Text and file encryption application for blackberry using cipher feedback 8-bit mode

BlackBerry is not just an ordinary smartphone which rich in its multimedia features. BlackBerry also has very reliable internet services, include BlackBerry Messenger, e-mail, other instant messaging, and other internet service that Blackberry Internet Service (BIS) covers. However, there´s an open question that all services that go through BIS is safe or not; considering the data includes text and files which is sent through BIS have to pass through the main server which is located in Canada. Therefor in this paper we chose to make software that can encrypt and decrypt text and even files, which will be sent through BlackBerry´s internet or just to be stored in the BlackBerry device. In this paper, we use cipher block encryption algorithm with Cipher Feedback (CFB) 8-bit mode. This mode is chosen because it suits with the data inside BlackBerry device which is 8-bit aligned. The encryption algorithm uses cipher block encryption with 64-bit block size. We designed the algorithm based on Feistel network combined with some encryption/decryption algorithm. Then the cipher block encryption algorithm is implemented in software based on Java for BlackBerry. In this software development, we use the IDE Eclipse Ganymede with certain plugins. The expected result is software for BlackBerry capable to encrypt and decrypt some texts, either directly typed or saved as files on the BlackBerry device. This software also handles specific file types, such as picture and audio by preserving their file header, and also handles text encryption by transforming the ciphertext data to hex digits. After conducting some experiments, we conclude that the software has good compatibility with many kinds of BlackBerry devices and has good security level.