UNIFORM COMMUNICATION PROTOCOLS FOR COMMUNICATION BETWEEN CONTROLLERS AND ACCESSORIES

• US 20150222517A1
• Filed: 02/05/2015
• Published: 08/06/2015
• Est. Priority Date: 02/05/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: McLaughlin, Kevin P., Bradley, Bob, Golembeski, Gregg Jr., Burks, Andrew, Rama, Srinivas, Nadathur, Anush, Abuan, Joe, Dooley, Craig, Mathias, Arun
• Granted Patent: US 9,979,625 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/3051 Monitoring arrangements for monitoring the configuration of the computing system or of the computing system component, e.g. monitoring the presence of processing resources, peripherals, I/O links, software programs verification or detection of system hardware configuration G06F11/2247
• CPC Class Codes: G06F 21/445 by mutual authentication, e.g. between devices or programs
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/126 the source of the received data
• CPC Class Codes: H04L 63/18 using different networks or channels, e.g. using out of band channels cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/0827; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L9/3215
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/04 specially adapted for terminals or networks with limited capabilities; specially adapted for terminal portability
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/303 Terminal profiles
• CPC Class Codes: H04L 67/55 Push-based network services
• CPC Class Codes: H04L 9/006 involving public key infrastructure [PKI] trust models network architecture or network communication protocol for supporting authentication of entities using certificates in a packet data network H04L63/0823
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3263 involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 12/06 : Authentication
• CPC Class Codes: H04W 12/50 : Secure pairing of devices
• CPC Class Codes: H04W 4/70 : Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 4/80 : Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication

Abstract

A uniform protocol can facilitate secure, authenticated communication between a controller device and an accessory device that is controlled by the controller. An accessory and a controller can establish a pairing, the existence of which can be verified at a later time and used to create a secure communication session. The accessory can provide an accessory definition record that defines the accessory as a collection of services, each service having one or more characteristics. Within a secure communication session, the controller can interrogate the characteristics to determine accessory state and/or modify the characteristics to instruct the accessory to change its state.

Claims

1. A method comprising:

detecting, by a controller, an accessory that is available for pairing;

performing, by the controller, a pair setup operation to establish a pairing with the accessory, the pair setup operation including;

establishing a shared secret using an out-of-band information item exchanged between the accessory and the controller;

using the shared secret to securely exchange a long-term public key of the accessory and a long-term public key of the controller; and

securely and persistently storing, by the controller, the long-term public key of the accessory in association with an identifier of the accessory;

obtaining, by the controller, an accessory definition record from the paired accessory, the accessory definition record including a set of services, each service having a set of characteristics, each characteristic representing an aspect of accessory state; and

communicating, by the controller, a request to the paired accessory to modify one or more of the characteristics specified in the accessory definition record, the request being interpretable by the paired accessory as an instruction invoke an operation of the paired accessory.

2. The method of claim 1 further comprising, prior to invoking the operation of the accessory:

performing, by the controller, a pair verify operation with the paired accessory, the pair verify operation including;

sending, to the paired accessory, a proof that the controller has the long-term public key of the paired accessory and a long-term secret key corresponding to the long-term public key of the controller; and

receiving, from the paired accessory, a proof that the paired accessory has the long-term public key of the controller and a long-term secret key corresponding to the long-term public key of the paired accessory,

wherein the controller invokes the operation of the paired accessory only if the pair verify operation succeeds.

3. The method of claim 2 wherein performing the pair verify operation further includes generating a session key and wherein the session key is used to encrypt the request to modify one or more of the characteristic specified in the accessory definition record.

4. The method of claim 1 further comprising:

sending, by the controller, a request to the paired accessory to subscribe to notifications of a change in a particular characteristic from the set of characteristics defined in the accessory definition record, wherein the request to subscribe specifies the particular characteristic and further specifies a notification mode.

5. The method of claim 4 wherein the specified notification mode is an event-message notification mode, the method further comprising:

subsequently to sending the request to subscribe, receiving, by the controller an unsolicited response message from the accessory, the unsolicited response message including a notification of a change in the characteristic specified by the controller.

6. The method of claim 1 wherein the out-of-band information item includes one or more of:

a setup code provided to a user by the accessory and provided to the controller by the user;

or

digital certificate verification information obtained by the controller from a source other than the accessory, the digital certificate verification information usable to verify a digital certificate and signature received by the controller from the accessory.

7. The method of claim 1 further comprising:

performing, by the controller, a pair add operation with the paired accessory on behalf of another controller, wherein the pair add operation includes providing to the accessory, by the controller, one or both of a long-term public key of the other controller or a certificate usable by the accessory to verify the other controller.

8. A controller comprising:

a communication interface to communicate with one or more accessories;

a secure storage element to securely store pairing records for one or more paired accessories;

a data storage element configured to store accessory definition records for one or more paired accessories; and

a processing subsystem coupled to the communication interface, the secure storage element, and the data storage element, the processing subsystem configured to;

establish a pairing with one or more accessories, wherein establishing a pairing with an accessory includes;

obtaining an out-of-band information item;

securely obtaining, from the accessory, a long-term public key of the accessory and a proof that the accessory has the out-of-band information item;

securely providing a long-term public key of the controller to the accessory; and

creating and persistently storing a pairing record for the accessory in the secure storage element, the pairing record including a long-term public key of the accessory;

obtain, after establishing a pairing with an accessory, an accessory definition record from the paired accessory, the accessory definition record including a set of services, each service having a set of characteristics, each characteristic representing an aspect of accessory state; and

invoke an operation of the paired accessory by communicating to the accessory a request to modify one or more of the characteristics specified in the accessory definition record.

9. The controller of claim 8 wherein the communication interface includes at least two different transport protocol stacks and wherein the communication interface selects one of the transport protocol stacks to be used for communicating with a particular accessory.

10. The controller of claim 9 wherein the at least two different transport protocol stacks include a Bluetooth LE protocol stack and an HTTP/IP protocol stack.

11. The controller of claim 8 wherein the processing subsystem is further configured to establish a pair-verified session with a paired accessory, wherein establishing the pair verified session includes:

sending, to the paired accessory, a proof that the controller has the long-term public key of the paired accessory and a long-term secret key corresponding to the long-term public key of the controller;

receiving, from the paired accessory, a proof that the paired accessory has the long-term public key of the controller and a long-term secret key corresponding to the securely stored long-term public key of the paired accessory; and

establishing one or more session keys usable to encrypt subsequent messages exchanged between the controller and the paired accessory.

12. The controller of claim 11 wherein the processing subsystem is further configured to perform a pair add operation within an established pair-verified session, wherein performing the pair add operation includes sending to the paired accessory a long-term public key of another controller with which the paired accessory is to establish a pairing.

13. A method comprising:

advertising, by an accessory, that the accessory is available for pairing;

performing, by the accessory, a pair setup operation to establish a pairing with a controller, the pair setup operation including;

establishing a shared secret using an out-of-band information item exchanged between the accessory and the controller;

using the shared secret to securely exchange a long-term public key of the accessory and a long-term public key of the controller; and

securely and persistently storing, by the accessory, the long-term public key of the controller in association with an identifier of the controller,

providing, by the accessory to the paired controller, an accessory definition record for the paired accessory, the accessory definition record including a set of services, each service having a set of characteristics, each characteristic corresponding to an aspect of accessory state;

receiving, by the accessory, a request from the paired controller to modify one or more of the characteristics specified in the accessory definition record; and

performing, by the accessory, an invoked operation in response to the received request.

14. The method of claim 13 further comprising:

detecting, at the accessory, a user action indicating that the accessory should enter a pairing mode,

wherein advertising that the accessory is available for pairing is performed in response to detecting the user action.

15. The method of claim 13 wherein, after performing the pair setup operation with one controller, the accessory subsequently refuses to perform the pair setup operation with any other controller for as long as the long-term public key of the paired controller remains securely and persistently stored.

16. The method of claim 13 further comprising, prior to receiving the request from the controller to modify one or more of the characteristics:

performing, by the accessory, a pair verify operation with the paired controller, the pair verify operation including;

receiving, from the paired controller, a proof that the paired controller has the long-term public key of the accessory and a long-term secret key corresponding to the long-term public key of the paired controller; and

sending, to the paired controller, a proof that the accessory has the long-term public key of the paired controller and a long-term secret key corresponding to the long-term public key of the accessory,

wherein the accessory performs the invoked operation in response to the request only if the pair verify operation succeeds.

17. The method of claim 16 wherein performing the pair verify operation further includes generating a session key and wherein the session key is used to decrypt the received request to modify one or more of the characteristic specified in the accessory definition record,

wherein the accessory performs the invoked operation only if the received request is successfully decrypted.

18. The method of claim 13 further comprising:

receiving, by the accessory, a request from a paired controller to subscribe to notifications of a change in a particular characteristic from the set of characteristics defined in the accessory definition record, wherein the request to subscribe specifies the particular characteristic and further specifies a notification mode; and

in the event that the specified characteristic changes, generating, by the accessory, an update notification for the paired controller based on the specified notification mode.

19. The method of claim 18 wherein the specified notification mode is an event-message notification mode and wherein generating the update includes sending to the paired controller an unsolicited response message, the unsolicited response message including a notification of the change in the specified characteristic.

20. The method of claim 13 wherein the out-of-band information item includes a setup code stored locally by the accessory and communicated to the controller using an out-of-band communication channel.

21. The method of claim 13 further comprising:

performing, by the accessory, a pair add operation with the paired controller on behalf of another controller, wherein the pair add operation includes;

receiving from the paired controller, by the accessory, a long-term public key of the other controller; and

securely and persistently storing, by the accessory, the long-term public key of the other controller in association with an identifier of the other controller,

wherein, subsequently to the pair add operation, the other controller is treated by the accessory as a second paired controller.

22. An accessory comprising:

a communication interface to communicate with one or more controllers;

an operational component;

a secure storage element to securely store pairing records;

an accessory data storage element configured to store an accessory definition record, the accessory definition record including a set of services, each service having a set of characteristics, each characteristic representing an aspect of accessory state including a state of the operational component; and

a processing subsystem coupled to the communication interface, the operational component, the secure storage element, and the accessory data storage element, the processing subsystem configured to;

establish a pairing with one or more controllers, wherein establishing a pairing with a controller includes;

obtaining an out-of-band information item;

securely obtaining, from the controller, a long-term public key of the controller and a proof that the controller has the out-of-band information item;

securely providing a long-term public key of the accessory to the controller, and

creating and persistently storing a pairing record for the controller in the secure storage element, the pairing record including a long-term public key of the controller;

provide, after establishing a pairing with a controller, the stored accessory definition record to the paired controller, and

receive, from the paired controller, a request to modify one or more of the characteristics specified in the accessory definition record; and

effect an operation of the at least one operating component in response to the request.

23. The accessory of claim 22 wherein the processing subsystem is further configured to establish a pair-verified session with a paired controller, wherein establishing the pair-verified session includes:

receiving, from the paired controller, a proof that the paired controller has the long-term public key of the accessory and a long-term secret key corresponding to the securely stored long-term public key of the paired controller;

sending, to the paired controller, a proof that the accessory has the long-term public key of the paired controller and a long-term secret key corresponding to the long-term public key of the accessory; and

establishing one or more session keys usable to encrypt subsequent messages exchanged between the paired controller and the accessory.

24. The accessory of claim 23 wherein the processing subsystem is further configured to perform a pair add operation within an established pair-verified session, wherein performing the pair add operation includes:

receiving, from the paired controller, a long-term public key of another controller with which the accessory is to establish a pairing; and

creating and persistently storing a pairing record for the other controller in the secure storage element, the pairing record including the received long-term public key of the other controller.

25. The accessory of claim 22 wherein the at least one operational component includes one or more of:

a lock mechanism;

a light bulb;

a door opener;

or

a camera.