Key rotation for device application authentication
In various embodiments, a server stores a set of cryptographic keys associated with a client that includes a server-stored bootstrap key, a server-stored authentication key, and a server-stored proposed key. The server receives an authentication request from the client that includes a client-indicated bootstrap key, a client-indicated authentication key, and a client-indicated proposed key. The server makes a determination that the client is authenticated based in part on whether there is a match between the client-indicated authentication key and either the server-stored authentication key or the server-stored proposed key. The server provides, based on the determination, an authentication response to the client indicating that the client has been authenticated.
1. A method comprising:
storing, by a server, a set of cryptographic keys associated with a client that includes a server-stored bootstrap key, a server-stored authentication key, and a server-stored proposed key;
receiving, at the server, an authentication request from the client that includes a client-indicated bootstrap key, a client-indicated authentication key, and a client-indicated proposed key;
making, by the server, a determination that the client is authenticated based in part on whether there is a match between the client-indicated authentication key and either the server-stored authentication key or the server-stored proposed key; and
providing, by the server and based on the determination, an authentication response to the client indicating that the client has been authenticated.
2. The method as in claim 1 , wherein the client sets its client-indicated authentication key to the client-indicated proposed key, in response to the authentication response.
3. The method as in claim 1 , further comprising:
setting, by the server, the server-stored proposed key to the client-indicated proposed key, when the client-indicated authentication key matches the server-stored authentication key.
4. The method as in claim 1 , further comprising:
setting, by the server, the server-stored authentication key to the client-indicated proposed key, when the client-indicated authentication key matches the server-stored proposed key; and
setting, by the server, the server-stored proposed key to be null, when the client-indicated authentication key matches the server-stored proposed key.
5. The method as in claim 1 , further comprising:
entering a recovery mode of the server, in response to a request to do so from a user interface, wherein the server makes the determination that the client is authenticated when the client-indicated bootstrap key matches the server-stored bootstrap key and while in its recovery mode.
6. The method as in claim 5 , further comprising:
setting, by the server and while in its recovery mode, the server-stored authentication key to the client-indicated authentication key and the server-stored proposed key to the client-indicated proposed key.
7. The method as in claim 5 , further comprising:
exiting the recovery mode after making the determination that the client is authenticated.
8. The method as in claim 1 , further comprising:
receiving, at the server and while in a bootstrap initialization mode of the server, an initial authentication request from the client that includes the client-indicated bootstrap key and an initial client-indicated proposed key; and
setting, by the server, the server-stored proposed key to the initial client-indicated proposed key, based on the client-indicated bootstrap key in the initial authentication request matching the server-stored bootstrap key.
9. The method as in claim 8 , further comprising:
exiting the bootstrap initialization mode, when the client-indicated bootstrap key in the initial authentication request matching the server-stored bootstrap key, wherein the server does not compare the server-stored bootstrap key to any client-indicated bootstrap key when the server is not in the bootstrap initialization mode.
10. The method as in claim 1 , wherein the client comprises a sensor or an actuator.
11. An apparatus, comprising:
one or more network interfaces;
a processor coupled to the one or more network interfaces and configured to execute one or more processes; and
a memory configured to store a process that is executable by the processor, the process when executed configured to:
store a set of cryptographic keys associated with a client that includes a server-stored bootstrap key, a server-stored authentication key, and a server-stored proposed key;
receive an authentication request from the client that includes a client-indicated bootstrap key, a client-indicated authentication key, and a client-indicated proposed key;
make a determination that the client is authenticated based in part on whether there is a match between the client-indicated authentication key and either the server-stored authentication key or the server-stored proposed key; and
provide, and based on the determination, an authentication response to the client indicating that the client has been authenticated.
12. The apparatus as in claim 11 , wherein the client sets its client-indicated authentication key to the client-indicated proposed key, in response to the authentication response.
13. The apparatus as in claim 11 , wherein the process when executed is further configured to:
set the server-stored proposed key to the client-indicated proposed key, when the client-indicated authentication key matches the server-stored authentication key.
14. The apparatus as in claim 11 , wherein the process when executed is further configured to:
set the server-stored authentication key to the client-indicated proposed key, when the client-indicated authentication key matches the server-stored proposed key; and
set the server-stored proposed key to be null, when the client-indicated authentication key matches the server-stored proposed key.
15. The apparatus as in claim 11 , wherein the process when executed is further configured to:
enter a recovery mode, in response to a request to do so from a user interface, wherein the apparatus makes the determination that the client is authenticated when the client-indicated bootstrap key matches the server-stored bootstrap key and while in its recovery mode.
16. The apparatus as in claim 15 , wherein the process when executed is further configured to:
set, by the apparatus and while in its recovery mode, the server-stored authentication key to the client-indicated authentication key and the server-stored proposed key to the client-indicated proposed key.
17. The apparatus as in claim 15 , wherein the process when executed is further configured to:
exit the recovery mode after making the determination that the client is authenticated.
18. The apparatus as in claim 11 , wherein the process when executed is further configured to:
receive, while in a bootstrap initialization mode of the apparatus, an initial authentication request from the client that includes the client-indicated bootstrap key and an initial client-indicated proposed key; and
set the server-stored proposed key to the initial client-indicated proposed key, based on the client-indicated bootstrap key in the initial authentication request matching the server-stored bootstrap key.
19. The apparatus as in claim 18 , wherein the process when executed is further configured to:
exit the bootstrap initialization mode, when the client-indicated bootstrap key in the initial authentication request matching the server-stored bootstrap key, wherein the apparatus does not compare the server-stored bootstrap key to any client-indicated bootstrap key when not in the bootstrap initialization mode.
20. A tangible, non-transitory, computer-readable medium storing program instructions that cause a server to execute a process comprising:
storing, by a server, a set of cryptographic keys associated with a client that includes a server-stored bootstrap key, a server-stored authentication key, and a server-stored proposed key;
receiving, at the server, an authentication request from the client that includes a client-indicated bootstrap key, a client-indicated authentication key, and a client-indicated proposed key;
making, by the server, a determination that the client is authenticated based in part on whether there is a match between the client-indicated authentication key and either the server-stored authentication key or the server-stored proposed key; and
providing, by the server and based on the determination, an authentication response to the client indicating that the client has been authenticated.