Security for software defined radio terminals

• US 8,977,852 B2
• Filed: 06/18/2007
• Issued: 03/10/2015
• Est. Priority Date: 06/18/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kallin, Harald, Almgren, Magnus, Nslund, Mats, Selander, Gran
• Primary Examiner(s): Vostal, O. C.
• Application Number:
  US12/601,569
• Publication Number:
  US 20100146274A1
• Time in Patent Office: 2,822 Days
• Field of Search: 713/168
• US Class Current: 713/168
• CPC Class Codes: H04L 2463/061 applying further key derivation, e.g. deriving traffic keys from a pair-wise master key cryptographic mechanisms or cryptographic arrangements for generation of secret information including derivation or calculation of cryptographic keys or passwords H04L9/0861
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 63/123 received data contents, e.g. message integrity
• CPC Class Codes: H04L 9/06 the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
• CPC Class Codes: H04L 9/08 Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords network architectures or network communication protocols for supporting key management in a packet data network H04L63/06
• CPC Class Codes: H04L 9/32 including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 12/10 Integrity
• CPC Class Codes: H04W 12/35 Protecting application or service provisioning, e.g. securing SIM application provisioning
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A module (2) for integrity protection of messages transmitted from a mobile software defined radio (SDR) terminal (1), the module provided with a confined cryptographic key K and arranged to receive loaded SDR-code. The module derives an integrity protecting key Rk from at least said cryptographic key K, and provides a periodic integrity protection on-line of generated messages using said key integrity protecting key Rk, and the integrity of said messages is verified by an integrity checking node (10) of the access network.

Claims

1. An SDR-protecting module for an SDR terminal, wherein the SDR-protecting module is provided with a confined cryptographic key K and configured to:

receive loaded SDR-code,

derive an integrity-protecting key Rk at least from;

(1) the confined cryptographic key K, and

(2) one or more of;

(a) a value based on a security key of a subscriber identity module of the SDR terminal, and

(b) a value based on at least part of the loaded SDR-code; and

provide integrity protection of one or more SDR functionality messages using the integrity-protecting key Rk, wherein integrity of the SDR functionality messages is verified by an integrity-checking node in an access network using the integrity-protecting key Rk derived by the access network from K.

2. The SDR-protecting module of claim 1, wherein the integrity-checking node is configured to receive the integrity-protecting key Rk from a key generating server of a home network by AAA signaling, and the key generating server is arranged to derive the integrity-protecting key Rk from at least the cryptographic key K.

3. The SDR-protecting module of claim 1, wherein the integrity-checking node is configured to derive the integrity-protecting key Rk from input values received from a home network of the SDR terminal, wherein at least one of the input values is dependent on the cryptographic key K.

4. The SDR-protecting module of claim 1, wherein a copy of the cryptographic key K is stored in a terminal register unit in a home network of the SDR terminal.

5. The SDR-protecting module of claim 1, wherein the SDR functionality messages comprises radio signal measurement reports.

6. The SDR-protecting module of claim 1, wherein the integrity protection comprises:

a control plane signal-generating unit calculating a message-authenticating checksum, for an SDR functionality message, using the integrity-protecting key Rk; and

adding the message-authenticating checksum to the message before transmission.

7. The SDR-protecting module of claim 1, wherein the SDR functionality messages are associated with an RRC layer.

8. The SDR-protecting module of claim 1, wherein the SDR functionality messages are associated with a MAC layer.

9. The SDR-protecting module of claim 1, wherein the SDR-protecting module is configured to receive SDR-code loaded directly from an SDR code storage and to verify correctness of the loaded SDR-code.

10. The SDR-protecting module of claim 9, wherein the module is configured to inactivate a control plane signal-generating unit in response to determining that the loaded SDR-code is incorrect.

11. The SDR-protecting module of claim 9, wherein the value based on at least part of the loaded SDR-code corresponds to a checksum of the loaded SDR-code.

12. The SDR-protecting module of claim 11, wherein calculating the checksum and deriving the integrity-protecting key Rk, is repeated periodically.

13. The SDR-protecting module of claim 11, wherein the checksum is dependent on a portion of the loaded SDR-code associated with the RRC layer.

14. The SDR-protecting module of claim 11, wherein the checksum is dependent on a portion of the loaded SDR-code associated with the MAC layer.

15. The SDR-protecting module of claim 1, wherein the integrity-protecting key Rk is further derived from a random nonce.

16. The SDR-protecting module of claim 1, wherein the SDR-protecting module provides an execution environment for at least a part of RRC signaling and processing.

17. The SDR-protecting module of claim 1, wherein the module is implemented at least partly as a hardware module.

18. The SDR-protecting module according to claim 1, wherein the confined cryptographic key K is not available outside of the SDR-protecting module.

19. An SDR terminal comprising at least one SDR-protecting module wherein:

the SDR-protecting module is provided with a confined cryptographic key K and configured to;

receive loaded SDR-code;

derive an integrity-protecting key Rk based on at least;

(1) the confined cryptographic key K, and

(2) one or more of;

(a) a value based on a security key of a subscriber identity module of the SDR terminal, and

(b) a value based on at least part of the loaded SDR-code; and

provide integrity protection of one or more SDR functionality messages using the integrity-protecting key Rk, wherein integrity of the SDR functionality messages is verified by an integrity-checking node in an access network using the integrity-protecting key Rk derived by the access network from K.

20. The SDR terminal according to claim 19, wherein the confined cryptographic key K is not available outside of the SDR-protecting module.

21. A method of protecting integrity of SDR-functionality software by using an SDR-protecting module provided with a confined cryptographic key K, the method comprising:

the SDR-protecting module receiving loaded SDR-code;

the SDR-protecting module deriving an integrity-protecting key Rk based on at least;

(1) the cryptographic key K, and

(2) one or more of;

(a) a value based on a security key of a subscriber identity module of the SDR terminal, and

(b) a value based on at least part of the loaded SDR-code; and

the SDR-protecting module providing integrity protection of one or more SDR functionality messages using the derived integrity-protecting key Rk, wherein integrity of the SDR functionality messages is verified by an integrity-checking node in an access network using the integrity-protecting key Rk derived by the access network from K.

22. The method of claim 21, wherein the integrity protecting key Rk is further derived from at least a random nonce.

23. The method of claim 21, wherein the SDR-protecting module receives SDR-code loaded directly from an SDR code storage and verifies correctness of the loaded SDR-code.

24. The method of claim 21, wherein the value based on at least part of the loaded SDR-code corresponds to a checksum of the loaded SDR-code.

25. The method of claim 24, wherein the checksum of the loaded SDR-code is periodically recalculated and the integrity-protecting key Rk is recalculated using the recalculated checksum.

26. The method of claim 24, wherein the checksum is based on a portion of the loaded SDR-code associated with an RRC layer.

27. The method of claim 24, wherein the checksum is based on a portion of the loaded SDR-code associated with a MAC layer.

28. The method of claim 21, wherein the integrity-checking node further determines a correlation between RRC signal reports of bad reception and TCP ACKNOWLEDGEMENTS relating to an SDR terminal.

29. The method of claim 21, wherein the integrity-checking node receives the integrity-protecting key Rk from a key-generating server in a home network by AAA signaling.

30. The method of claim 29, wherein the key-generating server derives the integrity-protecting key Rk from a copy of the cryptographic key K stored in a terminal register unit in the home network.

31. The method of claim 30, wherein the key-generating server further derives the integrity-protecting key Rk from a copy of the loaded SDR-code stored in the terminal register unit.

32. The method of claim 30, wherein the key-generating server further derives the integrity-protecting key Rk from a copy of a key from a SIM or USIM stored in an HLR/AuC or a HSS of the home network.

33. The method of claim 21, wherein the integrity-checking node derives the integrity-protecting key Rk from input values received from a home network, wherein at least one of the input values is dependent on the cryptographic key K.

34. The method of claim 21, wherein a home network transfers, to an access network, information indicating an SDR-code version.

35. The method of claim 21, the method further comprising:

the SDR-protecting module performing an SDR-module authenticating procedure to verify the presence of the SDR-protecting module, wherein the authenticating procedure comprises using information dependent on a copy of the confined cryptographic key K obtained from a terminal register unit of a home network.

36. The method of claim 21, wherein the SDR functionality messages comprise a radio signal measurement reports.

37. The method of claim 21, wherein the integrity protection comprises:

a control plane signal-generating unit computing a message-authenticating checksum, for an SDR functionality message, using the integrity-protecting key Rk, and

adding the authenticating checksum to the SDR functionality message before transmission.

38. The method of claim 37, wherein the integrity-checking node verifies a received SDR functionality message by:

calculating a checksum of the message using the integrity-protecting key Rk and comparing the calculated checksum to the message authenticating checksum added to the message.

39. The method of claim 38, wherein the access network disconnects the mobile terminal in response to determining that the compared checksums do not correspond.

40. The method of claim 21, wherein the SDR functionality messages are associated with an RRC layer.

41. The method of claim 21, wherein the SDR functionality messages are associated with a MAC layer.

42. The method of claim 37, further comprising:

the SDR-protecting module deactivating the control plane signal-generating unit in response to determining that the loaded SDR-code is incorrect.

43. The method according to claim 21, wherein the confined cryptographic key K is not available outside of the SDR-protecting module.