Multiple Secret Sharing with Simple Image Encryption 323 Multiple Secret Sharing with Simple Image Encryption Heri Prasetyo 1 , Chih-Hsien Hsia 2 , Jing-Yi Deng 2 1 Department of Informatics, Universitas Sebelas Maret (UNS), Indonesia 2 Department of Computer Science and Information Engineering, National Ilan University, Taiwan heri.prasetyo@staff.uns.ac.id, chhsia625@gmail.com, jinee5232@gmail.com* * Corresponding Author: Chih-Hsien Hsia; E-mail: chhsia625@gmail.com DOI: 10.3966/160792642020032102002 Abstract Multiple Secret Sharing (MSS) aims to secure the image transmission by improving the ambiguity on image contents. The former (n, n)-MSS scheme generates n shared images from n secret images and reconstruct n recovered secret images from n shared images. This scheme hides the content of secret image by performing the eXclusive-OR (XOR) with specific masking coefficient. It exploits the Chinese Remainder Theorem (CRT) approach for generating the masking coefficient. However, the former scheme cannot work if n is odd. It overcomes the aforementioned problem by incorporating random image, transforming into nk encrypted secret images, and employing double masking coefficients. The presented MSS scheme utilizes an image encryption technique with simple chaotic maps for increasing the ambiguity of shared image content. The experimental results reveal that the proposed MSS method solves the problem on former MSS scheme and yields better performances. Keywords: CRT, Image encryption, Secret sharing, Simple chaotic, XOR 1 Introduction Nowadays, some confidential and secret information become handily to be distributed and transmitted over several parties via transmission channel. Some parties need to transfer some secret information using the transmission channel. Thus, image security technique becomes a very urgent to maintain the image integrity and information consistency. Many studies have been proposed to hide and render secret information into digital imaging media such as secret sharing [1-7], image watermarking [8], reversible data hiding [9-11], image encryption [12], etc. Among of them, the secret sharing transfers several secret images by firstly destroying the content of secret images. It has been proved effectively to transmit several secret images with the constraint of hiding the secret image content. Several attempts have been devoted to propose a new technique for Multiple Secret Sharing (MSS) task such as [1-7]. Some of them have tried to improve the performance of MSS scheme. For example, the former schemes [1-2] extended the usability of MSS scheme for grayscale image. It broads the usability and performance of the other schemes [3-6] which are only limited for the grayscale secret images. Whereas, the former scheme [7] and proposed method develop the MSS system for color images. The former schemes [3- 6] use (t, n)-threshold scenario, whereas the other methods are with (n, n+1) and (n, n)-threshold. The former method [7] employs the (n, n)-threshold scenario. This scheme offers a promising result if n is even. However, this scheme less resists from the incorrectness problem on facing n as odd number. The proposed method simply overcomes this problem by using three different approaches. In addition, it enjoys the advantage of simple image encryption [12] for improving security. The proposed method can be effectively implemented in the cloud computing environments under using the frameworks such as in [14-16]. The proposed method can also be deployed into another applications. The rest of this paper is organized as follows. Related work on former MSS scheme with its problem on dealing odd number is provided in Section 2. Section 3 proposes some approaches for overcoming the problem of former scheme [7] by incorporating random image, transforming into nk encrypted secret images, and exploiting double masking coefficients. Extensive experimental results on the proposed image encryption and MSS system are detailed reported and discussed in Section 4. The conclusions and future works are finally delivered at the last part. 2 Related Work This section reviews the former existing scheme on MSS (n, n) and its slight limitation for color image. The MSS scheme aims to pull n shared images out from n secret images before sending it to the decoder via communication channel. Figure 1 illustrates the general framework of MSS (n, n) scheme. Herein, the sender side produces n shared images. Whereas, the receiver module performs reconstruction process to