Analysis of Cloud Databases by Using Adaptive Encryption Algorithm

Abstract

The cloud database as a service is a novel paradigm that can support several Internet-based applications, but its adoption requires the solution of information confidentiality problems. We propose a novel architecture for adaptive encryption of public cloud databases that offers an interesting alternative to the trade-off between the required data confidentiality level and the flexibility of the cloud database structures at design time. We demonstrate the feasibility and performance of the proposed solution through a software prototype. Moreover, we propose an original cost model that is oriented to the evaluation of cloud database services in plain and encrypted instances and that takes into account the variability of cloud prices and tenant workload during a medium-term period. The proposed architecture guarantees in an adaptive way the best level of data confidentiality for any database workload, even when the set of SQL queries dynamically changes. The adaptive encryption scheme, which was initially proposed for applications not referring to the cloud, encrypts each plain column into multiple encrypted columns, and each value is encapsulated into different layers of encryption, so that the outer layers guarantee higher confidentiality but support fewer computation capabilities with respect to the inner layers. we propose the first analytical cost estimation model for evaluating cloud database costs in plain and encrypted instances from a tenant’s point of view in a medium-term period. It takes also into account the variability of cloud prices and the possibility that the database workload may change during the evaluation period.
Key words: Cloud Database; Confidentiality; Encryption; Adaptively; Cost Estimation Model