This section covers those concerns that every computer system must address and which nomadicity brings into sharp relief. This discussion ties the motivations and high-level requirements associated with nomadicity to these traditional concerns. It also addresses the relationship between traditional system concerns and nomadicity's concerns for location and context. 4.1 Security Security is broadly divided into authentication and privacy . Authentication means certification that the parties in an exchange are whom they represent themselves to be and that the message received is the same as the message sent.
Privacy means limiting information about an exchange to the intended parties.
Security requirements in computer systems are often met by a mix of administrative controls, cryptography, and physical security measures. In current systems, these mechanisms are usually organized into administrative domains associated with organizations and constrained by geographic areas. Universities on their campuses and businesses at particular sites are examples of security domains. In this situation, the remote access device and communications path almost certainly fall outside the security domain maintained by their organization. Consequently, one impact of device and location independence on security systems is that secure communications paths and devices cannot be assumed.