Streaming implementation of AlphaEta physical layer encryption

1. A method for providing bit-level synchronization and secure resynchronization between a transmitter and a receiver capable of transmitting encrypted data between transmitting and receiving locations, comprising:

transmitting a control data from the transmitter to the receiver;

transmitting an initiation signal from the transmitter to the receiver during an initialization procedure;

enabling a key generator of the transmitter to generate a first running key for use in quantum encryption, the encryption applying an encryption protocol which uses quantum noise to make neighboring M-ary transmission states indistinguishable to an eavesdropper;

using the first running key to encrypt the data at the transmitter and transmitting the quantum encrypted data to the receiver over a communication link;

the quantum encrypted data implements a physical layer encryption protocol that uses a multilevel signal scheme, wherein the multilevel signal is determined by the binary data and a running key;

applying a transmitted data, including the initiation signal to a clock recovery circuit of the receiver to produce a local clock for the receiver;

enabling a key generator of the receiver to generate a second running key at the receiver, the second running key being the same as the first running key;

using the second running key to decrypt the encrypted data at the receiver;

using the initialization signal to synchronize a start of quantum encryption with a start of decryption; and

transmitting a synchronization signal from the receiver to the transmitter over a control channel to start the resynchronization procedure when synchronization is lost.

2. The method according to claim 1 , wherein the initialization signal includes a header and a preamble, and

wherein the initialization signal is transmitted unencrypted.

3. The method according to claim 1 , wherein transmitting an initialization signal includes providing a delay from a start of the transmission of the initialization signal before enabling the key generators at the transmitter and the receiver.

4. The method according to claim 1 , wherein the data to be transmitted is streaming data.

5. The method according to claim 1 , wherein the first and second running keys are generated substantially simultaneously with a reception of data at either the transmitter or receiver.

6. The method according to claim 1 , wherein a shared, multi-bit secret key is extended at the transmitting and receiving locations to produce the first and second running keys, and wherein the shared multi-bit secret key is extended at the receiver substantially simultaneously with reception of the data at the receiver.

7. The method according to claim 1 ,

wherein the clock recovery circuit at the receiver always sees a binary signal.

8. The method according to claim 1 , further comprising using an error estimate from a forward-error correction block to determine when synchronization between the transmitter and the receiver is lost, and transmitting over the control channel an indication of loss of synchronization between the transmitter and the receiver.

9. The method according to claim 1 , wherein the transmitter and the receiver employ an AlphaEta quantum encryption and decryption protocol.

10. The method according to claim 1 , further comprising temporarily storing at least a portion of the data to be transmitted in a buffer storage during the initialization procedure so as to not drop incoming data bits.

11. The method according to claim 1 , wherein the transmitter and the receiver include a loadable key buffer, and further including the steps of

transmitting a fresh key to the transmitter and to the receiver over a key distribution network, and loading the fresh key into the key buffers of the transmitter and the receiver, for subsequent use in generating an extended key.

12. The method according to claim 11 , wherein the encrypted channel remains encrypted continuously, and wherein a timing information on the key change is sent in encrypted form.

13. The method according to claim 1 , wherein a control channel is used to verify that both the transmitter and receiver have identical new keys ready, and wherein once both parties have these keys the transmitter can dynamically load the key into its extended key generator, and wherein the receiver loads the identical key into its extended key generator at a time determined by the timing information sent from the transmitter contained in the control channel thereby allowing for a seamless key transition.

14. The method according to claim 13 , wherein the control channel is at a different wavelength than the encrypted channel.

15. The method according to claim 1 , wherein the extended key generator is based on a cipher in counter mode, and upon a disruption in synchronization a new counter is agreed upon using the control channel before resynchronizing.

16. A system for transmitting data between first and second locations with bit-level synchronization and secure resynchronization, said system comprising:

a transmitter at the first location, said transmitter including:

a key generator for extending a shared, multi-bit secret key to produce a first extended key for encrypting data to be transmitted to a receiver; and

an initialization signal generator for producing an initialization signal, wherein the encrypted data is transmitted in a multilevel format based on a binary data to be transmitted and a value of the first extended key;

the transmitter is adapted to also transmit and receive control data to and from the receiver for the transmitter and receiver synchronization, and the receiver at said second location, said receiver including a key generator for extending a shared, multi-bit secret key at a receiving location to produce a second extended key for decrypting encrypted data transmitted by the transmitter, wherein the first and second extended keys are generated substantially simultaneously with the reception of data at the receiver, wherein said transmitter transmits the initialization signal to synchronize a start of encryption with a start of decryption, and wherein

the receiver is adapted to transmit and receive control data to and from the transmitter.

17. The system according to claim 16 , further comprising using an error estimate from a forward-error correction block to determine when synchronization between the transmitter and the receiver is lost, and transmitting over the control channel an indication of loss of synchronization between the transmitter and the receiver.

18. The system according to claim 16 , wherein transmitter and the receiver employ an AlphaEta encryption and decryption protocol.

19. The system according to claim 16 , further comprising temporarily storing at least a portion of the data to be transmitted in a buffer storage during the initialization procedure.

20. The system according to claim 16 , wherein the transmitter and the receiver include a loadable key buffer, and wherein said method further comprising transmitting a fresh key to the transmitter and to the receiver over a key distribution network, and loading the fresh key into key buffers of the transmitter and the receiver, for subsequent use in generating an extended key.

21. The system according to claim 16 , further comprising using a control channel to synchronize the loading of the fresh key from the key distribution network into the key buffers.

22. The system according to claim 21 , where the control channel is at a different wavelength than the encrypted channel.