Abstract—The objective of this study is to enhance the confidentiality and security of the image steganography application by combining cryptography algorithm. In this proposed model, the RSA algorithm is used to encrypt a secret message into an unreadable ciphertext before hiding it in the image. Diffie-Hellman algorithm is used to determine the pixel on an image that will be used to store the message. A system based on the proposed algorithm will be implemented using Java and it will be more secured due to double-layer of security mechanisms which are RSA and Diffie-Hellman. Index Terms—Steganography, Image Steganography, Cryptography, Encryption Algorithm I. INTRODUCTION Nowadays, the rapid evolving of digital communications causes the rate of information dissemination increases. Besides, the confidential information has also been transferred using open channel of communication which increases the criminality problem such as interceptor problems [1]. So, a secured and reliable digital communication is compulsory. Due to this requirement, a safer way to communicate such as cryptography and steganography has been developed. Cryptography is a method to encrypt a secret message into an unreadable form while steganography hides the existence of a secret message [2]. Cryptography and steganography are closely related method where the goal of these techniques is to provide data security and secure communication. Cryptography provides features such as confidentiality, authenticity, non-repudiation, and integrity of data. For example, confidentiality is achieved via an encryption algorithm which scrambles or mixes the private information so that it becomes unreadable to any party except for the intended recipient. In particular, in a cryptographic application, an eavesdropper or unauthorized party is aware of the existence of the private information, and his or her challenge is to decipher the encrypted information. According to [3], cryptography algorithm such as Advanced Data Encryption (AES), Data Encryption Standard (DES), or RSA can be used to transform the information into an unreadable Manuscript received March 20, 2016. This research is fully sponsored by Centre of Research Innovation & Management (CRIM), Universiti Sultan Zainal Abidin (UniSZA), Malaysia. Project No is UniSZA/14/GU (021). Siti Dhalila Mohd Satar, Nazirah Abd Hamid, Fatimah Ghazali, Roslinda Muda, Mustafa Mamat is with Faculty Informatics and Computing, Universiti Sultan Zainal Abidin, Tembila Campus, 22200 Besut, Terengganu, Malaysia Pang Kok An is with Faculty Informatics and Computing, Universiti Sultan Zainal Abidin, Tembila Campus, 22200 Besut, Terengganu, Malaysia form called ciphertext. On the other hand, steganography provides data security by hiding the information in a cover medium so that even the existence of a hidden message is not known to an intruder. Authors [4]-[5] describe steganography can be implemented into a variety of media for example image, audio, and video, however, images could be a powerful host to hide information because the spacious spaces it offers. Moreover, the changes in digital images are usually unnoticeable to a naked eye. Therefore, combining the cryptography with steganography can be the best solution in securing a message. In this paper, the researchers propose a double layer security mechanism on image steganography by encrypting the secret message using RSA algorithm and exploiting the Diffie-Hellman algorithm to determine the pixel in order to embed the secret message in an image. The rest of this paper is organized as follows: Section 2 reviews the related works on the existing methods. Section 3 presents the proposed algorithm to produce a secure steganography. Section 4 discusses the experimental results and section 5 provides the concluding remarks. II. RELATED WORKS According to [6]-[7] there are many image steganographic techniques have been developed. Among these techniques, least significant bit (LSB) technique has been widely used due to its simplicity and speed. LSB is refers to the right most bit in a binary integer. In this technique, LSB replaces the lowest bits in images with secret message bits. LSB in an image is said to have a high capacity of embedding secret message because many pixel value of images can be manipulated and replaced with the secret message. In [8], the researchers combine cryptography and steganography in their works where conventional LSB modification has been improved by randomizing bit number of host message used for embedding secret message. Besides, the sample number containing next secret message bit has been randomized as a second of proposed improvement. In their works, to secure secret message, in case the steganography technique breaks, they used Advanced Encryption Standard (AES) with 256 bits key lengths. The proposed technique has been tested on a .wav file at a sampling frequency of 8000 samples/second with each sample containing 8 bits. The improvised proposed technique works against steganalysis and decreases the probability of secret message being extracted by an intruder. The result of this satisfies the threshold condition and is more difficult for an intruder to break. Another similar approach but using different cryptography algorithm has been proposed by [9]. They used AES algorithm for encryption process for securing ecommerce and Secure Image Steganography Using Encryption Algorithm Siti Dhalila Mohd Satar, Nazirah Abd Hamid, Fatimah Ghazali, Roslinda Muda, Mustafa Mamat, and Pang Kok An Annual Int'l Conference on Intelligent Computing, Computer Science & Information Systems (ICCSIS-16) April 28-29, 2016 Pattaya (Thailand) http://dx.doi.org/10.15242/IAE.IAE0416016 43