Title: Secure file storage and retrieval in cloud

Authors: M. Thangavel; P. Varalakshmi; Mukund Murrali; K. Nithya

Addresses: Department of Information Technology, Thiagarajar College of Engineering, Madurai – 625015, Tamil Nadu, India ' Department of Computer Technology, Madras Institute of Technology, Anna University, Chennai – 600044, Tamil Nadu, India ' Department of Information Technology, Madras Institute of Technology, Anna University, Chennai – 600044, Tamil Nadu, India ' Department of Information Technology, Madras Institute of Technology, Anna University, Chennai – 600044, Tamil Nadu, India

Abstract: Security in cloud storage is an important aspect of cloud computing. In this paper, a novel multi-level encryption scheme which ensures security in cloud is introduced. In this scheme, a modified RSA (MRSA) key generation algorithm is used to generate the phase keys. The file is first subjected to encryption using MRSA with phase public keys. For secure transmission, a modified Vernam cipher (MVC) is applied to the file and stored in the cloud. Upon request, the file is obtained by applying inverse MVC followed by MRSA decryption using the phase private keys. This scheme was tested on different types of input files. The proposed algorithms protect the system from brute force attack. The MRSA's computational time is significantly less compared to the traditional RSA algorithm. Frequency and spectral analysis proves that MVC is strong and effective. Thus the new scheme ensures both confidentiality and integrity.

Keywords: cloud computing; file retrieval; file storage; RSA key generation; Vernam cipher; cloud security; phase keys; encryption; decryption; brute force attack; data confidentiality; data integrity; cryptography.

DOI: 10.1504/IJICS.2015.073025

International Journal of Information and Computer Security, 2015 Vol.7 No.2/3/4, pp.177 - 195

Accepted: 15 Jun 2015
Published online: 12 Nov 2015 *

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