Security is essential in a wireless system. As wireless communications cannot be physically secured, the needs of wireless access present a new series of challenges. Wireless access to enterprise systems puts not only the client device, but also the data, well beyond the physical control of the organization. Sniffing of data traffic can be done without any risk of detection, over a much wider range of locations. Furthermore, the client device, in the case of a cell phone or PDA, is even easier to steal than a laptop computer, with the additional loss of security. Compromise of the wireless client thus poses a double threat to data: the remote access to data the device enables, and immediate access to the downloaded data stored within it. The wireless middleware can thus incorporate a key encryption security mechanism as described elsewhere.
The low bandwidth in a wireless link requires that the volume of data being transmitted be kept as small as possible. For this reason, data should be compressed from the client to the server and from the server to the client. This desire for efficiency contrasts with the processing requirement on the client side. If the client is a laptop computer, then it can have adequate processing power to decompress the data; however, if the client device is a PDA, the amount of processing power available currently is inadequate to decompress large amounts of data in real time.
As optimal-compression algorithms are data specific, the compression algorithm to be used will vary on the type of data. For example, text compression, picture compression, Java class compression, and XML compression, all use specific, different algorithms. The best the middleware can do is to have a library of common compression algorithms it can use to compress uncompressed data depending on the type. Alternatively, the problem of compression can be regarded as an application design consideration and be left to the application developer to elect whether to compress the data or not. The middleware will then only pass data it is given and not attempt to perform any compression.