SECURE TELEMETRIC LINK

• US 20120330380A1
• Filed: 09/04/2012
• Published: 12/27/2012
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Corndorf, Eric D.
• Granted Patent: US 9,960,916 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: G06F 7/582 Pseudo-random number generators
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 2209/88 Medical equipments
• CPC Class Codes: H04L 9/0631 Substitution permutation network [SPN], i.e. cipher composed of a number of stages or rounds each involving linear and nonlinear transformations, e.g. AES algorithms
• CPC Class Codes: H04L 9/0637 Modes of operation, e.g. cipher block chaining [CBC], electronic codebook [ECB] or Galois/counter mode [GCM]
• CPC Class Codes: H04L 9/0844 with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/3234 involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853

Abstract

A communications protocol is used to provide data privacy, message integrity, message freshness, and user authentication to telemetric traffic, such as to and from implantable medical devices in a body area network. In certain embodiments, encryption, message integrity, and message freshness are provided through use of token-like nonces and ephemeral session-keys derived from device identification numbers and pseudorandom numbers.

Claims

1. A medical device adapted for implantation comprising:

a memory configured to store a key used to secure communications within a wireless network;

a transceiver module configured to wirelessly communicate with a second device within the wireless network; and

a sensor configured to detect close proximity of the second device;

wherein the medical device is configured to transmit the key wirelessly in response to the sensor detecting close proximity of the second device.

2. The medical device of claim 1, wherein the sensor comprises a near-field magnetic sensor configured to detect the presence of a magnet and the medical device is configured to transmit the key wirelessly in response to the near-field magnetic sensor detecting the magnet.

3. The medical device of claim 2, wherein the near-field magnetic sensor comprises one of a magnetic reed switch and Hall-effect sensor.

4. The medical device of claim 1, wherein the key may be a temporary key that is only valid for the duration of a telemetry session.

5. The medical device of claim 1, wherein the key comprises a first key and the memory is configured to store a second, temporary key, wherein the medical device is configured to require additional credentials to transmit the first key compared to the credentials to transmit the second, temporary key.

6. The medical device of claim 5, wherein the medical device is configured to transmit the second, temporary key in response the sensor detecting close proximity of the second device for a first period of time and to transmit the first key in response the sensor detecting close proximity of the second device for a second period of time, wherein the second period of time is longer than the first period of time.

7. The medical device of claim 1, wherein the transceiver transmits the key at a reduced RF transmission power in response to the sensor detecting close proximity of the second device.

8. The medical device of claim 1, wherein the medical device is configured to be in a locked state in which the medical device does not transmit the key in response to the output of the sensor and to transition to an unlocked state in response to a request from the second device wherein in the unlocked state the medical device does transmit the key in response to the output of the sensor.

9. The medical device of claim 8, wherein the medical device transitions back to the locked state when the sensor does not detect close proximity of the second device within a predetermined period of time of transitioning to the unlocked state.

10. The medical device of claim 1, wherein the key comprises one a network key and a session key.

11. A method comprising:

storing a key used to secure communications within a wireless network;

detecting close proximity of a second device within the wireless network;

wirelessly transmitting the key to the second device in response to detecting close proximity of the second device.

12. The method of claim 11, wherein detecting close proximity of a second device within the wireless network comprises detecting the presence of a magnet.

13. The method of claim 11, wherein wirelessly transmitting the key comprises wirelessly transmitting a temporary key that is only valid for the duration of a telemetry session.

14. The method of claim 11, wherein the key comprises a first key and the method further comprises:

storing a second, temporary key;

transmitting the first key in response to a first set of credentials; and

transmitting the second, temporary key in response to a second set of credentials, wherein the first set of credentials includes additional credentials to compared to the second set of credentials.

15. The method of claim 14, wherein the first set of credentials comprises detecting close proximity of the second device for a first period of time and the second set of credentials comprises detecting close proximity of the second device for a second period of time, wherein the first period of time is longer than the second period of time.

16. The method of claim 11, further comprising reducing the RF transmission power in response to detecting close proximity of the second device and transmitting the key at the reduced RF transmission power.

17. The method of claim 11, further comprising:

locking the medical device such that the medical device does not transmit the key in response to detecting close proximity of the second device; and

unlocking the medical device in response to a request from the second device, wherein the medical device transmits the key in response to detecting close proximity of the second device when unlocked.

18. The method of claim 17, further comprising locking the medical device again in response to not detecting close proximity of the second device within a predetermined period of time after unlocking the medical device.

19. The method of claim 11, wherein the key is one of a network key or a session key.