A method for providing access to a physical space , secured by a lock , for provision of a service, the lock being associated with a service consumer , the method being performed in an access coordinator and comprising the steps of: receiving an approval signal from a service consumer device of the service consumer , the approval signal indicating that the service consumer allows a service provider agent of a service provider to open the lock , wherein the approval signal comprises a first access delegation, from the service consumer to the service provider; receiving , from a service provider device of the service provider, a request to assign a service provider agent of the service provider to open the lock ; communicating with the service provider device to use a private key of a cryptographic key pair accessible to the service provider device , the private key being a private key of the service provider, the private key being used to generate service agent access data that is specific for the service provider agent , to allow the service provider agent to open the lock , wherein the service agent access data comprises a second access delegation, from the service provider to the service provider agent, wherein the second access delegation includes the first access delegation, wherein the step of communicating with the service provider comprises commanding the service provider device to provide a first electronic signature of a set of data by using the private key, wherein the service agent access data comprises the set of data and the first electronic signature; and transmitting the service agent access data to a service provider agent device associated with the service provider agent . receiving an approval signal from a service consumer device of the service consumer , the approval signal indicating that the service consumer allows a service provider agent of a service provider to open the lock , wherein the approval signal comprises a first access delegation, from the service consumer to the service provider; receiving , from a service provider device of the service provider, a request to assign a service provider agent of the service provider to open the lock ; communicating with the service provider device to use a private key of a cryptographic key pair accessible to the service provider device , the private key being a private key of the service provider, the private key being used to generate service agent access data that is specific for the service provider agent , to allow the service provider agent to open the lock , wherein the service agent access data comprises a second access delegation, from the service provider to the service provider agent, wherein the second access delegation includes the first access delegation, wherein the step of communicating with the service provider comprises commanding the service provider device to provide a first electronic signature of a set of data by using the private key, wherein the service agent access data comprises the set of data and the first electronic signature; and transmitting the service agent access data to a service provider agent device associated with the service provider agent . <EOS>