Dynamic domain key exchange for authenticated device to device communications
A method of dynamically generating a domain based public group key and private member keys using a domain key agent, a domain key service of a domain key broker, and a domain key distribution center. The method includes: sending to the domain key service of a domain key broker a request for a private member key for the domain, wherein the request includes proof of possession of a vehicle private key associated with a vehicle certificate and a vehicle public key; receiving from the domain key service a private member key and a public group key; sending a message digitally signed using the member private key; verifying the digital signature on the received message using the public group key; and dynamically renewing the public group key and private member key based on the domain.
1. A method for secure message exchanges by a vehicle traversing multiple autonomous domains using i) a domain key agent, a wireless supplicant, and a domain keystore at a vehicle, ii) a domain key service and a wireless authenticator at a domain key broker, iii) a domain key factory service at a remote domain key distribution center, and iv) an enrollment service at a remote enrollment server, the method comprising:
prior to communicating with any vehicle in a domain, scanning, by the wireless supplicant on the vehicle, a wireless network for a domain of the autonomous domains by a service set identifier (SSID) and channel for the domain;
retrieving, by the domain key agent on the vehicle, a group public key, a member private key and a member certificate from the domain keystore on the vehicle for the domain SSID;
inspecting, by the domain key agent on the vehicle, the retrieved member certificate for validity of the member certificate;
in response to a determination that the member certificate is invalid, performing, by the domain key agent on the vehicle, an authentication ceremony with the wireless authenticator of the domain key broker by:
receiving, by the domain key agent on the vehicle and from the domain key broker, a challenge encrypted using a vehicle public key; and
transmitting, by the domain key agent on the vehicle and to the domain key broker, a decrypted version of the challenge for authentication;
querying, by the domain key agent on the vehicle from the wireless authenticator on the domain key broker, for a domain key service address and service port of the domain;
in response to a successful authentication in the authentication ceremony, requesting, by the domain key agent on the vehicle, from the domain key service, and using the domain key service address and the service port, the group public key, the member private key and the member certificate for the domain SSID;
storing, by the domain key agent on the vehicle, the received group public key, the member private key and the member certificate for the domain SSID in the domain keystore on the vehicle, wherein the group public key is specific to the domain and different from the vehicle public key used in the authentication ceremony, wherein the group public key is associated with each of a plurality of member private keys for the domain;
signing, by the domain key agent on the vehicle, messages to other vehicles in the domain using the retrieved member private key for the vehicle in the domain; and
verifying, by the domain key agent on the vehicle, messages from other vehicles in the domain using the retrieved group public key for the domain.
2. The method of claim 1 , wherein the authentication ceremony uses at least one of a nonce, a vehicle unique identifier, and a vehicle certificate.
3. The method of claim 1 , wherein the challenge encrypted using the vehicle public key in the received vehicle certificate by the wireless authenticator on the domain key broker must be decrypted using the vehicle private key on the vehicle to generate a response to the wireless authenticator.
4. The method of claim 1 , wherein the domain keystore of the domain key agent comprises at least one of a table of cached records associated to a SSID, a domain type, a group public key, a member private key, a member certificate, and a timestamp.
5. The method of claim 1 , wherein the scanning discovers the wireless network to communicate with the domain key broker specific to the domain.