Fast Cloud-RSA Scheme for Promoting Data Confidentiality in the Cloud Computing

Confidentiality is among the most important obstacles for widespread adoption of cloud services. In fact, researchers have invented a new promising form of encryption, homomorphic encryption, that can be considered as an effective way to overcome these obstacles. Since cloud computing environment is more threatened by attacks and since cloud consumers often use resource-constrained devices to access to cloud computing services, the homomorphic encryption schemes must be promoted, in terms of security level and running time, to work efficiently. At EMENA-TSSL'16, we boosted the standard RSA encryption scheme at security level, Cloud-RSA. In this paper, we propose a new fast variant of the Cloud-RSA scheme to speed up its algorithms. The proposed variant uses a modulus of the form N = prqs for r, s ≥ 2 and employs Hensel lifting and Chinese remaindering to decrypt. Simulation results show that the proposed variant gives a large speed up over the Cloud-RSA scheme while preserving a prescribed security level.