Device keys

• US 20040146163A1
• Filed: 10/28/2003
• Published: 07/29/2004
• Est. Priority Date: 10/28/2002
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Asokan, Nadarajah, Valtteri, Niemi
• Granted Patent: US 7,920,706 B2
• Time in Patent Office: Days
• US Class Current: 380/277
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 9/0866 involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage

Abstract

A key management of cryptographic keys has a data package including one or more cryptographic keys that are transferred to a personal device 100 from a secure processing point 150 of a device assembly line in order to store device specific cryptographic keys in the personal device 100. In response to the transferred data package, a backup data package is received by the secure processing point 150 from the personal device 100, which backup data package is the data package encrypted with a unique secret chip key stored in a tamper-resistant secret storage 125 of a chip 110 included in the personal device 100. The secure processing point 150 is arranged to store the backup data package, together with an associated unique chip identifier read from the personal device 100, in a permanent, public database 170.

Claims

1. A method for managing cryptographic keys that are specific to a personal device (100), the method being performed at a secure processing point (150) arranged in communication with the personal device, characterised in that the secure processing point performs the steps of:

retrieving a unique chip identifier from a read-only storage (120) of an integrated circuit chip (110) included in the device (100);

storing a data package in the device, the data package including at least one cryptographic key;

receiving, in response to storing the data package, a backup data package from the device (100), which backup data package is the data package encrypted with a unique secret chip key stored in a tamper-resistant secret storage (125) of the chip (100);

associating the unique chip identifier with the received backup data package; and

storing the backup data package and the associated unique chip identifier in a permanent public database (170).

2. The method as claimed in claim 1, wherein the secure processing point performs the further steps of:

associating a unique device identity with the unique chip identifier;

signing the result of said associating step with a manufacturer private signature key corresponding to a manufacturer public signature key stored in a read-only memory of the device, thereby generating a certificate for the unique device identity;

storing the certificate in the device; and

storing the unique device identity and the certificate in association with the backup data package and the unique chip identifier in the permanent public database.

3. The method as claimed in claim 1, wherein the at least one cryptographic key includes at least one key to be used for a secure, key based communication channel between a personal device manufacturer and the personal device.

4. The method as claimed in claim 3, wherein the at least one key to be used for a secure, key based communication channel includes a symmetric key.

5. The method as claimed in claim 4, wherein the symmetric key is generated as a function of a master key and the unique device identity.

6. The method as claimed in claim 3, wherein the at least one key to be used for a secure, key based communication channel includes a private/public key pair.

7. The method as claimed in claim 6, wherein the private/public key pair either is:

generated by the secure processing point during assembly of the device;

or

generated and stored in advance in a secure database before assembly of the device, in which latter case the cryptographic keys stored in advance of assembly are removed from the secret database after reception of the backup data package.

8. The method as claimed in claim 2, wherein the personal device is a wireless communications terminal and the unique device identity is an identifier which identifies the wireless communications terminal in a wireless communications network.

17. A method of recovering a backup data package of a personal device (100), which backup data package has been assembled and stored in accordance with claim 1, the method including the steps of:

reading a unique chip identifier from a read-only storage (120) of the personal device (100);

transmitting the chip identifier to a public database (170);

receiving from the public database the backup data package corresponding to the transmitted chip identifier; and

storing the received backup data package in the personal device.

9. A system for managing cryptographic keys that are specific to a personal device, the system including at least one personal device (100) and a secure processing point (150), which secure processing point is arranged in communication with the personal device, characterised in that:

the device includes an integrated circuit chip (110) with a unique chip identifier in a read-only storage (120) and a unique secret chip key in a tamper-resistant secret storage (125);

the secure processing point includes processing means (155) for retrieving the unique chip identifier and for storing a data package in the device, the data package including at least one cryptographic key;

the device includes processing means (127) for encrypting the received data package with the unique secret chip key and transferring a resulting backup data package back to the secure processing point; and

the processing means of the secure processing point is arranged for storing the received backup data package in association with the unique chip identifier in a permanent public database (170).

10. The system as claimed in claim 9, wherein the processing means (155) of the secure processing point (150) further is arranged for:

associating a unique device identity with the unique chip identifier;

signing the result of the association with a manufacturer private signature key corresponding to a manufacturer public signature key stored in a read-only memory of the device, thereby generating a certificate for the unique device identity;

storing the certificate in the device; and

storing the unique device identity and the certificate in association with the backup data package and the unique chip identifier in the permanent public database.

11. The system as claimed in claim 9, wherein the at least one cryptographic key includes at least one key to be used for a secure, key based communication channel between a personal device manufacturer and the personal device.

12. The system as claimed in claim 11, wherein the at least one key to be used for a secure, key based communication channel includes a symmetric key.

13. The system as claimed in claim 12, wherein the symmetric key is generated as a function of a master key and the unique device identity.

14. The system as claimed in claim 11, wherein the at least one key to be used for a secure, key based communication channel includes a private/public key pair.

15. The system as claimed in claim 14, wherein the the processing means of the secure processing point either is:

arranged for generating the private/public key pair during assembly of the device;

or

arranged for retrieving the private/public key pair from a secure database (140), in which the key pair has been stored in advance before assembly of the device, in which latter case the secure processing point further is arranged for removing the key pair from the secret database after reception of the backup data package.

16. The system as claimed in claim 9, wherein the personal device is a wireless communications terminal and the unique device identity an identifier which identifies the wireless communications terminal in a wireless communications network.

18. A personal device (100) managing cryptographic keys that are specific to the personal device, characterised in that the personal device includes:

an integrated circuit chip (110) with a unique chip identifier in a read-only storage (120) and a unique secret chip key in a tamper-resistant secret storage (125);

processing means (127) for outputting the unique chip identifier;

memory means (130) for storing a received data package including at least one cryptographic key; and

processing means (127) for encrypting the received data package with the unique secret chip key and outputting a resulting backup data package to a permanent public database (170).

19. The personal device as claimed in claim 18, wherein the personal device includes a read-only memory (120) storing a manufacturer public signature key and the memory means (130) is further for storing a received certificate, which corresponds to a certificate stored in association with the backup data package in the public database and which has been signed with a manufacturer private signature key corresponding to the manufacturer public signature key.

20. The personal device as claimed in claim 18, wherein the at least one cryptographic key includes at least one key to be used for a secure, key based communication channel between a personal device manufacturer and the personal device.

21. The personal device as claimed in claim 20, wherein the at least one key to be used for a secure, key based communication channel includes a symmetric key.

22. The personal device as claimed in claim 21, wherein the symmetric key is generated as a function of a master key and the unique device identity.

23. The personal device as claimed in claim 20, wherein the at least one key to be used for a secure, key based communication channel includes a private/public key pair.

24. The personal device as claimed in claim 18, wherein the personal device is a wireless communications terminal and the unique device identity is an identifier which identifies the wireless communications terminal in a wireless communications network.

25. A secure processing point (150) for managing cryptographic keys that are specific to personal devices, the secure processing point being capable of communicating with a personal device (100), characterised in that the secure processing point includes processing means (155) for:

retrieving a unique chip identifier from a read-only storage (120) of an integrated circuit chip (l10) included by the personal device (100);

storing a data package including at least one cryptographic key in the personal device;

receiving an encrypted version of the data package, in the form of a backup data package, from the personal device in response to the stored data package; and

storing the received backup data package in association with the unique chip identifier in a permanent public database (170).

26. The secure processing point as claimed in claim 25, wherein the processing means (155) further is arranged for:

associating a unique device identity with the unique chip identifier;

signing the result of the association with a manufacturer private signature key corresponding to a manufacturer public signature key stored in a read-only memory of the device, thereby generating a certificate for the unique device identity;

storing the certificate in the device; and

storing the unique device identity and the certificate in association with the backup data package and the unique chip identifier in the permanent public database.