Secure optical communication channel for implantable medical devices

1. An implantable medical device (IMD) configured to communicate with an external device (ED), the ED being configured to support two-way RF communications and having a light source, the IMD comprising:

a processor coupled to an optical detector, the processor being configured to verify that light is being received from the ED light source and that the ED is a trusted device by determining that an intensity of the light being received from the ED light source is above a predetermined threshold, establishing a unidirectional optical channel from the ED to the IMD; and

an RF transceiver coupled to the processor, the processor being configured permit two-way RF communications with the ED only under a condition that the ED is verified as a trusted device,

wherein the processor is further configured to detect a multi-bit message from the ED via the unidirectional optical channel,

wherein the multi-bit message includes a key for use in encrypting and decrypting RF communication with the ED,

wherein the multi-bit message also includes a pre sequence received prior to the key and a post sequence received after the key, and

wherein the processor is further configured to determine the transmission rate of the ED light source based on the pre sequence.

2. The IMD of claim 1 wherein the processor is configured to wake up periodically or aperiodically to check for the presence of light from the ED light source.

3. The IMD of claim 1 wherein the multi-bit message includes data or a command for the IMD.

4. The IMD of claim 1 wherein the ED is configured to transmit the multi-bit message using a modulation scheme.

5. The IMD of claim 4 wherein the modulation scheme includes at least one of on-off keying (OOK), frequency-shift keying (FSK), amplitude-shift keying (ASK), amplitude and phase-shift keying (APSK), continuous phase modulation (CPM) and pulse-position modulation (PPM).

6. The IMD of claim 1 wherein following verification that the ED is a trusted device the processor is configured to support encrypted communication via the RF transceiver using the key obtained via the unidirectional optical channel.

7. The IMD of claim 6 wherein the processor is configured to generate a confirmation message encrypted using the key, the processor being configured to transmit the confirmation message to the ED via the RF transceiver.

8. The IMD of claim 7 wherein the ED is configured determine whether the confirmation message can be successfully decoded using the key and only under this condition the ED is configured to support subsequent bi-directional RF communications with the IMD encrypted using the key.

9. A method of communicating using an implantable medical device (IMD) configured to communicate with an external device (ED), the ED being configured to support two-way RF communications and having a light source, the method comprising:

providing a processor coupled to an optical detector, the processor being configured to verify that light is being received from the ED light source and that the ED is a trusted device by determining that an intensity of the light being received from the ED light source is above a predetermined threshold, establishing a unidirectional optical channel from the ED to the IMD; and

providing an RF transceiver coupled to the processor, the processor being configured permit two-way RF communications with the ED only under a condition that the ED is verified as a trusted device,

wherein the processor is further configured to detect a multi-bit message from the ED via the unidirectional optical channel,

wherein the multi-bit message includes a key for use in encrypting and decrypting RF communication with the ED,

wherein the multi-bit message also includes a pre sequence received prior to the key and a post sequence received after the key, and

wherein the processor is further configured to determine the transmission rate of the ED light source based on the pre sequence.

10. The method of claim 9 wherein the processor is configured to wake up periodically or aperiodically to check for the presence of light from the ED light source.

11. The method of claim 9 wherein the multi-bit message includes data or a command for the IMD.

12. The method of claim 9 wherein the ED is configured to transmit the multi-bit message using a modulation scheme.

13. The method of claim 12 wherein the modulation scheme includes at least one of on-off keying (OOK), frequency-shift keying (FSK), amplitude-shift keying (ASK), amplitude and phase-shift keying (APSK), continuous phase modulation (CPM) and pulse-position modulation (PPM).

14. The method of claim 9 wherein following verification that the ED is a trusted device the processor is configured to support encrypted communication via the RF transceiver using the key obtained via the unidirectional optical channel.

15. The method of claim 14 wherein the processor is configured to generate a confirmation message encrypted using the key, the processor being configured to transmit the confirmation message to the ED via the RF transceiver.

16. The method of claim 15 wherein the ED is configured determine whether the confirmation message can be successfully decoded using the key and only under this condition the ED is configured to support subsequent bi-directional RF communications with the IMD encrypted using the key.

17. The method of claim 9 , wherein the ED light source is a light on a smartphone held no more than 1.5 cm from the IMD.

18. The method of claim 9 , wherein the transmission rate is half the duration of a time frame in which the IMD detects the pre sequence.