A method at a primary communication device for participating in log-in of a secondary communication device where, upon recognizing a successful log-in of the primary communication device, a request for extended log-in to the secondary communication device is received from the secondary communication device. Instruction to initiate the requested extended log-in is transmitted to the secondary communication device. After having received physiological data, associated with the user of the secondary communication device, the first physiological data is compared with the physiological data provided from the secondary device for determining whether there is a match between the compared physiological data. In case of a match at least one credential is transmitted to the secondary communication device, whereas no credential is transmitted to the secondary device if no match is determined.