Generating secure device secret key
Methods, devices, systems and computer program products are provided to facilitate cryptographically secure retrieval of secret information that is embedded in a device. The embedded secret information can include a random number that is not custom-designed for any specific requestor of the secret information. Upon receiving a request for the embedded secret information, an encrypted secret is provided to the requestor that enables the recovery of the embedded secret information by only the requestor. Moreover, a need for maintenance of a database of the embedded secret information and the associated requestors is eliminated.
1. A method in a device for securely exporting key material to a requesting device, comprising:
receiving, at the device, a message from a first requestor for key material for the device, wherein the message includes a public key associated with the first requester and a digital signature of the public key associated with the first requestor generated using a public key associated with the device;
determining whether the requested key material has been previously exported to the first requestor;
when the requested key material has not been previously exported to the first requestor:
generating the key material using secret information for the device; and
exporting the key material to the first requestor.
2. The method of claim 1 , wherein:
the device further comprises a device identifier; and
the device identifier is provided to the first requestor with the key material.
3. The method of claim 1 , wherein
the message further includes an identifier of the first requestor; and
the key material is generated by encrypting the identifier of the first requestor using the secret information, and then encrypting the result of the encryption of the identifier of the first requestor using the received public key.
4. The method of claim 3 , further comprising:
receiving a second message from a second requestor for key material for the device, wherein the second message includes an identifier for the second requester; and
generating a second key material by encrypting the identifier for the second requestor using the secret information, and then encrypting the result of the encryption of the identifier for the second requestor using the second requestor's received public key.
5. The method of claim 1 , further comprising digitally signing the key material using the private key of the device.
6. The method of claim 1 , wherein the secret information comprises a random number that is embedded within the device as part of a manufacturing process of the device.
7. The method of claim 6 , wherein the random number is a cryptographically secure random number that is generated outside of the device.
8. The method of claim 1 , wherein the message comprises a usage flag indicative of a particular operation of the device.
9. The method of claim 8 , further comprising:
storing the received usage flag:
using the stored usage flag to control access to the device by the first requestor.
10. The method of claim 1 , further comprising:
storing a private key associated with the device, wherein the private key is related to the public key of the device.
11. The method of claim 10 , further comprising verifying the digital signature using the private key of the device, wherein the key material is generated only if verification of the received digital signature is successful.
12. The method of claim 1 , further comprising:
storing an indication that the key material was exported to the first requestor after the key material is exported to the first requestor.
13. The method of claim 1 , further comprising:
storing the secret information in the device.
14. The method of claim 13 , further comprising:
programming a one-time programmable memory in the device with the secret information.
15. The method of 13 , wherein the key material is generated by encrypting the secret information using the received public key.
16. A device for securely exporting key material to a requesting device, comprising:
a processor configured to:
receive a message from a first requestor for key material for the device, wherein the message includes a public key associated with the first requester and a digital signature of the public key associated with the first requestor generated using a public key associated with the device,
determine whether the requested key material has been previously exported to the first requestor,
when the requested key material has not been previously exported to the first requestor:
generate the key material using secret information for the device, and
export the key material to the first requestor; and
a memory configured to store the secret information and a private key for the device.
17. The device of claim 16 , wherein the processor is further configured to generate the key material by encrypting the secret information using the received public key.
18. The device of claim 16 , wherein the memory is further configured to store a device identifier.