AUTHENTICATING A MULTIPLE INTERFACE DEVICE ON AN ENUMERATED BUS

• US 20120047368A1
• Filed: 08/20/2010
• Published: 02/23/2012
• Est. Priority Date: 08/20/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chinn, Paul William, Yepez, Roberto G., Dalal, Anand
• Granted Patent: US 8,561,207 B2
• Time in Patent Office: Days
• US Class Current: 713/175
• CPC Class Codes: G06F 21/31 User authentication
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 2221/2129 Authenticate client device independently of the user

Abstract

A method for authenticating a multiple interface accessory device is provided. The method includes receiving enumeration information identifying the multiple interfaces supported by the accessory. The enumeration information includes information about a master interface supported by the accessory. A host device obtains authentication information from the accessory in accordance with a protocol associated with the master interface. Based on the authentication information, the host device determines whether the accessory is authorized to communicate with the host device. In the event that the accessory is authorized, the host device permits communication with the accessory using one or more of the multiple interfaces supported by the accessory.

Claims

1. A method of operating a host device, the method comprising, by the host device:

receiving from an accessory enumeration information identifying a plurality of interfaces as being supported by the accessory;

determining whether the enumeration information identifies the master interface as being supported by the accessory; and

in the event that the enumeration information identifies the master interface as being supported by the accessory;

obtaining authentication information from the accessory in accordance with a protocol associated with the master interface;

determining, based on the authentication information, whether the accessory is authorized to communicate with the host device; and

in the event that the accessory is authorized, permitting communication with the accessory using any of the one or more interfaces identified as being supported by the accessory.

2. The method of claim 1 wherein, in the event that the enumeration information does not identify the master interface as being supported by the accessory, the host device ignores subsequent communication from the accessory.

3. The method of claim 1 wherein the master interface has a plurality of associated attributes, wherein each of the one or more attributes has a predetermined value.

4. The method of claim 3 wherein the one or more attributes include an interface class, an interface sub-class, an interface protocol, and an interface string identifier.

5. The method of claim 3 wherein determining whether the enumeration information identifies the master interface as being supported by the accessory comprises:

verifying that the enumeration information includes the one or more attributes associated with the master interface; and

verifying whether each of the one or more attributes has the predetermined value.

6. The method of claim 1 wherein, receiving the enumeration information comprises receiving the enumeration information via a transport, the transport comprising a Universal Serial Bus (USB) communication protocol.

7. The method of claim 1 wherein, the transport comprises a Bluetooth communication protocol.

8. A computer-readable non-transitory storage medium storing a plurality of instructions that when executed by a processor in a host device, cause the processor to perform a method for authenticating an accessory, the method comprising:

receiving, from the accessory that supports a plurality of interfaces including a master interface, enumeration information identifying one or more of the plurality of interfaces as being supported by the accessory;

determining whether the enumeration information identifies the master interface as being supported by the accessory; and

in the event that the enumeration information identifies the master interface as being supported by the accessory;

obtaining authentication information from the accessory in accordance with a protocol associated with the master interface;

determining, based on the authentication information, whether the accessory is authorized to communicate with the host device; and

in the event that the accessory is authorized, permitting communication with the accessory using any of the one or more interfaces identified as being supported by the accessory.

9. The computer-readable non-transitory storage medium of claim 8 wherein the authentication information includes a digital certificate generated by the accessory.

10. The computer-readable non-transitory storage medium of claim 8 wherein determining whether the accessory is authorized to communicate with the host device comprises:

extracting a digital certificate included in the authentication information;

obtaining a public key associated with the accessory; and

validating the digital certificate using the public key.

11. The computer-readable non-transitory storage medium of claim 8 wherein the master interface has one or more associated attributes and each of the one or more attributes has a predetermined value.

12. The computer-readable non-transitory storage medium of claim 11 wherein determining whether the accessory supports the master interface comprises:

determining whether the enumeration information includes the one or more attributes; and

determining whether each of the one or more attributes has the predetermined value.

13. A host device comprising:

a processor; and

a memory device coupled to the processor,

wherein the processor is configured to;

receive from an USB accessory coupled to the host device, enumeration information identifying a plurality of interfaces supported by the USB accessory, the plurality of interfaces including a master interface that has one or more associated attributes;

determine whether the enumeration information indicates presence of the one or more attributes associated with the master interface; and

in the event that the enumeration information indicates presence of the one or more attributes associated with the master information;

obtain authentication information from the USB accessory in accordance with a protocol associated with the master interface; and

determine, based on the authentication information, whether the USB accessory is authorized to communicate with the host device; and

in the event that the accessory is authorized, permit communication with the USB accessory using one or more interfaces from among the plurality of interfaces identified as being supported by the accessory.

14. The host device of claim 13 wherein the one or more attributes each has a predetermined value;

and

wherein the processor is further configured to verify whether each of the one or more attributes indicated in the enumeration information has the predetermined value.

15. The host device of claim 13 wherein the processor is further configured to enable a first set of interfaces, from among the one or more interfaces supported by the USB accessory, based on the authentication information.

16. The host device of claim 13 wherein the processor is further configured to:

extract a digital certificate from the authentication information;

validate the digital certificate; and

enable the USB accessory for use with the host device if the validation is successful.

17. A method for operating an accessory, the method comprising:

providing, to a host device, a list of one or more interfaces supported by the accessory, the list of interfaces including a master interface;

receiving a request from the host device to provide authentication information via a protocol associated with the master interface;

providing the authentication information, using the protocol, in response to the request from the host device; and

receiving information from the host device indicating enablement of the one or more interfaces, if the authentication is successful.

18. The method of claim 17 wherein the accessory communicates with the host device using a communication protocol associated with the master interface.

19. The method of claim 17 wherein the request for providing the authentication information includes a random number generated by the host device.

20. The method of claim 17 wherein the authentication information comprises one of a device identifier, a version indicator, and a digital certificate.

21. The method of claim 17 wherein the accessory is a universal serial bus (USB) accessory.

22. The method of claim 21 wherein the list of one or more interfaces is provided as part of a USB enumeration process.