Consulta a base de dados cifrada em computação nas nuvens

Abstract

With the dissemination and popularization of the Internet, more and more people and businesses are using cloud computing services. Among these services, there is a storage and hosting of databases in the clouds. In this context a problem arises, how to ensure the privacy and integrity of databases that are exposed to attacks. The goal of this dissertation is to propose an encryption protocol for consultations securely in encrypted databases that are stored on those servers. The main contribution of this work is to allow verification of the data encrypted and stored in databases of servers without having to decipher them. Given this problem, this paper first presents the main features of cloud computing environment. The following are the concepts of encryption and digital signatures required for the construction of the proposed protocol. Finally, we developed the formal model of the protocol and its prototype. To validate the protocol were carried out five experiments. Each experiment consists of an encrypted database and a database is not encrypted. In this case we evaluate the following metrics: execution time of a query, disk space occupied by the database and the key size used by the protocol. The results show that the performance of queries on encrypted databases is much less than the conventional bases. It was also noted that the disk space required to store the encrypted data is much larger than the unencrypted data. These results are directly related to the key size. In the experiments, the key size used was 1024 bits. This is the minimum recommended size for the encryption protocol proposed is secure. Given the disadvantages presented, we conclude that in a real environment, for example, where there are hundreds or even thousands of tables, the proposed encryption protocol should be used on tables whose security is critical, for example, tables that store: passwords , employee salaries, student grades, among others.