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Об одном алгоритме проверки существования подквазигрупп
Quasigroup-based cryptoalgorithms are being actively studied in the framework of theoreticprojects; besides that, a number of quasigroup-based algorithms took part in NIST contestsfor selection of cryptographic standards. From the viewpoint of security it is highly desirableto use quasigroups without proper subquasigroups (otherwise transformations can degrade).We propose algorithms that take a quasigroup specified by the Cayley table as the input anddecide whether there exist proper subquasigroups or subquasigroups of the order at least 2.Temporal complexity of the algorithms is optimized at the cost of increased spatial complexity.We prove bounds on time and memory and analyze the efficiency of software implementationsapplied to quasigroups of a large order. The results were reported at the XVIII InternationalConference «Algebra, Number Theory and Discrete Geometry: modern problems, applicationsand problems of history».