The IM system with a cryptographic feature

The paper does concern the IM (Instant Messaging) system with a cryptographic feature designed for the portable subscriber appliances working with the Android operating system. Unlike the existing applications with a text messaging function, the proposed system uses XML (Extensible Markup Language) tool to specify the message structure and in order to ensure appropriate confidentiality of talks it does encrypt messages to be transmitted between the end user and server system. The results of a preliminary performance evaluation of encryption algorithms, used in the proposed system, will be discussed together with possible applications and further modifications of that IM system.