Design of an Android Application for Secure Chatting

Abstract

—Smart phones have become an essential part in the life of the individuals and their priorities at the present time. The most prominent uses are in chatting and conversation applications. Most of these applications do not provide the required protection and privacy of the data exchanged between users. Yet there are very few mobile chat applications that provides an End-to-End (E2E) security and privacy-preserving service to their clients. In this paper, a secure chatting application with end to end encryption for smart phones that use the android OS has been proposed. The proposed application uses the ECDH algorithm to generate the key pair and exchange to produce the shared key that will be used for the encryption of data by symmetric algorithms. The proposed Application allows the users to communicate via text messages, voice messages, as well as exchange photos. For the text message security the standard AES algorithm with a 128 bit key is used. The generated key (160 bit) minimized to 128 bit length in order to be used by the AES algorithm. For the voice and image security processes the proposed application uses the symmetric algorithm RC4 for this purpose. RC4 provides less security than AES, but it performs faster and this is required for such types and sizes of data.