Trust Establishment from Forward Link Only to Non-Forward Link Only Devices

A host device for establishing trust with an accessory device, the host device comprising:

• a communication interface for communicating with the accessory device;
• a storage medium;
• and
• a processing circuit coupled to the communication interface and the storage medium, the processing circuit adapted to:
• send a pair request message to an accessory device, the pair request message comprising an identification of a device type of the host device;
• receive a key generator and a random number from the accessory device, the key generator being encrypted using an encryption key derived from the random number and a global key, wherein the global key comprises a value known to the host device that is the same for all devices of a same device type;
• derive the encryption key from the global key and the random number,
• decrypt the key generator using the derived encryption key;
• and
• derive a device key from the key generator and the random number, wherein the device key is employed for establishing secure delivery of content from the accessory device.

A host device for establishing trust with an accessory device, the host device comprising:

• means for sending a pair request message to an accessory device, the pair request message comprising an identification of a device type of the host device;
• means for receiving a key generator and a random number from the accessory device, the key generator being encrypted using an encryption key derived from the random number and a global key, wherein the global key comprises a value known to the host device that is the same for all devices of a same device type;
• means for deriving the encryption key from the global key and the random number;
• means for decrypting the key generator using the derived encryption key;
• and
• means for deriving a device key from the key generator and the random number, wherein the device key is employed for establishing secure delivery of content from the accessory device.

A machine-readable medium comprising instructions executable by a processor for establishing trust between an accessory device and a host device, which instructions cause the processor to:

• send a pair request message to an accessory device, the pair request message comprising an identification of a device type of the host device;
• receive a key generator and a random number from the accessory device, the key generator being encrypted using an encryption key derived from the random number and a global key, wherein the global key comprises a value known to the host device that is the same for all devices of a same device type;
• derive the encryption key from the global key and the random number;
• decrypt the key generator using the derived encryption key;
• and
• derive a device key from the key generator and the random number, wherein the device key is employed for establishing secure delivery of content from the accessory device.

A method operational on an accessory device for establishing trust with a host device, comprising:

• receiving from a host device an indication of a device type of the host device;
• looking up a global key associated with the device type of the host device, the global key comprising a value that is the same for all devices of a same device type;
• generating a random number;
• generating a key generator;
• deriving an encryption key from the global key and the random number;
• sending the key generator and the random number to the host device, the key generator being encrypted with the encryption key;
• and
• deriving a device key from the key generator and the random number, wherein the device key is employed for establishing secure delivery of content to the host device.

An accessory device adapted to establish trust with a host device, the accessory device comprising:

• a first communication interface for receiving communications with a subscriber-based service;
• a second communication interface for communicating with a host device;
• and
• a processing circuit coupled to the first and second communication interfaces, the processing circuit adapted to:
• receive from a host device an indication of a device type of the host device;
• look up a global key associated with the device type of the host device, the global key comprising a value that is the same for all devices of a same device type;
• generate a random number;
• generate a key generator;
• derive an encryption key from the global key and the random number;
• send the key generator and the random number to the host device, the key generator being encrypted with the encryption key;
• and
• derive a device key from the key generator and the random number, wherein the device key is employed for establishing secure delivery of content to the host device.

An accessory device adapted to establish trust with a host device, the accessory device comprising:

• means for receiving from a host device an indication of a device type of the host device;
• means for looking up a global key associated with the device type of the host device, the global key comprising a value that is the same for all devices of a same device type;
• means for generating a random number;
• means for generating a key generator;
• means for deriving an encryption key from the global key and the random number;
• means for sending the key generator and the random number to the host device, the key generator being encrypted with the encryption key;
• and
• means for deriving a device key from the key generator and the random number.

A machine-readable medium comprising instructions executable by a processor for establishing trust between an accessory device and a host device, which instructions cause the processor to:

• receive from a host device an indication of a device type of the host device;
• look up a global key associated with the device type of the host device, the global key comprising a value that is the same for all devices of a same device type;
• generate a random number;
• generate a key generator;
• derive an encryption key from the global key and the random number;
• send the key generator and the random number to the host device, the key generator being encrypted with the encryption key;
• and
• derive a device key from the key generator and the random number.