Int. J. Information and Computer Security, Vol. 11, No. 1, 2019 1 Copyright © 2019 Inderscience Enterprises Ltd. MONcrypt: a technique to ensure the confidentiality of outsourced data in cloud storage S.S. Manikandasaran* Christhuraj Institute of Computer Application, Christhu Raj College, Trichy, India Email: moni.tamil@gmail.com *Corresponding author L. Arockiam Department of Computer Science, St. Joseph’s College, College Road, Tiruchirappalli, Tamil Nadu – 620002, India Email: larockiam@yahoo.co.in P.D. Sheba Kezia Malarchelvi Department of Computer Science and Engineering, J. J. College of Engineering and Technology, Ammapettai, Tiruchirappalli, Tamil Nadu – 620009, India Email: pdsheba@yahoo.co.in Abstract: Cloud provides storage for enterprises to store their data in virtual storage. Enterprises outsourced their data but security of data in cloud storage is not guaranteed. If anything wrong happens on the data, the users suspect the cloud storage providers. Ensuring the confidentiality of outsourced data plays a vital role in the cloud security. To ensure the confidentiality of outsourced data, this paper proposes a technique called MONcrypt. MONcrypt is based on obfuscation technique. Obfuscation is a process of masking the original text into irrelevant text without using any key unlike encryption. MONcrypt uses key for de-obfuscation. This novel obfuscation technique is used to ensure the confidentiality of outsourced data in cloud storage. The paper compares the proposed technique with existing technique like Base32, Base64, hexadecimal encoding, DES, 3DES and Blowfish. The proposed technique shows better performance and security compared with the existing techniques. Keywords: data outsourcing; confidentiality; cloud storage; obfuscation; security. Reference to this paper should be made as follows: Manikandasaran, S.S., Arockiam, L. and Malarchelvi, P.D.S.K. (2019) ‘MONcrypt: a technique to ensure the confidentiality of outsourced data in cloud storage’, Int. J. Information and Computer Security, Vol. 11, No. 1, pp.1–16.