One-Way Functions and Composition of Conjugacy and Discrete Logarithm Problems in the Small Cancellation Groups

• Main Author: N. V. Bezverkhniy
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2015-01-01
• Series: Matematika i Matematičeskoe Modelirovanie
• Subjects: one-way functions; small cancellation conditions; diagrams in groups; membership problem for cyclic subgroups
• Online Access: http://mathm.elpub.ru/jour/article/view/32

<p>The paper considers the possibility for building a one-way function in the small cancellation group. Thus, it uses the algorithm to solve the problem for a cyclic subgroup, also known as a discrete logarithm problem, and the algorithm to solve the word problem in this class of groups.</p><p>Research is conducted using geometric methods of combinatorial group theory (the method of diagrams in groups).</p><p>In public channel exchange of information are used one-way functions, direct calculation of which should be much less complicated than the calculation of the inverse function. The paper considers the combination of two problems: discrete logarithms and conjugacy. This leads to the problem of conjugate membership for a cyclic subgroup. The work proposes an algorithm based on this problem, which can be used as a basis in investigation of the appropriate one-way function for its fitness to build a public key distribution scheme.</p><p>The study used doughnut charts of word conjugacy, and for one special class of such charts has been proven a property of the layer-based periodicity. The presence of such properties is obviously leads to a solution of the power conjugacy of words in the considered class of groups. Unfortunately, this study failed to show any periodicity of a doughnut chart, but for one of two possible classes this periodicity has been proven.</p><p>The building process of one-way function considered in the paper was studied in terms of possibility to calculate both direct and inverse mappings. The computational complexity was not considered. Thus, the following two tasks were yet unresolved: determining the quality of one-way function in the above protocol of the public key distribution and completing the study of the periodicity of doughnut charts of word conjugacy, leading to a positive solution of the power conjugacy of words in the class groups under consideration.</p>