Design and Implementation of AES and SHA-256 Cryptography for Securing Multimedia File over Android Chat Application

In the current era of globalization, security is one of the most important aspects in the development of communication applications, especially when sending confidential files. Advanced Encryption Standard (AES) is one method that can be used to secure data by encrypting and decrypting an information. AES is also an algorithm that has a fast encryption process and has been widely implemented in various fields. To provide data security that is transferred to the network, AES is considered a fast and best algorithm. AES is an open source cryptography with symmetric keys used for encryption and decryption of files. Files to be encrypted are multimedia files such as images, audio and video. The file is entered into the application, then the user inputs a key that is encrypted with the SHA-256 algorithm to secure the contents of the file. Encrypted files are stored in the UUencoding format to avoid the compression process when sending files via the chat application. The file is also safer, because the message cannot be seen directly. Based on the results of experiments in this study, multimedia file encryption applications have been successfully built. Although the process of encryption and decryption changes the size of the original file a little, the contents and meaning of the file remain the same and has been wrapped up by measuring the PNSR value that produces an infinity value.