Organization of a secure query to a database in the cloud

The development of cloud computing, including the storage and processing of confidential user data on servers that can be attacked, puts forward new requirements for information protection. The article explores the problem of obtaining information from the database by the client in such a way that no one except the client himself get any information about the information the client is interested in (PIR - Private Information Retrieval). The problem was introduced in 1995 by Chor, Goldreich, Kushilevitz and Sudan in the information-theoretic setting. A model of cloud computing is proposed. It includes a cloud, a user, clients, a trusted dealer, a passive adversary in the cloud. Also, the attacking side has the ability to create fake clients to generate an unlimited number of requests. An algorithm for the organization and database distribution on the cloud and an algorithm for obtaining the required bit were proposed. Communication complexity of the algorithm was estimated. The probability of revealing required bit's number in the case when fake clients perform unlimited requests was estimated too.