A Visual Cryptographic Technique for Transferring Secret Image in Public Cloud
Ashok Kumar J1, Gopinath Ganapathy2

1Ashok Kumar J, Research Scholar, Bharathidasan University, Engineering and Applications, School of Computer Science, Tiruchirappalli, Tamil Nadu, India.
2Dr. Gopinath Ganapathy, Registrar, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India.
Manuscript received on December 16, 2019. | Revised Manuscript received on December 24, 2019. | Manuscript published on January 10, 2020. | PP: 2257-2260 | Volume-9 Issue-3, January 2020. | Retrieval Number: C9037019320/2020©BEIESP | DOI: 10.35940/ijitee.C9037.019320
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: The use of “Asymmetric Cryptography” provides the way to avail the feature of non-repudiation, encryption of data and defining the user digital identity to map with the authenticating user in the Public Cloud. A security technique is to be provided for the data even before it is stored on the Cloud. The public key certificate can be transferred into key server for encrypting the data by other users or devices in the public cloud. By using OpenPGP standard (PGP)/GNU Privacy Guard (GnuPG), public key certificate and the private key certificate can be generated by the user in the client system itself. The client private key can never be moved out from the client system and users only responsibility is to decrypt their data like images. This methodology will be very much suitable for authenticating, transferring, accessing and storing the images in the Public Cloud. The computational cost for encrypting the whole image with public key will be huge and so the hybrid methodology is proposed with visual cryptography technique and Elliptic-Curve Diffie–Hellman (ECDH) methodology. This paper proposes secure transfer of secret image by using visual cryptography technique and thereby modifying any one of the visual shares into encrypted data with ECDH secret key and finally converted those two shares into base64 format. The proposed algorithm is implemented by using the Python language and their results are discussed with sample images. 
Keywords: Cloud Storage, Elliptic Curve Cryptography, ECDH, Visual Cryptography.
Scope of the Article: Cryptography and Applied Mathematics