefit from the cloud; âSBSE in the cloudâ. However, this paper focuses, instead, of the ways in which SBSE can benefit cloud computing. It thus develops the theme of âSBSE for the cloudâ, formulating cloud computing challenges in ways that can be addressed using SBSE
From fitness landscape to crossover operator choice
Contains fulltext :
132817.pdf (publisher's version ) (Open Access
- âŠ