Method of key distribution by trusted nodes for a vehicular ad hoc network, VANET, wherein said vehicular ad hoc network is composed of nodes, a node being either a mobile vehicle node equipped with an on-board unit or a static road-side unit node, herewith referred respectively as vehicle nodes (A, B, C, D, E, F, G) and RSU nodes (R1, R2, R3), wherein said RSU nodes have a permanent connection to a certificate authority, CA, said CA being responsible for a specific geographic region in which the VANET is comprised and said CA acting as the root of trust for the VANET, and wherein the VANET nodes have at least one pair of public-private keys and the corresponding certificates, issued by said CA, wherein said method comprises the steps of: - each vehicle node, on entering said specific geographic region, requests a set of keys from an RSU node that is within range and within that region, either by direct communication, or by through multi-hop communication, wherein said vehicle node sends a key request to said RSU node, said request including the vehicle node public key; - said RSU node sends said vehicle node a set of private keys, selected from a pool of private keys available to the RSU node, said set of keys being encrypted with the vehicle node public key, wherein said set of private keys also includes a key identifier for each private key in said set; characterised in that it further comprises the steps of - said RSU node sends said vehicle node a list with the key identifiers of the private keys shared by said vehicle node and the other vehicle nodes that have most recently contacted said RSU node for a predetermined period of time; - said RSU node informs the VANET nodes, within a neighborhood of a predetermined number of hops from said RSU node, of the presence of said vehicle node and of the identifiers of keys obtained by said vehicle node; such that two vehicle nodes are able to immediately establish a secure connection if there are shared keys between those two vehicles, without further interaction, by deriving a new shared secret which is a cryptographic hash function of the keys shared by said two nodes. - each vehicle node, on entering said specific geographic region, requests a set of keys from an RSU node that is within range and within that region, either by direct communication, or by through multi-hop communication, wherein said vehicle node sends a key request to said RSU node, said request including the vehicle node public key; - said RSU node sends said vehicle node a set of private keys, selected from a pool of private keys available to the RSU node, said set of keys being encrypted with the vehicle node public key, wherein said set of private keys also includes a key identifier for each private key in said set; characterised in that it further comprises the steps of - said RSU node sends said vehicle node a list with the key identifiers of the private keys shared by said vehicle node and the other vehicle nodes that have most recently contacted said RSU node for a predetermined period of time; - said RSU node informs the VANET nodes, within a neighborhood of a predetermined number of hops from said RSU node, of the presence of said vehicle node and of the identifiers of keys obtained by said vehicle node;