International Journal of Computer Applications (0975 – 8887) Volume 119 – No.7, June 2015 5 A Spatial Domain Watermarking Approach for Digital Images based on Image Features built on Formal Concepts Analysis Quist-Aphetsi Kester 123 , Laurent Nana 2 , Anca Christine Pascu 2 , Sophie Gire 2 , Jojo M. Eghan 3 , and Nii Narku Quaynor 3 1 Lab-STICC (UMR CNRS 6285), European University of Brittany, University of Brest, France 2 Faculty of Informatics, Ghana Technology University College, Accra, Ghana 3 Department of Computer Science and Information Technology, University of Cape Coast ABSTRACT A proof of ownership based on digital forensics evidence is the way forward in solving ownership disputes in the ever growing cyberspace that confronts us today. A strong proof beyond all reasonable doubts with the good standing of the law provides victory for a case before a competent court of law. The Society we live in is governed by laws and laws need evidence to pass judgments and not any kind of evidence but evidence compelling enough to attract the passing of judgment. Lessons learnt from the past of the failures of the court to provide and use strong verified evidence due to limitations of scientific evidence such as DNA, surveillance videos, authenticable images etc. have cost human life’s freedom and having access to a fair trial. We cannot wait till certain loopholes are exploited in our digital cyber evolution before we get it fixed. Hence stronger and a more compelling techniques are needed for image authentication and identification. In our work, we proposed a spatial domain watermarking approach for digital images based on image features built on formal concepts analysis. We adopt the use of formal concept analysis due to the fact that a change in a pixel value can result in a change in the lattice generated from the image. We presented our results and they showed to be very effective. General Terms Security, watermarking, image processing Keywords Formal Concept Analysis, Digital image, encryption, authentication, watermarking 1. INTRODUCTION A world with high dependency on digital information processing cannot do without digital evidence in solving cases. The cyber world has interconnected with the physical world over the decades in such a way that the cyber –physical relationships will be hard to do away with. Collection of multimedia data through surveillance devices are of key interest to the law enforcement agencies as well private property and home owners. Evidence collected by these devices in one way or the other are used to support actions being taken by then in a form of defense or a support to prosecute an individual. Hence these collected data needs various levels of authentication and security. Police are are now encouraged to wear body cameras inline of their duty besides their dash camera on their patrol vehicles in other to collect a vital and supporting evidence for to justify a course of an action. State buildings and public places now have cameras including those that have biometric data collection capabilities in screening and observing events at public places. These devices record crime and they are presented to the law courts as compelling evidences in support of a case before them. Private businesses and home owners adopt such way of collecting evidence to using an eye witness. The digital images present stronger evidence to an eye witness’s narration and the evidences derived from these digital devices can be compelling enough for the prosecution of a person. So reliable as a court of competent jurisdiction may be on these evidences as a compelling proof of passing effective prosecution may be dangerous to the fair trial of a person under prosecution if the footage obtained or the images do not have a forensically authentic support. Yet still as cyber security experts, we are fully aware that the strength of our dependence on digital evidence depends on the time of the technology deployed as well as the availability of the knowledge of potential alterations capable by an adversary in messing up with the evidence or altering it. No matter how strong a forensic process may be in a case today, its relevance in tomorrow’s case by referencing may be useless. This is because case laws are the bedrock of most law courts rulings and referral to the engagement of techniques as well. Therefore the need for a one step ahead forensics technique is of a key importance when considering forensics approaches. Henceforth evolving techniques of digital evidence have to be deployed in the verification and authentication of collected or stored digital multimedia data. Forensic data may be stored in the cloud. These cloud storage locations can be private or public. Cloud security is mainly limited to access security and only few provide data security with user level authentication. This is because firms also have to mine cloud data for other unauthorized purposes like for marketing etc. But Forensic data are now finding their ways into the cloud in order to support distributed nature of policing activities as well as easy access to interconnected crime labs or databases. Authentication in change or validity of these digital images is very crucial for criminal proceedings hence we proposed an approach in contribution to the solutions that exists in these domains. Our approach has to work in spatial domain on the pixel values due to the dependency of the composed image on the data. A change in the image can easily be detected by our proposed approach. The following sections explains our adopted approach. The paper has the following structure: section 2 related works, section 3 Methodology, section 5 results and analysis, and section 6 concluded the paper.