Zero-steganography using DCT and Spatial domain Muhammad Bilal * , Sana Imtiaz * , Wadood Abdul † and Sanaa Ghouzali ‡§ * Department of Electrical Engineering COMSATS Institute of Information Technology, Islamabad, Pakistan Email: mbilal ce@live.com † Department of Computer Engineering, College of Computer and Information Sciences King Saud University, Riyadh, Kingdom of Saudi Arabia ‡ Department of Information Technology, College of Computer and Information Sciences King Saud University, Riyadh, Kingdom of Saudi Arabia § LRIT Associate Unit to CNRST (URAC 29), Faculty of Sciences Mohamed V-agdal University, Rabat, Morocco Abstract—As the primary concern in conventional steganog- raphy techniques is to make the algorithm immune to ste- ganalysis, their primary focus is on imperceptibility. This paper discusses Zero-steganography, an imperceptible and un- detectable data hiding technique that does not require any steganalysis. The proposed algorithm hides the data based on a relationship between characteristic matrix of the cover image, chaotic sequence and payload; however, no change is made to the cover image. The proposed algorithm is analyzed for robustness against three attacks – low-pass filtering, noise and JPEG compression. Our results show that the proposed algorithm is robust against these attacks with Bit Error Rate (BER) below 20% even for the highest attack intensities. Keywords-Steganography; Zero-steganography; Steganaly- sis; Imperceptibility; Chaos based steganography; I. I NTRODUCTION With the advancement in the field of computer science and advent of digital computers, secure communications are increasingly making use of cryptography. Cryptography techniques are aimed at encrypting the data in order to ensure its security, thus making it incomprehensible for an adversary. However, encryption is not concerned with hiding the existence of secret data from the adversary. Hence, it leads to suspicion which in turn might make data transmission unsuccessful. On the other hand, information hiding techniques, namely steganography and watermarking [1], are methods that are used to hide the existence of secret data. Information hiding techniques are evaluated on the basis of their impercep- tibility, robustness, capacity and security. Steganography concentrates mainly on imperceptibility, and is used for com- municating secret messages using any regular digital carrier – such as audio, video, text files or images. Watermarking, on the other hand, concentrates relatively less on capacity as it is mainly used for protection of intellectual property rights and copyright purposes. The aim of digital watermarking is to attain robustness against removal, destruction and counterfeiting [2]. Steganography, in general, is the process of hiding in- formation in the cover medium such that it is undetectable, which makes it a prime candidate for secret communication. Image steganography is carried out by manipulating and altering image pixels to hide the secret data [3], [4]. In addition to spatial domain, image steganography is also carried out in several transform domains [5]. A generic description of the steganographic process is as follows: cover data + secret data embedding algorithm -----------→ stego data (1) The different requirements of steganography and water- marking techniques could be better understood by the visual requirement model given in Figure 1 [6]. While watermark- ing algorithms are primarily concerned with the robustness of the embedded watermark, steganography algorithms place prime importance on the imperceptibility and capacity of the algorithm. Figure 1: Requirement model Cao et al. proposed a digital image zero-watermarking method based on discrete wavelet transform (DWT) and chaotic modulation [7]. This concept works out logics in which no change is made to the carrier, hence rendering the algorithm undetectable. In this case, a key is developed by observing some relationships between the payload and cover image. Zero-watermarking is a relatively new field and can be effectively used to solve the problems which were difficult to address using conventional watermarking 978-1-4799-0792-2/13/$31.00 ©2013 IEEE