A method in a network having a plurality of network nodes comprises the following steps performed in a first node of the network: receiving an initiation message from a second node of the network, the received initiation message comprising a public key of the second node; determining at least one of a proximity or velocity measure of the second node; checking whether the at least one determined measure is below a threshold and, when so, emitting a reply message comprising an encrypted part and an encryption key encrypted with the received public key from the second node; and repeatedly emitting status messages, wherein at least a part of each emitted status message is encrypted with the encryption key.