Periodical key change for cloud mutable security protocol

Abstract

Securing cloud databases is a challenge in the cloud computing paradigm. Several research studies have been conducted to improve the security level in cloud computing. Many security schemes do not preserve mathematical or logical operations over encrypted data. Order Preserving Encryption schemes (OPEs) preserve the ordering (logical) operations over encrypted data. However, many OPE schemes leak information. Mutable Order Preserving Encoding (MOPE) algorithm achieves ideal security when it uses Randomized Encryption (RND) rather than Deterministic Encryption (DET) Scheme. RND and DET can be implemented with any standard cipher such as AES. This research proposes to use DET for MOPE and achieves the same security level when it uses RND. This paper proposes to change the encryption key on a certain time or a certain number of transactions. MOPE keeps its search tree balanced on each transaction applied by the system to maintain the performance. To enhance the security level without degrading the performance, this paper is utilizing the time consumed by rebalancing part of the tree in MOPE algorithm. This paper finds an optimal window to change the encryption key with an acceptable loss of performance.