Abstract: An access control system and a method performed therein, for handling access to an access-restricted physical resource. The method comprises, by means of a first credential reader, receiving an initiating access request credential initiating a request to give one or more visitors access to a first access-restricted physical resource. The method further comprises, by means of the first credential reader, receiving a visitor credential for each visitor for which access is requested, and, by means of a second credential reader, receiving a finalising access request credential finalising the request to give the one or more visitors access. Furthermore, the method comprises, by means of a first resource controller, allowing a visitor to access the first access-restricted physical resource upon presenting the visitor's visitor credential to the first credential reader.

Abstract: An access control system and a method performed therein, for handling access to an access-restricted physical resource. The method comprises, by means of a first credential reader, receiving an initiating access request credential initiating a request to give one or more visitors access to a first access-restricted physical resource. The method further comprises, by means of the first credential reader, receiving a visitor credential for each visitor for which access is requested, and, by means of a second credential reader, receiving a finalising access request credential finalising the request to give the one or more visitors access. Furthermore, the method comprises, by means of a first resource controller, allowing a visitor to access the first access-restricted physical resource upon presenting the visitor's visitor credential to the first credential reader.

Abstract: A device may correspond to a physical access controller in a distributed physical access control system. A method, performed by the device in a distributed system, may include detecting that another device in the distributed system has become unavailable; determining that a loss of consensus has occurred in the distributed system based on detecting that the other device has become unavailable; generating a list of available devices in the distributed system; and sending an alarm message to an administrative device, wherein the alarm message indicates the loss of consensus and wherein the alarm message includes the list of available devices.

Abstract: A device may correspond to a physical access controller in a distributed physical access control system. A method, performed by the device in a distributed system, may include detecting that another device in the distributed system has become unavailable; determining that a loss of consensus has occurred in the distributed system based on detecting that the other device has become unavailable; generating a list of available devices in the distributed system; and sending an alarm message to an administrative device, wherein the alarm message indicates the loss of consensus and wherein the alarm message includes the list of available devices.