To a method for accessing a service, at least one first user device executes a first application that communicates with a second user device application. The first user device sends to a remote server data relating to the first application execution, as a first user device report. The data relating to the first application execution includes information relating to either an incoming event or an outgoing event and at least one attribute relating to the first application execution. The remote server determines, based upon at least the first user device report, a trust level relating to the first user device. A third user device sends to the remote server a request for getting a trust level relating to the first user device. The remote server sends to the third user device, as a request response, the trust level relating to the first user device.