In the recent era, biometrics is one of the most used authentication systems. Generally, biometric systems are based on imaging technology, which works on scanned images. This system processes the image and compares it with the database and decides authenticity of user. Authentication and faster response are the key objectives of all biometric systems, but they suffered from a serious issue i.e., security breach. In this article, a Cellular Automata based method is introduced, which processes the image and identify possible security breaches. The proposed method analysis all the pixels of the image and maps a rule, which processes the image and generates a gray image by defining all the possible edges of the image objects. The gray image contains only binary values, which may reduce the chance of breach and decrease the comparison time of gray image with database. In this paper, the proposed method is experimented on the open-source dataset and the results are validated using authentication parameters.