A passive attack, in which an outsider simply reads messages without revealing his presence, is best countered by encryption. An active attack, in which someone hacks the system disguised as a legitimate user to send, receive, forge or modify messages, requires stronger detection and countermeasures. Higher security solutions may feature strong user authentication, packet encryption and packet integrity protection. Many organizations employ VPNs as integral parts of their security solutions. Until recently VPNs were wired only, but several vendors have developed wireless solutions that allow access behind firewalls from a laptop.
Some new products allow users to make secure connections with handheld devices.
Other solutions deal with the digital key required for decoding encryption. Under WEP standards, many wireless networks use a single secret encryption key that actually is shared among many users. Shared passwords are rarely a good idea. Once one user leaves the company, the key has to be changed. Newer security products offer a more sophisticated approach by assigning each user a unique digital key, which changes during every session.