Tytarchuk Y. Protection of personal information of users of computer systems which use public cloud services

In the dissertation work was set and solved the urgent task of increasing the efficiency of information security in computer systems, using in its structure public cloud services, is based on the development and implementation of new methods and means of encryption. The method of protecting the information of users in a computer system containing the public cloud computing services, based on a partially homomorphic encryption algorithm, that’s allowed to perform calculations in public cloud service without disclosing private user information is developed. The criterion of efficiency of the partially homomorphic encryption algorithm is determined. A theoretically substantiated modification of the encryption method on the basis of elliptic curves was developed in order to provide to it homomorphic properties with respect to the addition operation. A mathematical model of a computer system with limited access to the information processed in it from the side of the provider of cloud service with the use of partially homomorphic encryption algorithm on the basis of elliptic curves is developed. A method for decoding numbers encoded by points of an elliptic curve is developed. The method of creation of systems aimed at protecting private information of users by the transformation of the computing model with the purpose of using algorithms of partial or fully homomorphic encryption is developed. Software was implemented that uses computational procedures for partially homomorphic encryption based on elliptic curves using computing power of technical means.