Secure authenticated distance measurement
The invention relates to a method for a first communication device to perform authenticated distance measurement between the first communication device and a second communication device, wherein the first and the second communication device share a common secret and the common secret is used for performing the distance measurement between the first and the second communication device. The invention also relates to a method of determining whether data stored on a first communication device are to be accessed by a second communication device. Moreover, the invention relates to a communication device for performing authenticated distance measurement to a second communication device. The invention also relates to an apparatus for playing back multimedia content comprising a communication device.
1. A first device for controlling delivery of protected content to a second device, the first device comprising a processor circuit, the processor circuit arranged to execute instructions, the instructions arranged to:
receive a second device certificate from the second device prior to sending a first signal;
provide the first signal to the second device when the second device certificate indicates that the second device is compliant with at least one compliance rule;
receive a second signal from the second device after providing the first signal; and
provide the protected content to the second device when the second signal is derived from a secret and a time between the providing of the first signal and the receiving of the second signal is less than a predetermined time,
wherein the secret is known by the first device.
2. The first device of claim 1 , wherein the secret is securely provided to the second device by the first device.
3. The first device of claim 2 , wherein determining that the second signal is derived from the secret comprises:
modifying the first signal, wherein the modifying requires the secret; and
determining that the modified first signal is identical to the second signal.
4. The first device of claim 3 wherein the secret comprises a first random number.
5. The first device of claim 4 wherein the secret is encrypted with a public key.
6. The first device of claim 5 wherein the first signal comprises a second random number.
7. The first device of claim 2 , wherein the second signal comprises the first signal modified by the secret.
8. The first device of claim 2 , wherein determining that the second signal is derived from the secret comprises:
modifying the second signal, wherein the modifying requires the secret; and
determining that the modified second signal is identical to the first signal.
9. The first device of claim 1 , wherein determining that the second signal is derived from the secret comprises:
modifying the first signal, wherein the modifying requires the secret; and
determining that the modified first signal is identical to the second signal.
10. The first device of claim 1 , wherein the predetermined time is based on a communication system associated with the first device.
11. The first device of claim 1 , further comprising instructions arranged to provide the secret to the second device.
12. The first device of claim 1 , wherein the second signal comprises the first signal modified by the secret.
13. The first device of claim 1 wherein the secret comprises a random number.
14. The first device of claim 1 wherein the secret is encrypted with a public key.
15. The first device of claim 1 wherein the first signal comprises a random number.
16. The first device of claim 1 , wherein the second signal comprises an XOR operation of the first signal with the secret.
17. The first device of claim 1 , further comprising instructions arranged to receive the secret from the second device.
18. The first device of claim 1 , wherein determining that the second signal is derived from the secret comprises:
modifying the second signal, wherein the modifying requires the secret; and
determining that the modified second signal is identical to the first signal.
19. A method of controlling delivery of protected content from a first device to a second device, the first device comprising a processor circuit the processor circuit arranged to execute instructions implementing the method, the method comprising:
receiving a second device certificate from the second device prior to sending a first signal;
providing the first signal to the second device when the second device certificate indicates that the second device is compliant with at least one compliance rule;
receiving a second signal from the second device after providing the first signal;
sending the protected content from the first device to the second device when the second signal is derived from the secret and a time between the providing of the first signal and the receiving of the second signal is less than a predetermined time,
wherein the secret is known by the first device.
20. The method of claim 19 , wherein the secret is securely provided to the second device by the first device.
21. The method of claim 20 , wherein determining that the second signal is derived from the secret comprises:
modifying the first signal according to the secret; and
determining that the modified first signal is identical to the second signal.
22. The method of claim 21 , wherein the secret comprises a first random number.
23. The method of claim 22 , wherein the secret is encrypted with a public key.
24. The method of claim 23 , wherein the first signal comprises a second random number.
25. The method of claim 20 , wherein the second signal comprises the first signal modified by the secret.
26. The method of claim 20 , wherein determining that the second signal is derived from the secret comprises:
modifying the second signal according to the secret; and
determining that the modified second signal is identical to the first signal.
27. The method of claim 19 , wherein determining that the second signal is derived from the secret comprises:
modifying the first signal according to the secret; and
determining that the modified first signal is identical to the second signal.
28. The method of claim 19 , wherein the predetermined time is based on a communication system associated with the first device.
29. The method of claim 19 , further comprising providing the secret to the second device.
30. The method of claim 19 , wherein the second signal comprises the first signal modified by the secret.
31. The method of claim 19 , wherein the secret comprises a random number.
32. The method of claim 19 , wherein the secret is encrypted with a public key.
33. The method of claim 19 , wherein the first signal comprises a random number.
34. The method of claim 19 , wherein the second signal comprises an XOR operation of the first signal with the secret.
35. The method of claim 19 , further comprising instructions arranged to receive the secret from the second device.
36. The method of claim 19 , wherein determining that the second signal is derived from the secret comprises:
modifying the second signal according to the secret; and
determining that the modified second signal is identical to the first signal.