Medical device communication using encryption based on correlated motion

• US 9,185,087 B2
• Filed: 10/24/2013
• Issued: 11/10/2015
• Est. Priority Date: 10/24/2013
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Carlson, Timmothy S., Bourget, Duane L.
• Primary Examiner(s): Song, Hosuk
• Application Number:
  US14/062,223
• Publication Number:
  US 20150117645A1
• Time in Patent Office: 747 Days
• Field of Search: 380/44, 380/255, 380/262, 380/270, 713168-169, 713/189, 713/193, 607/57, 607/60
• US Class Current: 1/1
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61N 1/36128 Control systems
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• CPC Class Codes: G16H 40/63 for local operation
• 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 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 9/0838 Key agreement, i.e. key establishment technique in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these network architectures or network communication protocols for key exchange in a packet data network H04L63/061
• CPC Class Codes: H04L 9/0872 using geo-location information, e.g. location data, time, relative position or proximity to other entities
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 12/50 Secure pairing of devices
• CPC Class Codes: H04W 12/68 Gesture-dependent or behaviour-dependent

Abstract

Devices, systems, and techniques for generating an encryption key using detected motion from a device. In one example, a method may include receiving movement information indicative of motion detected by a first device during a period of time in which the first device and a second device were bumped together, determining a set of values that represent at least one characteristic of the movement information, and generating, based on the set of values, an encryption key for at least one of encrypting and decrypting data communicated between the first device and the second device. In some examples, the first device may include a sensor configured to detect each time the first device is bumped with the second device during the period of time. The first and second devices may be an implantable medical device and a programmer for the implantable medical device.

Claims

1. A method comprising:

receiving, by one of one or more processors of a first device or one or more processors of a networked server, movement information indicative of motion detected by the first device during a period of time in which the first device and a second device were bumped together;

determining, by one of the one or more processors of the first device or the one or more processors of the networked server, a set of values that represent at least one characteristic of the movement information; and

generating, by the one or more processors of the first device and based on the set of values, an encryption key for at least one of encrypting or decrypting data communicated between the first device and the second device.

2. The method of claim 1, wherein the at least one characteristic comprises one or more amplitudes of an acceleration signal of the movement information.

3. The method of claim 1, wherein the at least one characteristic comprises one or more time periods between respective supra-threshold amplitude peaks of an acceleration signal of the movement information.

4. The method of claim 1, wherein the characteristic comprises a frequency spectrum of an acceleration signal of the movement information.

5. The method of claim 1, wherein determining the set of values comprises:

segmenting the period of time into a plurality of time slots;

for each of the plurality of time slots, comparing an amplitude of an acceleration signal of the movement information to an amplitude threshold;

assigning a first value to each of the plurality of time slots in which the amplitude of the acceleration signal exceeds the amplitude threshold;

assigning a second value to each of the plurality of time slots in which the amplitude of the acceleration signal does not exceed the amplitude threshold; and

ordering the first and second values according to a chronological sequence of the time slots to create the set of values.

6. The method of claim 1, wherein determining the set of values comprises:

comparing an amplitude of an acceleration signal of the movement information to a plurality of different amplitude thresholds, wherein each of the plurality of different amplitude thresholds corresponds to a respective value;

for each amplitude peak of the acceleration signal exceeding at least one of the plurality of different amplitude thresholds, assigning, to the amplitude peak, the respective value corresponding to the highest amplitude threshold exceeded by the respective amplitude peak; and

ordering the assigned values according to the chronological occurrence of the respective amplitude peaks during the period of time to create the set of values.

7. The method of claim 1, wherein determining the set of values comprises:

comparing an amplitude of an acceleration signal of the movement information to an amplitude threshold;

for each pair of amplitude peaks of the acceleration signal exceeding the amplitude threshold, calculating a respective time duration between the pair of amplitude peaks;

matching each of the respective time durations to one of a plurality of duration ranges, wherein each of the plurality of duration ranges corresponds to a respective value;

assigning, based on the matching, the corresponding value of the matching duration range to the respective time durations; and

ordering the assigned values according to the chronological occurrence of the respective time durations during the period of time to create the set of values.

8. The method of claim 1, further comprising:

detecting, by a sensor of the first device, the motion of the first device during the period of time; and

generating, based on the detection, the movement information.

9. The method of claim 1, further comprising:

receiving a request to initiate communication between the first device and the second device;

outputting, for display, a command instructing a user to perform a bump sequence between the first device and the second device, wherein the bump sequence includes one or more physical bumps of the first device against the second device; and

responsive to receiving the movement information indicative of the bump sequence, determining the set of values.

10. The method of claim 1, wherein the first device is an external medical device programmer and wherein the second device is an implantable medical device.

11. The method of claim 1, further comprising:

applying, by the first device, the encryption key to a set of data to generate an encrypted data set; and

transmitting, by the first device, the encrypted data set to the second device.

12. The method of claim 1, further comprising:

receiving, by the first device, an encrypted data set from the second device; and

applying, by the first device, the encryption key to the encrypted data set to decrypt a set of data.

27. The method of claim 1, further comprising storing the encryption key in a memory of the first device.

28. The method of claim 1, wherein the first device is an implantable medical device, and wherein the second device is an external medical device programmer.

29. The method of claim 1, wherein:

receiving movement information indicative of motion detected by the first device during the period of time in which the first device and the second device were bumped together comprises receiving, by the one or more processors of the networked server, movement information indicative of motion detected by the first device during the period of time in which the first device and the second device were bumped together,

determining the set of values that represent at least one characteristic of the movement information comprises determining, by the one or more processors of the networked server, the set of values that represent at least one characteristic of the movement information, and

wherein the method further comprises transmitting, by the networked server, the set of values to the first device.

30. The method of claim 1, wherein the encryption key is a first encryption key that matches a second encryption key generated by the second device.

13. A first device comprising:

one or more processors configured to;

receive movement information indicative of motion detected by the first device during a period of time in which the first device and a second device were bumped together;

determine a set of values that represent at least one characteristic of the movement information; and

generate, based on the set of values, an encryption key for at least one of encrypting or decrypting data communicated between the first device and the second device.

14. The first device of claim 13, wherein the at least one characteristic comprises one or more amplitudes of an acceleration signal of the movement information.

15. The first device of claim 13, wherein the at least one characteristic comprises one or more time periods between respective supra-threshold amplitude peaks of an acceleration signal of the movement information.

16. The first device of claim 13, wherein the characteristic comprises a frequency spectrum of an acceleration signal of the movement information.

17. The first device of claim 13, wherein, to determine the set of values, the one or more processors are configured to:

segment the period of time into a plurality of time slots;

for each of the plurality of time slots, compare an amplitude of an acceleration signal of the movement information to an amplitude threshold;

assign a first value to each of the plurality of time slots in which the amplitude of the acceleration signal exceeds the amplitude threshold;

assign a second value to each of the plurality of time slots in which the amplitude of the acceleration signal does not exceed the amplitude threshold; and

order the first and second values according to a chronological sequence of the time slots to create the set of values.

18. The first device of claim 13, wherein, to determine the set of values, the one or more processors are configured to:

compare an amplitude of an acceleration signal of the movement information to a plurality of different amplitude thresholds, wherein each of the plurality of different amplitude thresholds corresponds to a respective value;

for each amplitude peak of the acceleration signal exceeding at least one of the plurality of different amplitude thresholds, assign, to the amplitude peak, the respective value corresponding to the highest amplitude threshold exceeded by the respective amplitude peak; and

order the assigned values according to the chronological occurrence of the respective amplitude peaks during the period of time to create the set of values.

19. The first device of claim 13, wherein, to determine the set of values, the one or more processors are configured to:

compare an amplitude of an acceleration signal of the movement information to an amplitude threshold;

for each pair of amplitude peaks of the acceleration signal exceeding the amplitude threshold, calculate a respective time duration between the pair of amplitude peaks;

match each of the respective time durations to one of a plurality of duration ranges, wherein each of the plurality of duration ranges corresponds to a respective value;

assign, based on the matching, the corresponding value of the matching duration range to the respective time durations; and

order the assigned values according to the chronological occurrence of the respective time durations during the period of time to create the set of values.

20. The first device of claim 13, further comprising a sensor configured to detect the motion of the first device during the period of time, wherein the one or more processors are configured to generate, based on the detection, the movement information.

21. The first device of claim 13, wherein the one or more processors are configured to:

receive a request to initiate communication between the first device and the second device;

output, for display via a display device, a command instructing a user to perform a bump sequence between the first device and the second device, wherein the bump sequence includes one or more physical bumps of the first device against the second device; and

responsive to receiving the movement information indicative of the bump sequence, determine the set of values.

22. The first device of claim 13, wherein the first device is an external medical device programmer, and wherein the second device is an implantable medical device.

23. The first device of claim 13, wherein the one or more processors are configured to:

apply the encryption key to a set of data to generate an encrypted data set; and

transmit, from the first device, the encrypted data set to the second device.

24. The first device of claim 13, wherein the one or more processors are configured to:

receive an encrypted data set from the second device; and

apply the encryption key to the encrypted data set to decrypt a set of data.

31. The first device of claim 13, further comprising a memory configured to store the encryption key.

32. The first device of claim 13, wherein the first device is an implantable medical device, and wherein the second device is an external medical device programmer.

33. The first device of claim 13, wherein the encryption key is a first encryption key that matches a second encryption key generated by the second device.

25. A non-transitory computer-readable storage medium comprising instructions that cause one or more processors of a first device to:

receive movement information indicative of motion detected by the first device during a period of time in which the first device and a second device were bumped together;

determine a set of values that represent at least one characteristic of the movement information; and

generate, based on the set of values, an encryption key for at least one of encrypting or decrypting data communicated between the first device and the second device.

26. The non-transitory computer-readable storage medium of claim 25, further comprising instructions that cause the one or more processors of the first device to:

receive a request to initiate communication between the first device and the second device;

output, for display, a command instructing a user to perform a bump sequence between the first device and the second device, wherein the bump sequence includes one or more physical bumps of the first device against the second device; and

responsive to receiving the movement information indicative of the bump sequence, determine the set of values.

34. The non-transitory computer-readable storage medium of claim 25, wherein the first device is an external medical device programmer and the second device is an implantable medical device.

35. The non-transitory computer-readable storage medium of claim 25, wherein the first device is an implantable medical device and the second device is an external medical device programmer.

36. A system comprising:

a first device configured to;

generate first movement information indicative of motion detected by the first device during a period of time in which the first device and a second device were bumped together;

determine a first set of values that represent at least one characteristic of the first movement information; and

generate, based on the first set of values, a first encryption key for at least one of encrypting data communicated to the second device or decrypting data received from the second device; and

the second device, wherein the second device is configured to;

generate second movement information indicative of motion detected by the second device during the period of time in which the first device and the second device were bumped together;

determine a second set of values that represent at least one characteristic of the second movement information; and

generate, based on the second set of values, a second encryption key for at least one of encrypting data communicated to the first device or decrypting data received from the first device.

37. The system of claim 36, wherein the first encryption key matches the second encryption key.

38. The system of claim 36, wherein the first device comprises an external medical device programmer, and wherein the second device comprises an implantable medical device.