y controls and service disruption. Malicious users can easily tap (eavesdrop) IP traffic, redirect traffic, insert false packets, modify packets, mount denial of service attacks and introduce harmful software into systems. Future wars might well be fought in cyberspace. One of the greatest threats in all computer systems is the company's own staff. There are not SO many investigations done in this area but most of them show that the staff inside the company is one of the most frequent intruders in computer systems. 6.3.1 SECURITY: A FUNDAMENTAL PLAN? For the actor the security area can be seen as a huge fundamental technical plan with relationships and implications to most other plans. This statement will be developed later (e.g. see Figure 6.11). Whereas security measures protect the service and the functioning of other plans, they have often an adverse effect on QoS. One reason is that many security measures increase the overhead of the traffic, simultaneously hiding header information in encapsulated packets. Sometimes there is a need to 'undress' the packet, especially in gateways, when changing between technical solutions like in a WAP gateway or a proxy server. This is not attractive for the staff responsible for security. This also means indirectly that the service is affected in a negative way. At the very least extra cost has been incurred. Another negative impact is that the availability is reduced by the number of precautions, such as passwords and other types of access restrictions. The overall immediate result becomes a significant cost and possibly a reduced QoS. This cost has to be paid by the users in one way or another. But this is not the end of the story: as mentioned the user has some fundamental requirements on the information transfer: integrity and confidentiality. Once these requirements are jeopardized, it has a severe impact on the utilization of the networks. The first type of service to be affected is transactional services, typically B2B and B2C. Consequently e-commerce services are r