With the development of modern computer networks, a new advanced channel for communication emerges. The future Swedish defence will use multiple systems connected with high-speed networks for information sharing. Within this environment, the issue of administration of authorisation is crucial. SaabTech Systems and SICS have in collaboration developed a model and a prototype for decentralised administration of authorisations. The model is based on delegation of authorisations extended with a component to define constraints on delegations. This enables efficient decentralised administration that reflects the management structure of an organization in a natural way, at the same time as it maintains centralised control on the distribution of authorisations. All authorisations must fulfil constraints defined by their sources of authority. The source of authority may, for instance, define in advance how a certain authorisation can be distributed and used, in terms of whom and when it can be delegated. The model supports several schemes for revocation of authorization.