Method for producing, allocating and checking authorisation approvals that are required in order to fulfil tasks specified by an action plan through performance, by a service technician, of actions on a device or component of a distributed structure, characterised by the method steps of: - generating at least one authorisation approval that is bound to an identity certificate of the service technician which is stored on a storage medium carried or able to be carried by the service technician and has a limited period of validity by a planning support program that produces the action plan, which authorisation approval is required for fulfilling particular tasks specified by the action plan and is generated with only a short validity, whereby it is ensured that authorisations can be revoked within a very short time, without revoking the identity certificate to which the authorisation approvals are linked; - signing the authorisation approval with a non-public key; - storing the signed authorisation approval on a storage medium carried or able to be carried by the service technician; - making at least the identity certificate and the signed authorisation approval available to the device or component by the service technician; - checking the period of validity of the identity certificate by the device or component; - checking the signature of the signed authorisation approval by the device or component with the aid of a public key associated with the non-public key used for generating the signature as well as a main certificate of a certification authority that issued the public key; - wherein both the public key and the main certificate of the certification authority are available or are made available to the device or component; - checking the authorisation approval by the device or component; and - if the result of all the checks confirms the identity of the service technician and allows the tasks to be fulfilled, granting of the permission to the service technician by the device or component to carry out the actions requiring to be performed in order to fulfil the tasks set or specified by the action plan. - generating at least one authorisation approval that is bound to an identity certificate of the service technician which is stored on a storage medium carried or able to be carried by the service technician and has a limited period of validity by a planning support program that produces the action plan, which authorisation approval is required for fulfilling particular tasks specified by the action plan and is generated with only a short validity, whereby it is ensured that authorisations can be revoked within a very short time, without revoking the identity certificate to which the authorisation approvals are linked; - signing the authorisation approval with a non-public key; - storing the signed authorisation approval on a storage medium carried or able to be carried by the service technician; - making at least the identity certificate and the signed authorisation approval available to the device or component by the service technician; - checking the period of validity of the identity certificate by the device or component; - checking the signature of the signed authorisation approval by the device or component with the aid of a public key associated with the non-public key used for generating the signature as well as a main certificate of a certification authority that issued the public key; - wherein both the public key and the main certificate of the certification authority are available or are made available to the device or component; - checking the authorisation approval by the device or component; and - if the result of all the checks confirms the identity of the service technician and allows the tasks to be fulfilled, granting of the permission to the service technician by the device or component to carry out the actions requiring to be performed in order to fulfil the tasks set or specified by the action plan.