Traffic preemption system signal validation method
A secure optical-communication traffic-preemption system and method is provided that securely communicates an identification code from an optical emitter to a traffic location. The optical emitter transmits light pulses that represent an encrypted code that is an encryption using a time-varying encryption key of at least an identification code. An optical detector situated at a traffic location receives the transmitted light pulses. Validation, including decryption using a time-varying decryption key, is attempted for the encrypted identification code represented within the received light pulses. In response to validating the included identification code, a traffic-preemption command is generated for a traffic light at the traffic location.
1. A secure optical-communication traffic-preemption system, comprising;
an optical emmitter adapted to transmit light pulses that represent an encrypted code that is an encryption using a time-varying encryption key of at least an identification code; and
a traffic light circuit having
an optical detector located at a traffic location and adapted to receive the transmitted light pulses, and
a decoding circuit adapted to respond to the received light pulses by attempting to validate the included identification code and, in response to validating the included identification code, generate a traffic-preemption command for a traffic light at the traffic location.
2. The traffic-preemption system of claim 1 , wherein the decoding circuit is further adapted to use a decryption key to recover the identification code.
3. The traffic-preemption system of claim 1 , wherein the encrypted code is a function of a pseudo-random sequence generated from the time-varying encryption key.
4. The traffic-preemption system of claim 3 , wherein the light pules further represent a position in a repeating cycle of the pseudo-random sequence.
5. The traffic-preemption system of claim 3 , wherein the time-varying encryption key changes as a function of a natural parameter.
6. The traffic-preemption system of claim 5 , wherein the natural parameter is time-based.
7. The traffic-preemption system of claim 5 , wherein the natural parameter is algorithmically-based.
8. The traffic-preemption system of claim 1 , wherein the light pulses further represent the identification code.
9. The traffic-preemption system of claim 1 , wherein the decoding circuit is adapted to use a look-up table to validate the identification code.
10. The traffic-preemption system of claim 1 , wherein the decoding circuit is adapted to log the success and failure of the attempt to validate the included identification code.
11. The traffic-preemption system of claim 1 , wherein a key is manually implemented based on a recently-issued administration function, and the decoding circuit is adapted to use decryption based on the key to recover the identification code.
12. The traffic-preemption system of claim 1 , wherein a key is automatically implemented by at least the decoding circuit.
13. The traffic-preemption system of claim 1 , further including an encoding circuit, communicatively coupled to and providing the encrypted code to the optical emitter, wherein the time-varying encryption key is a time-varying symmetric key that is
manually implemented by the encoding circuit based on a recently-issued administration function, and
automatically implemented by and used by the decoding circuit to recover the identification code.
14. The traffic-preemption system of claim 13 , wherein the time-varying symmetric key is automatically implemented by and used by the decoding circuit both to recover the identification code and to alter a manner in which the decoding circuit recovers the identification code.
15. The traffic-preemption system of claim 1 , wherein the decoding circuit is further adapted to recover the identification code using two values for a decryption key that correspond to two successive values of the time-varying encryption key.
16. The traffic-preemption system of claim 1 , wherein the optical emitter is mounted to a vehicle and the identification code is a vehicle identification code associated with the vehicle.
17. A detection arrangement of an optical-communication traffic-preemption system, comprising:
an optical detector located at a traffic location and adapted to receive transmitted light pulses from an optical emitter, the transmitted light pulses including an operation identification code that is encrypted using a time-varying encryption key; and
a validation circuit coupled to the optical detector, the validation circuit adapted to store a time-varying decryption key, decrypt using the time-varying decryption key the operation identification code that is encrypted, and attempt to validate the operation identification code.
18. The detection arrangement of claim 17 , wherein the operation identification code is a vehicle identification code and the validation circuit is further adapted to generate a phase request for traffic preemption at the traffic location in response to validating the vehicle identification code.
19. The detection arrangement of claim 17 , wherein the operation identification code is a key download command and the validation circuit is further adapted to update the time-varying decryption key stored in the validation circuit in response to validating the key download command.
20. The detection arrangement of claim 17 , wherein the validation circuit is further adapted to update the time-varying decryption key by one of wired telephone connection, wireless telephone connection, wired internet access, and wireless internet access.
21. A method for securely communicating an operation identification code to a traffic location in an optical-communication traffic-preemption system, comprising:
encrypting the operation identification code using a time-varying encryption key;
transmitting light pulses from an optical emitter, wherein the light pulses represent the operation identification code that is encrypted;
receiving the light pulses at an optical detector situated at the traffic location;
decrypting using a time-varying decryption key the received operation identification code that is encrypted; and
validating the operation identification code that is decrypted.
22. The method of claim 21 , further comprising issuing a preemption command for a traffic light at the traffic location in response to the validation of the operation identification code that is decrypted.
23. The method of claim 22 , wherein the operation identification code includes a vehicle identification code associated with a vehicle to which the optical emitter is mounted.
24. The method of claim 21 , wherein the operation identification code is key download command and the time-varying decryption key is updated in response to the validation of the operation identification code that is decrypted.
25. The method of claim 21 , further comprising logging the success and failure of the validation of the operation identification code that is decrypted.
26. A secure optical-communication traffic-preemption system, comprising:
means for encrypting an operation identification code using a time-varying encryption key;
means for transmitting light pulses from an optical emitter, wherein the light pulses represent the operation identification code that is encrypted;
means for receiving the light pulses at an optical detector situated at the traffic location;
means for decrypting using a time-varying decryption key the received operation identification code that is encrypted; and
means for validating the operation identification code that is decrypted.