Secure classical optical communication using quantum techniques
Systems for, and methods of, detecting an attack on an optical communication channel are presented. The techniques can include sending, from a sender to a receiver, and over the optical communication channel, an optical signal, where the optical signal includes a classical optical signal representing first information and a quantum optical signal representing second information. The techniques can include detecting, by the receiver, third information from at least a portion of the quantum optical signal and sending, by the receiver to the sender, the third information. The techniques can include determining, by the sender, an indication of an attack on the optical communication channel based on at least a portion of the second information and the third information. The techniques can include triggering an alarm based on the determining.
1 . A method of detecting an attack on an optical communication channel, the method comprising:
directing a laser beam to a classical optical modulator to obtain a first modulated laser beam comprising a classical optical signal representing first information;
directing the first modulated laser beam to a quantum optical modulator to produce a second modulated laser beam comprising a quantum optical signal representing second information, wherein the quantum optical signal comprises the second information modulated in two quantum states, wherein the two quantum states comprise amplitude and phase;
sending, from a sender to a receiver, and over the optical communication channel, an optical signal, wherein the optical signal comprises the classical optical signal representing the first information and the quantum optical signal representing the second information;
detecting, by the receiver, third information from at least a portion of the quantum optical signal;
determining, an indication of an attack on the optical communication channel based on at least the third information, wherein the determining is based on determining a loss of correlation in the third information, and wherein the loss of correlation comprises an excess difference between means of distributions of the two quantum states in the third information; and
triggering an alarm based on the determining.
2 . The method of claim 1 , wherein the determining the indication of the attack further comprises determining an increase of noise.
3 . The method of claim 2 , wherein the determining the indication of the attack further comprises determining a loss of transmission, and wherein the determining the indication of the attack further comprises determining a loss of bit values.
4 . The method of claim 1 , wherein the classical optical signal is interleaved with the quantum optical signal.
5 . The method of claim 1 , wherein the attack comprises at least one of a tapping attack, a jamming attack, a correlated jamming attack, or an interrupt-resend attack.
6 . The method of claim 1 , wherein the optical communication channel comprises a distance of at least 50 km, and wherein the method has a sensitivity of less than or equal to 0.04 dB.
7 . The method of claim 1 , wherein the detecting comprises measuring using homodyne detection.
8 . The method of claim 1 , wherein the detecting comprises measuring using heterodyne detection.
9 . The method of claim 1 , further comprising differentiating a false alarm from an actual attack using a statistical technique, wherein the statistical technique comprises one of: change point detection, Bayesian change point detection, supervised learning, or cumulative sum (CUSUM).
10 . The method of claim 1 , further comprising using a Kalman filter at the receiver to predict and account for phase fluctuations in the quantum optical signal.
11 . The method of claim 1 , wherein the determining the loss of correlation in the third information comprises using a sliding window of values for which to compute the excess difference between means of distributions of the two quantum states in the third information.
12 . A system for detecting an attack on an optical communication channel, the system comprising:
a sender comprising a laser, a hardware classical optical modulator, and a hardware quantum optical modulator, wherein the sender is configured to direct a laser beam produced by the laser to the hardware classical optical modulator to obtain a first modulated laser beam comprising a classical optical signal representing first information, wherein the sender is further configured to direct the first modulated laser beam to the hardware quantum optical modulator to produce a second modulated laser beam comprising a quantum optical signal representing second information, wherein the quantum optical signal comprises the second information modulated in two quantum states, wherein the two quantum states comprise amplitude and phase, and wherein the sender is operable to send to a receiver over the optical communication channel an optical signal comprising the classical optical signal representing the first information and the quantum optical signal representing the second information;
a receiver comprising a hardware quantum optical detector and an electronic processor, and operable to detect third information from at least a portion of the quantum optical signal;
wherein the receiver is operable to determine an indication of an attack on the optical communication channel based on at least the third information, and based on determining a loss of correlation in third information, wherein the loss of correlation comprises an excess difference between means of distributions of the two quantum states in the third information and
wherein the receiver is operable to trigger an alarm that indicates the attack.
13 . The system of claim 12 , wherein the indication of the attack further comprises an increase of noise.
14 . The system of claim 13 , wherein the indication of the attack further comprises a loss of transmission, and wherein the indication of the attack further comprises a loss of bit values.
15 . The system of claim 12 , wherein the classical optical signal is interleaved with the quantum optical signal.
16 . The system of claim 12 , wherein the attack comprises at least one of a tapping attack, a jamming attack, a correlated jamming attack, or an interrupt-resend attack.
17 . The system of claim 12 , wherein the optical communication channel comprises a distance of at least 50 km, and wherein the sender is operable to determine the indication of the attack on the optical communication channel with a sensitivity of less than or equal to 0.04 dB.
18 . The system of claim 12 , wherein the receiver is operable to detect the third information from at least a portion of the quantum optical signal using homodyne detection.
19 . The system of claim 12 , wherein the receiver is operable to detect the third information from at least a portion of the quantum optical signal using heterodyne detection.
20 . The system of claim 12 , wherein the sender is operable to differentiate a false alarm from an actual attack using a statistical technique, wherein the statistical technique comprises one of: change point detection, Bayesian change point detection, supervised learning, or cumulative sum (CUSUM).
21 . The system of claim 12 , wherein the receiver further comprises a Kalman filter operable to predict and account for phase fluctuations in the quantum optical signal.
22 . The system of claim 12 , wherein the receiver is operable to determine the loss of correlation in the third information using a sliding window of values for which to compute the excess difference between means of distributions of the two quantum states in the third information.