Application of the DCT Algorithm to Protect Image Files with Key Symbols

Abstract

Image file protection is an important aspect in managing and transmitting visual data in today's digital era. One effective method for protecting images is to use the Discrete Cosine Transformation (DCT) algorithm based on the principle of randomization with key symbols. This research aims to describe the application of the DCT algorithm in the context of image protection using key symbols as a security method. This research includes the main stages, namely randomization of the original image using predetermined key symbols, transformation of the image to the DCT domain, and storage of the scrambled image. By scrambling the image using key symbols known only to authorized parties, the original image can be changed significantly so that it is difficult to reconstruct by unauthorized parties. In addition, the results of this DCT transformation can also be encrypted using a strong cryptographic algorithm, thereby increasing the security level of image protection. The research results show that this method is effective in protecting image files from unauthorized access and unwanted surveillance. The final result of implementing the DCT algorithm with this key symbol is an image that is protected with a high level of security and can be restored correctly by authorized parties using the appropriate key symbol. This research has broad potential application in a variety of contexts, including data security, confidential image storage, and secure image transmission over communications networks. Thus, this method can make a positive contribution in overcoming information security challenges in an increasingly complex digital era.