Novel Applications of Noise in Sensing and Communications Laszlo B. Kish (1), Robert Mingesz (2), Zoltan Gingl (2), Gabor Schmera (3), Janusz Smulko (4), Chiman Kwan (5), Peter Heszler(6), Claes-Goran Granqvist (7) (1)Texas A&M University, Department of Electrical and Computer Engineering, College Station, TX, USA (2) University of Szeged, Department of Experimental Physics, Dom ter 9, Szeged, H-6720, Hungary (3) Space and Naval Warfare Systems Center San Diego, CA, USA (4) Gdansk University of Technology, Gdansk, Poland (5) Signal (6) Research (7) The Processing, Inc., Rockville, MD, USA Group of Laser Physics, University of Szeged, Hungary Ångström Laboratory, Uppsala University, Sweden Texas A&M University, Department of Electrical and Computer Engineering Noise as an information carrier: 1. Fluctuation-Enhanced Sensing 2. Johnson-Noise Informatics: - Totally secure classical communication - Zero-power communication (stealth) - Classical teleportation (totally secure networks) - Thermal noise driven computers Texas A&M University, Department of Electrical and Computer Engineering Fluctuation-Enhanced Chemical Sensing (1998-2007) • Microscopic fluctuations in a system can contain much more information about the system than the average values of the corresponding physical quantities. • Often, the measurement of these fluctuations can serve with some unique information that cannot be assessed by other means or it causes the least perturbation to the system. • Fluctuation-Enhanced Sensing (2001, John Audia, SPAWAR, US Navy): sensing of physical, chemical or biological agents where fluctuations are utilized to gain sensory information. Patents: 1. Biological: L.B. Kish, M. Cheng, R. Young, M. King, S. Bezrukov, "Sensing Phage-Triggered Ion Cascade (SEPTIC)", U.S. Patent, #: 60/630,975 (November 24, 2004). 2. L.B. Kish, G. Schmera, J. Smulko, "System and Method for Gas Recognition by Analysis of Bispectrum Function", Patent pending, Navy Case #96130 (March 2004). 3. L.B. Kish, G. Schmera"Method of Molecule Counting Using Fluctuation Enhanced Sensors", Patent pending, Navy Case #95831 (March 2004). 4. L.B. Kish, G. Schmera, "Fluctuation Enhanced Chemical Sensing by Surface Acoustic Wave Devices", US Navy patent pending, Navy Case #8412, (June 2003). 5. L.B. Kish, C.G. Granqvist and R. Vajtai, "Sampling-and-Hold Chemical Sensing by Noise Measurements for Electronic Nose Applications", Swedish patent # 990409-5. 6. L.B. Kiss, C.G. Granqvist, J. Söderlund, "Detection of chemicals based on resistance fluctuation-spectroscopy", Swedish patent, #9803019-0; Publ. # 513148. Texas A&M University, Department of Electrical and Computer Engineering Chemical sensing by Fluctuation-Enhanced Sensing. "Noise Nose" US Army Research Office small-business-research-initiative grant (joint with Signal Processing Co., Rockville, MD): Laptop Computer-Based Electronic Dog Nose by Fluctuation-Enhanced Sensing Phase-1: 7/2006-6/2007; Phase-2: 11/2007-10/2009 Texas A&M University, Department of Electrical and Computer Engineering Electronic noses Large number (6-40) of different types of sensors are needed in classical electronic noses. That implies price, reliability and aging problems. (Working temperature: 150 - 350 oC) P.E. Keller, et al, (TAC’95 conference) Texas A&M University, Department of Electrical Engineering and Computer Engineering Usual way of sensing (dR is resistance or other dc sensor signal): dR1 = A1,1 C1 + A1,2 C 2 + ... + A1,N C N . . . dR M = A M,1 C1 + A M,2 C 2 + ... + A M,N C N M≥N Texas A&M University, Department of Electrical and Computer Engineering Chemically sensitive materials produce noise. Can we use the noise spectrum to characterize the chemical environment? The first authors exploring this possibility and demonstrating it in conducting polymers were Bruno Neri and coworkers (P. Bruschi, F. Cacialli, A. Nannini and B. Neri, Sensors Actuators B 19 (1994) 421. and P. Bruschi, A. Nannini and B. Neri, Sensors Actuators B 25 (1995) 429.) Gottwald and coworkers have shown chemical sensitivity of noise in non-passivated semiconductors (P. Gottwald, Zs. Kincses and B. Szentpali, in. Unsolved Problems of Noise (UPoN’96), (World Scientific, Singapore, 1997), p. 122.) A m p l i t u d e time Texas A&M University, Department of Electrical and Computer Engineering Kish, Vajtai, Granqvist, Unsolved Problems of Noise 1999; Sensors and Actuators B, 2000) Agent-induced noise in one sensor with K characteristic frequency ranges with independent behaviour can substitute for K sensor. Single sensor electronic noise is theoretically possible dS(f1 ) = B1,1 C1 + B1,2 C 2 + ... + B1, N C N . . . dS(f K ) = BK,1 C1 + BK,2 C 2 + ... + B K, N C N K≥N Texas A&M University, Department of Electrical and Computer Engineering Fluctuation-enhanced chemical sensing. Chemical Sensor AC Preamplifier Statistical Analyzer Original Processing Texas A&M University, Department of Electrical and Computer Engineering Pattern Recognition ENHANCED CHEMICAL SENSING SYSTEM GAS SOURCES: INORGANIC ORGANIC BIOLOGICAL ODOR WARFARE A SMALL ARRAY OF TAGUCHI SENSORS GAS SENSOR ARRAY other PREAMPLIFIER AND SIGNAL CONDITIONER PATTERN GENERATOR PATTERN DATABASE PATTERN RECOGNIZER OPERATOR FEEDBACK (LEARNING PHASE ONLY) OPERATOR DISPLAY FOR ASSESSMENT Texas A&M University, Department of Electrical and Computer Engineering Lab Demo Prototype of Fluctuation-Enhanced Sensing (Fluctuation and Noise Exploitation Lab, TAMU) Preamplifier and Filters Signal Conditioning, AD Conversion Statistical Analyzer, Pattern Recognizer, Pattern Databank, Output Display, Keyboard Control Gas Sensor Chamber Sensor Driver and Signal Distributor Classical Signal Output (Single Number) Texas A&M University, Department of Electrical and Computer Engineering Is the idea new? This is, of course, already used by Nature. For example, animal noses, which produce stochastic fluctuation type signals for the animal brain. Texas A&M University, Department of Electrical and Computer Engineering Fluctuation-Enhanced Sensing is bio-mimic ! Stochastic spike train Excitation BRAIN Neuron Stochastic spike train Excitation statistical signal analysis, spatiotemporal crosscorrelation analysis, pattern recognition Neuron Stochastic spike train Excitation Neuron Texas A&M University, Department of Electrical and Computer Engineering Some experimental results on Taguchi sensors. Taguchi sensors are heated semiconductor-oxide films where the resistance of the inter-grain junctions is modulated by the adsorbed agent which act as doping. Stochastic microscopic fluctuations are generated in the sensor signal due to the diffusion of agent on the sensor's surface and in the sensor. Unfortunately, it is an obvious consequence that the elementary fluctuations are not linearly additive. Texas A&M University, Department of Electrical and Computer Engineering Nanoparticle film sensors (5nm WO3 with < 1%Palladium particles) Fluctuation-Enhanced Response in WO3 Nanoparticle Films for Gas Sensing J. Ederth, et al, Sensors and Actuators, 2005 T=350oC t 104 10000 i Sensitivity-Enhancement of 300 ! v (note, it can be even more at particular temperatures and concentrations) i 3 1000 t 10 i s 102 n100 e S The only way is to use Fluctuation-Enhanced 10 Sensing with Normalized PDS P G Gu Sensing with PDS Sensing with Resistance Sensing below 10 ppm 11 0 50 100 150 200 250 300 350 Concentration of ethanol (ppm) Texas A&M University, Department of Electrical and Computer Engineering Kish, et al, IEEE Sensors, 2005 10-24 10-26 10-28 H2S gas, SnO2 thick film sensor, 150oC 10ppm 5ppm 1ppm f Su(f)/R4 10-30 10-32 10-34 10-36 10-38 synth. air 1 synth. air 2 -40 10 synth. air 4 synth. air 3 10-42 101 102 f (Hz) Texas A&M University, Department of Electrical and Computer Engineering Texas A&M University, Department of Electrical and Computer Engineering Frozen smell. Kish, et al, ICNF 2001. The sensor stays with the fungus, even after the heating is stopped. NAP 11AS (air quality, odor sensor) f*S v(f) (arb. units) 10 -12 10 -13 10 -14 fgelgg fh11cg fh21gg fh31ad 10 -15 non-inoculated Penicillium verrucosum Penicillium roqueforti Aspergillus flavus Data taken 12 h after interruption of heating 0.1 1 10 100 1000 10000 100000 Frequency (Hz) The measurements were done in the cold state, after exposure in the warm state (heating for 1 minute), to non-inoculated and inoculated gels with Penicillium verrucosum, Penicillium roqueforti, and Aspergillus flavus fungi. The measurement was done after 12 h the heating was switched off. Texas A&M University, Department of Electrical and Computer Engineering Bispectrum. COTS sensors. More sophisticated and powerful tool. This information which is hidden when using classical power density spectra. Smulko and Kish, Sensors and Materials, 2004 Needs non-Gaussian signal (best with nanoscale sensors)! Synthetic air B( f1 , f 2 ) = F( f1 )F( f 2 )F( f1 + f 2 ) Hydrogen 380 ppm Note: all figures are generated by the same, single COTS sensor (NOx sensor) ! Ethanol fumes Ethanol 70 ppm Texas A&M University, Department of Electrical and Computer Engineering Diffusion barrier Nano-DDS Conference, Washington DC, June 2007. Spectra of the simulated situations. Molecules A, B ad C. Notations: 1A: 1 molecule A; 1B: 1 molecule C; 1A-2B: 1 molecule A and 2 molecules B; etc. The white noise at low frequencies is caused by the diffusion barriers. Texas A&M University, Department of Electrical and Computer Engineering Receiver operating characteristic (ROC) curves bispectrum: B( f1 , f 2 ) = F( f1 )F( f 2 )F( f1 + f 2 ) Texas A&M University, Department of Electrical and Computer Engineering "Johnson-noise informatics" Robert Mingesz Zoltan Gingl - Zero signal power communication (stealth) - Thermal noise driven computers (1.1 kT/bit) (c.f. Prof. Yanagida's plenary talk on Monday) - Totally secure classical communication - Classical telecloning (totally secure networks) • L.B. Kish, "Totally Secure Classical Communication Utilizing Johnson (-like) Noise and Kirchoff's Law"; • • • • • • Arxiv Preprint Server, uploaded September 15, 2005: arxiv.org/abs/physics/0509136; Physics Letters A 352 (March, 2006) 178-182. Unpublished manuscript featured in the Science magazine, by Adrian Cho, "Simple noise may stymie spies without quantum weirdness" Science 309, p. 2148 (September 30, 2005). L.B. Kish, "Protection against the man-in-the-middle-attack for the Kirchhoff-loop-Johnson(-like)-noise cipher and expansion by voltage-based security", Fluctuation and Noise Letters 6 (2006) L57-L63. L.B. Kish, R. Mingesz, "Totally secure classical networks with multipoint telecloning (teleportation) of classical bits through loops with Johnson-like noise", http://arxiv.org/abs/physics/0603041 (March 5, 2006). L.B. Kish, "Methods for using existing and currently used wire lines (power lines, phone lines, internet lines) for totally secure classical communication utilizing Kirchhoff's loop and Johnson-like noise", http://arxiv.org/abs/physics/0610014 (October 2, 2006) R. Mingesz, Zoltan Gingl, Laszlo Kish, "Realization and Experimental Demonstration of the Kirchhoff-loop-Johnson(-like)-Noise Communicator for up to 200 km range", Physics Letters A, in press (2007). Unpublished manuscript featured in the New Scientist magazine, by D. Jason Palmer, "Noise keeps spooks out of the loop" New Scientist, issue 2605, p. 32, (23 May 2007) Texas A&M University, Department of Electrical and Computer Engineering Pre-history: L.B. Kish, "Stealth communication: Zero-power classical communication, zero-quantum quantum communication and environmental-noise communication", Applied Physics Lett. 87 (December 2005), Art. No. 234109 Texas A&M University, Department of Electrical and Computer Engineering Introduction: "Stealth communication: Zero-power classical communication, zero-quantum quantum communication and environmental-noise communication", Applied Physics Lett. 87 (December 2005), Art. No. 234109 Classical and quantum communication today: the sender emits signal energy Texas A&M University, Department of Electrical and Computer Engineering Introduction: Is it possible to do communication without emitting signal energy in the information channel? (Ask around and, most probably, you will hear consistent "no" answers"...) Texas A&M University, Department of Electrical Engineering and Computer Engineering Introduction: Is it possible to do communication without emitting signal energy in the information channel? The answer is YES Texas A&M University, Department of Electrical Engineering and Computer Engineering Introduction: "Stealth communication: Zero-power classical communication, zero-quantum quantum communication and environmental-noise communication", Applied Physics Lett. 87 (December 2005), Art. No. 234109 Zero-Signal-Power Classical Communication CHANNEL SYSTEM IN THERMAL EQUILIBRIUM SENDER MODULATING A PARAMETER CONTROLLING THERMAL NOISE RECEIVER MEASURING AND ANALYZING THERMAL NOISE Texas A&M University, Department of Electrical and Computer Engineering Introduction: "Stealth communication: Zero-power classical communication, zero-quantum quantum communication and environmental-noise communication", Applied Physics Lett. 87 (December 2005), Art. No. 234109 Zero-Quantum Quantum Communication CHANNEL QUANTUM SYSTEM IN GROUND STATE SENDER MODULATING A PARAMETER CONTROLLING ZERO-POINT FLUCTUATIONS RECEIVER MEASURING AND ANALYZING ZERO-POINT FLUCTUATIONS Texas A&M University, Department of Electrical and Computer Engineering Introduction: "Stealth communication: Zero-power classical communication, zero-quantum quantum communication and environmental-noise communication", Applied Physics Lett. 87 (December 2005), Art. No. 234109 Bandwidth-based method (for wires) Classical: (kT>>h/(RC)) R C1 Quantum: (kT<<h/(RC)) 1 (T) R SENDER u1(t) To channel C2 2 u2(t) (T) Ground RECEIVER From channel NOISE ANALYZER Output Ground Texas A&M University, Department of Electrical and Computer Engineering "Stealth communication: Zero-power classical communication, zero-quantum quantum communication and environmental-noise communication", Applied Physics Lett. 87 (December 2005), Art. No. 234109 Reflection-based method (for waves) RECEIVER SENDER 3 2 Y X 1 Rw Y Rw DELAY LINE CORRELATOR RECEIVER OUTPUT Texas A&M University, Department of Electrical and Computer Engineering Introduction: Secure communication via the internet by encryption Secure key (shared by A & B) Secure key (shared by A & B) A (Alice) B (Bob) Eavesdropper (Eve) Communicator, Cipher Communicator, Cipher Encrypted information The eavesdropper (Eve) does not have the secure key thus she is unable to decrypt the information. • But how to share the secret key securely through the line when Eve is watching? • The sharing of the secret key is itself a secure communication. • It is not secure, only "computationally secure". The condition is that Eve's computing hardware and/or her algorithm is not significantly more advanced than that of Alice and Bob. Texas A&M University, Department of Electrical and Computer Engineering Introduction: What does absolute security mean? Any one of the following cases means absolute security: (quantum communication belongs to points 3 or 4) 1. The eavesdropper cannot physically access the information channel. 2. The sender and the receiver already have a shared secret key for the communication. 3. The eavesdropper has access and can do measurements on the channel but the laws of physics do not allow to extract the communicated information from the measurement data. 4. The eavesdropper can extract the communicated information however, when that happens, it disturbs the channel so that the sender and receiver discover the eavesdropping activity. Texas A&M University, Department of Electrical and Computer Engineering Introduction: Generic quantum communicator scheme (for quantum key distribution) (about $1 billion/year research funding) A (Alice) Quantum communicator B (Bob) "Dark" optical fiber Quantum communicator Single photons carry single bits Actually, one photon effectively has less than a bit information due to noise in the detection, channel and detector. Texas A&M University, Department of Electrical and Computer Engineering Introduction: Generic quantum communicator scheme (for quantum key distribution) Base of security: quantum no-cloning theorem: copies of single photons will be noisy. After making a sufficient error statistics, the eavesdropping can be discovered. Classical, public channel A (Alice) Single photons carry single bits Quantum communicator B (Bob) Quantum communicator Extra noise is introduced when the cloned photon is fed back. Eavesdropper (Eve) Texas A&M University, Department of Electrical and Computer Engineering Introduction: Generic quantum communicator scheme (for quantum key distribution) Base of security: quantum no-cloning theorem: copies of single photons will be noisy. After making a sufficient error statistics, the eavesdropping can be discovered. TO DISCOVER THE EAVESDROPPING WE NEED TO BUILD AND EVALUATE A STATISTICS! Classical, public channel A (Alice) Single photons carry single bits Quantum communicator B (Bob) Quantum communicator Extra noise is introduced when the cloned photon is fed back. Eavesdropper (Eve) Texas A&M University, Department of Electrical and Computer Engineering Introduction: Some practical problems at the conceptual level Conceptual weakness of quantum communication is the need of making a statistics to discover the eavesdropping. One-time eavesdropping on a single photon cannot be detected. This is called information leak. In practical realizations, even in the idealized case of ideal single photon source and no detector or channel noise, at least 1% of the raw bits can be extracted without a reasonable chance to discover the eavesdropping. THE EAVESDROPPER CAN HIDE IN THE NOISE AND COLLECT INFORMATION. A (Alice) B (Bob) Single photons carry single bits Quantum communicator Quantum communicator Detection noise (inherent) Channel noise (practical) Detector noise (practical) Eavesdropper (Eve) Solution (by Ch. Bennett): Privacy Amplifier (classical information software-tool) to make a short, highly secure key from a long poorly secure key. This can reduce the information leak by orders of magnitude. Texas A&M University, Department of Electrical and Computer Engineering The focus question: Is it possible to do absolutely secure communication with classical information? (When we asked it around, we had heard consistently "no" answers...) Texas A&M University, Department of Electrical and Computer Engineering The focus question: Is it possible to do totally secure communication with classical information, such as voltage and/or current in a wire? Texas A&M University, Department of Electrical and Computer Engineering The focus question: Is it possible to do totally secure communication with classical information, such as voltage and/or current in a wire? The answer is YES. Points 3 and 4 hold for the classical case, too. 3. The eavesdropper has access and can do measurements on the channel but the laws of statistical physics physics do not allow to extract the communicated information from the measurement data. 4. The eavesdropper can extract the communicated information however, when that happens, she disturbs the channel so that the communicators discover the eavesdropping activity. Texas A&M University, Department of Electrical and Computer Engineering Quantum Internet unit (telecloning to 2 Units, Fidelity 60%, at Furusawa's Lab (Tokyo, 2006) http://aph.t.u-tokyo.ac.jp/~furusawa/t_Lab_Setup.jpg Kirchhoff-Johnson Internet unit tested (pair of two communicators) Fidelity 99.98% QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Future Kirchhoff-Johnson Internet unit Texas A&M University, Department of Electrical and Computer Engineering The focus question: Pre-conclusion: two contradictory statements: 1. It was said: secure communication requires "quantum" because quantum information is very fragile and that fragility is essential for security. 2. We will see that classical information can be even more secure because classical information is extremely robust. Its security is superior to quantum security: - Zero-bit eavesdropping security; - Natural, zero-bit defense against the Man-in-the-Middle-Attack. What is the outcome of these two contradictory claims? Texas A&M University, Department of Electrical and Computer Engineering The focus question: Secure communication needs stochastics (the common factor in the quantum and classical secure communication methods). Texas A&M University, Department of Electrical and Computer Engineering Basic idea: resistor loop (Kirchhoff loop): secure key generation and sharing Possible loop resistance Rloop values: Rloop = 2*RS , 2*RL , RS + RL NOTE: THIS CIRCUIT MUST BE THE CORRECT MODEL OF THE SYSTEM OTHERWISE THE SYSTEM IS NOT SECURE! RA RB Communicator A RS Information channel (wire) RL Communicator B RS Texas A&M University, Department of Electrical and Computer Engineering RL Basic idea: resistor loop (Kirchhoff loop): secure key generation and sharing Possible loop resistance Rloop values: Rloop = 2*RS , 2*RL , RS + RL If the Eavesdropper was only passively observing and Alice and Bob could publicly measure the loop resistance without uncovering the location of the resistors then secure communication could be established in the mixed state: RB = Rloop - RA ; RA = Rloop - RB RA RB Communicator A Information channel (wire) Communicator B Eavesdropper RS RL RS Texas A&M University, Department of Electrical and Computer Engineering RL Jan Melin's report Texas A&M University, Department of Electrical and Computer Engineering Secret Key Generation and Exchange: Simplest Example for Totally Secure Classical Communication The idealized system defined by this circuit diagram is totally secure, conceptually/theoretically. The foundation of this security is: The Second Law of Thermodynamics (out of Kirchhoff's laws). UCh(t), ICh(t) A R1 U1A(t) Su1A(f) R0 U0A(t) Su0A(f) B R0 U0B(t) Su1B(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1B(t) Su1B(f) The loop resistance can be evaluated in two different ways Johnson-Nyquist formulas for this Kirchhoff loop: Su, R|| ( f ) = 4kT R A RB R A + RB Si, R || ( f ) = (a) R A RB R A + RB UCh(t) SCh(f) 4kT R A + RB (b) R A + RB UA(t)+UB(t) SuSA(f)+SuRB(f) ICh(t) SiCh(f) Texas A&M University, Department of Electrical and Computer Engineering SECURE KEY GENERATION AND EXCHANGE BY VOLTAGE MEASUREMENTS Su,ch SECURE BIT IS GENERATED/SHARED time A B UCh(t), ICh(t) Su,ch Si,ch R1 U1A(t) Su1A(f) R0 U0SA(t) Su0A(f) R0 U0B(t) Su1B(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1B(t) Su1B(f) Eavesdropper's Passively Observed/Extracted Information: Resistances but not their locations R1, 2 = 4kTSu,ch ± ( 4kTSu,ch 2 ) 3 - 4Su,ch Si,ch 2Su,ch Si,ch A B UCh(t), ICh(t) Su,ch Si,ch R1 U1A(t) Su1A(f) R0 U0A(t) Su0A(f) R0 U0B(t) Su1B(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1B(t) Su1B(f) Eavesdropper's Passively Observed/Extracted Information: Resistance values but not their locations. Gaussian processes allow distribution functions up to the second order only. But the net power flow is zero because the Johnson-Nyquist formula of thermal noise is based on the Fluctuation-Dissipation Theorem which satisfies the Second Law of Thermodynamics. Therefore the total security is related to the impossibility of constructing a perpetual motion machine. U ch I ch = 0 A B UCh(t), ICh(t) Su,ch Si,ch R1 U1A(t) Su1A(f) R0 U0A(t) Su0A(f) R0 U0B(t) Su1B(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1B(t) Su1B(f) Hacking into the Communicator: Active Eavesdropping DI can be small stochastic (crosscorrelation between DU and DI ) or a large, short current pulse Alice SENDER DI ES (t) Bob RECEIVER DI ER (t) DU E ,Ch (t) R1 U1S(t) Su1S(f) R0 U0S(t) Su0S(f) DI E (t) R0 U0R(t) Su1R(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1R(t) Su1R(f) Uncovering the eavesdropper by: Broadcasting the instantaneous current data and comparing them THE EAVESDROPPER IS DISCOVERED WHILE EXTRACTING A SINGLE BIT OF INFORMATION. The stochastic current method can extract zero bit, the large current pulse method can extract one bit. BETTER THAN KNOWN QUANTUM COMMUNICATION SCHEMES BECAUSE NO STATISTICS IS NEEDED. Alice SENDER A DI ES (t) DI ER (t) A Bob RECEIVER DU E ,Ch (t) R1 U1S(t) Su1S(f) R0 U0S(t) Su0S(f) DI E (t) R0 U0R(t) Su1R(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1R(t) Su1R(f) The attack "below the belt": Man-In-The-Middle (MITM) attack The original current-comparison naturally defends against it Alice SENDER I S,Ch (t) I R,Ch (t) R0 R1 R0 U1,S(t) U0,S(t) Su1,S(f) Su0,S(f) R1 R0 Bob RECEIVER R1 R0 R1 U0,E(t) U1,E(t) U0,E(t) U1,E(t) U0,R(t) U1,R(t) Su0,E(f) Su1,E(f) Su0,E(f) Su1,E(f) Su1,R(f) Su1,R(f) Texas A&M University, Department of Electrical and Computer Engineering Let us suppose 7 bits resolution of the measurement (a pessimistic value), then P0 = 1 / 128 , which is less than 1% chance of staying hidden. On the other hand, P0 is the probability that the eavesdropper can stay hidden during the correlation time t of the noise, where t is roughly the inverse of the noise bandwidth. Because the KLJN cipher works with statistics made on noise, the actual clock period T is N >> 1 times longer than the correlation time of the noise used [1]. Thus, during the clock period, the probability of staying hidden is: Pclock = P0N Supposing a practical T = 10t (see [1]) the probability at the other example P < 10 - 20 . This is the estimated probability that, in the given system the eavesdropper can extract a single bit without getting discovered. The probability that she can stay hidden while extracting 2 bits is P < 10 - 40 , for 3 bits it is P < 10 - 60 , etc. In conclusion, we can safely say that the eavesdropper is discovered immediately before she can extract a single bit of information. At 7 bit current comparison, the probability of staying hidden for a single clock period is less than 10-20 Texas A&M University, Department of Electrical and Computer Engineering Suppose the eavesdropper synchronizes the current values with twin current generators during the MITM attack. She can extract at most one bit while she is discovered. She will be discovered because the high-resistance end will see a large voltage and interpret the situation as it is a non-secure-bit communication case. The other end will interpret it as a secure bit communication. This contradiction uncovers the eavesdropper. However: she can extract zero bit if the voltage values are also compared at the two ends. Alice SENDER Bob RECEIVER V R1 U1,S(t) Su1,S(f) R0 U0,S(t) Su0,S(f) V R0 U0,R(t) Su1,R(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1,R(t) Su1,R(f) Suppose, the eavesdropper synchronize the voltage values with two twin voltage generators during the MITM attack? Then she can extract zero bits because the current values are compared at the two ends, already in the original scheme. Alice SENDER R1 U1,S(t) Su1,S(f) Bob RECEIVER R0 U0,S(t) Su0,S(f) R0 U0,R(t) Su1,R(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1,R(t) Su1,R(f) Measuring and comparing the instantaneous voltage and current values provides total, zero-bit security, against invasive attacks CLASSICAL INFORMATION IS ROBUST AND IT ALLOWS CONTINUOUS MONITORING ! Public channel for broadcasting/comparing the instantaneous values of local current (A) and voltage (V) data Alice SENDER DI ES (t) A V R1 U1S(t) Su1S(f) R0 U0S(t) Su0S(f) DI ER (t) DU E ,Ch (t) DI E (t) A Bob RECEIVER V R0 U0R(t) Su1R(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1R(t) Su1R(f) What does absolute security mean? Any one of the following cases means absolute security: (quantum communication belongs to points 3 or 4) 1. The eavesdropper cannot physically access the information channel. 2. The sender and the receiver have a shared secret key for the communication. 3. The eavesdropper has access and can do measurements on the channel but the laws of physics do not allow to extract the communicated information from the measurement data. 4. The eavesdropper can extract the communicated information however, when that happens, it disturbs the channel so that the sender and receiver discover the eavesdropping activity. Texas A&M University, Department of Electrical and Computer Engineering Conclusion about the idealized chipher, as it is defined by its circuit diagram 1. A dogma was killed. It is possible to do secure communication via a classical channel. 2. Secure communication through a wire. 3. Natural protection against the man-in-the-middle-attack. 4. The eavesdropper is discovered latest after extracting a single bit. 5. Extremely robust: vibration, dust, thermal gradient, ageing resistant. The noise voltage can be in the order of tens of volts, which makes screening unnecessary. 6. Very cheap compared to quantum informatics. No single mode lasers, cooled detectors, thermal and vibration protection are needed and virtually no maintenance costs. 7. Stealth communication, if necessary. Texas A&M University, Department of Electrical and Computer Engineering Conceptual and practical aspects: important questions and comparisons • During efficient breaking in, how many bits can the eavesdropper extract without uncovering the eavesdropping in an idealized scheme? - RSA: infinite number of bits - Quantum: usually a few thousand bits - Kirchhoff-Johnson: zero bit. Because no statistics making is needed for eavesdropper detection. Impossible with quantum informatics. • Security at practical situations. While the theoretical concept offers total security, total security of practical physical secure communicators is like approaching zero or infinity in physics. Never exists in reality, for example, in quantum communication: no ideal single photon source no noise-free channel no noise-free detector, etc. Texas A&M University, Department of Electrical and Computer Engineering Practical limits For total security, the loop must be exactly the same as defined by its circuit diagram. Any deviation may give information to the eavesdropper. The situation is similar to the case of quantum communication: The more we approach the ideal conditions, the more secure the system is. Therefore the security of the system can be designed to the required level depending on resources. 1. Wave situation should be avoided. fmax L << c Moreover, the clock frequency should be low-enough to make a sufficient statistics: fc << fmax F or a pra ct ic a l e stim a ti on, l e t u s s uppose tha t c = 2 * 10 8 m e te r/s , f max L = 0 .1 * c , and f c = 0 .1 * f max . T hen t he e f fe c ti ve bandw id th - d is tanc e produ ct f c L = 2 * 10 6 m e te r Hz . T hi s is sl igh tl y (f ac to r of 2-3 ) b et te r than p r e s en t qu a ntu m co mm un ica to r a rr ange m en ts [ 8] I. Marcikic, H. de Riedmatten, W. Tittel, H. Zbinden, and N. Gisin, Long distance teleportation of qubits at telecom wavelength, Nature 421, 509 (2003 ). MULTI WIRE+CHIP! 2. Inaccuracies: Wire resistance should be much less than any of the bit resistances. The bit resistances and noise generators should be as identical at Alice and Bob as possible. 3. Wire capacitance and inductance should not effect the loop impedance. This is another constraint on the frequency bandwidth (but should be easy to handle it with artificial noise generators). 4. Transients. Caused much concern and generated fundamental questions among colleagues but easiest to deal with this problem in the practice (especially for non-stealth communication). Texas A&M University, Department of Electrical and Computer Engineering Assuming waves, serial resistance (Bergou-Scheuer-Yariv), different noise temperatures (Hao), etc, are deviations from basic assumptions and imply different circuitries which are not totally secure. Such assumptions are allowed at the practical considerations but they have nothing to do with the security at the conceptual level. A B UCh(t), ICh(t) Su,ch Si,ch R1 U1A(t) Su1A(f) R0 U0SA(t) Su0A(f) R0 U0B(t) Su1B(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1B(t) Su1B(f) Assuming waves, serial resistance (Bergou-Scheuer-Yariv), different noise temperatures (Hao), etc, are deviations from basic assumptions and imply different circuitries which are not totally secure. Such assumptions are allowed at the practical considerations but they have nothing to do with the security at the conceptual level. distributed RLC network A B UCh(t), ICh(t) Su,ch Si,ch R1 U1A(t) Su1A(f) R0 U0SA(t) Su0A(f) R0 U0B(t) Su1B(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1B(t) Su1B(f) Practical limits For total security, the loop must be exactly the same as defined by its circuit diagram. Any deviation may give information to the eavesdropper. The situation is similar to the case of quantum communication: The more we approach the ideal conditions, the more secure the system is. Therefore the security of the system can be designed to the required level depending on resources. 1. Wave situation should be avoided. fmax L << c Moreover, the clock frequency should be low-enough to make a sufficient statistics: fc << fmax F or a pra ct ic a l e stim a ti on, l e t u s s uppose tha t c = 2 * 10 8 m e te r/s , f max L = 0 .1 * c , and f c = 0 .1 * f max . T hen t he e f fe c ti ve bandw id th - d is tanc e produ ct f c L = 2 * 10 6 m e te r Hz . T hi s is sl igh tl y (f ac to r of 2-3 ) b et te r than p r e s en t qu a ntu m co mm un ica to r a rr ange m en ts [ 8] I. Marcikic, H. de Riedmatten, W. Tittel, H. Zbinden, and N. Gisin, Long distance teleportation of qubits at telecom wavelength, Nature 421, 509 (2003 ). MULTI WIRE+CHIP! 2. Inaccuracies: Wire resistance should be much less than any of the bit resistances. The bit resistances and noise generators should be as identical at Alice and Bob as possible. 3. Wire capacitance and inductance should not effect the loop impedance. This is another constraint on the frequency bandwidth (but should be easy to handle it with artificial noise generators). 4. Transients. Caused much concern and generated fundamental questions among colleagues but easiest to deal with this problem in the practice (especially for non-stealth communication). Texas A&M University, Department of Electrical and Computer Engineering Example for generic practical solution Alice Bob Texas A&M University, Department of Electrical and Computer Engineering Inaccuracies. How large is the impact of 1% inaccuracy? Response to Scheuer-Yariv's only meaningful point. They indicate 1% voltage drop on the wire at certain practical conditions. They say that is enough for the eavesdropper to decode the signal. Here is the proof that their claim is not true. Model study of distribution functions [7]. (a): Amplitude distribution functions sampled by the sender and receiver. (b): Amplitude distribution functions sampled by the eavesdropper at the two ends of the wire. Though we accept the 1% drop of the MS voltage as a realistic practical goal [7] we disagree with Sch-Y's claim that the eavesdropper can easily detect this 1% drop. Shannon's channel coding theorem: C = fc [1+ p log2 p + (1- p) log 2 (1- p)] With the very same voltage drop, we have ca rried out a model study [7] of the distribution functions of the voltages, currents and the drop of the MS voltage for R1 / R0 = 10, with a linear full-wave de tector [14] and clock period t c = 3/ fmax r esu lts in rel at iv e st andard dev ia ti on 0.2 of the vo lt age and cur r en t sta tis tic s [ 14 ]. Th e r esu lts a r e su mm a ri zed in Fi gure 2. No te , on ly th e r e la ti ve pos iti ons and the sh a pe o f th e cu rves have m ean ing , no t th e ac tu a l x a nd y va lues . D ur ing th e c lock pe ri od, due to Eq . ( 2) , the tim e is enough on ly fo r a fe w st a ti sti ca ll y ind e penden t s a m p li ng o f the s e d istri bu ti on f unc ti ons . T h is sa m p li ng is enough f or t he s ende r a nd the re ce ive r , se e Fi gur e 2 (a ) , t o d e c ide b e tw een th e two func ti on s w it h 0.3 % e rr or r a te [ 7 ] . Howeve r the eav e sd r oppe r , who m ea s u r es t he vo lt age d r op, has t o de c id e be tw e en the t wo sit ua ti ons by sa m p li ng the f (x ) a nd g (x) den s ity fun ct ion s g iv e n in Fi g . 2 (b ) a nd tha t m us t b e done w it h the sam e sm a ll nu m be r o f ind e penden t s a m p les . T he cha r ac ter isti cs w id th (s ta nda r d dev ia ti on ) o f the s e curv e s (20 % o f th e pe a k's x coo r d ina te ) is 20 tim e s g rea te r t han the d if fe r enc e o f the l oca ti ons o f the x coo rd ina te s o f the peak s (1 % ). T he e ave s droppe r 's ta s k se e m s t o be hope les s by the naked eye ho w eve r , by u s ing p r oper sta tisti ca l too ls , she can still e x tra c t so me in f or m a ti on . A deepe r a na lys is ba s ed on Shannon 's channe l cod ing theo r em [7 ] con cl udes t ha t in t hi s c ase the uppe r li m it o f i n forma ti on le ak is 0 .7% o f the tr ans mitt ed b its . Th is is c lo s e to bu t le s s th a n the i nfo rm a ti on le a k o f quan tu m co mm un ica to r s w it hou t p ri vacy a m p lifi e r s of tw a re ( see above ). T hus S c h-Y' s 1 % d r op of the M S vo lt ag e y ie lds a l owe r in for m a ti on l eak th a n tha t of quan tu m co mm un ica to r s. Su,ch Texas A&M University, Department of Electrical and Computer Engineering time The realized communicator pair. Statistics at Alice's side during 74497 clock cycles. At a BSchY attack, the eavesdropper will have only a single clock cycle to distinguish between LH and HL. The wire resistance is about 2% of the loop resistance during the LH or HL states: RL=2 kOhm, RH=11kOhm, Rw=200 Ohm. (a) (b) (c) Texas A&M University, Department of Electrical and Computer Engineering Statistics at Alice's side during a BSchY attack, single clock cycle. (a) The wire resistance is about 2% of the loop resistance during the LH or HL states: RL=2 kOhm, RH=11kOHm, Rw=200 Ohm. The poor statistics seen in figures (a) and (b) are enough for Alice and Bob to identify secure bit alignment with 0.02% error rate (99.88% fidelity). However when Eve tries to identify the bits from the two histogram recorded at the two ends of the line (see figure (c)) she must work with these distributions which are very stochastic, almost identical and totally overlapping with a 1% or less shift of their centers [7] which results in less than 0.19% eavesdropped bit / transmitted secure bit. Three independent records of LH and HL at Alice's side (c) Single record of each states at Alice's side (b) Texas A&M University, Department of Electrical and Computer Engineering R. Mingesz, Z. Gingl, L.B. Kish, Realization and Experimental Demonstration of the Kirchhoff-loop-Johnson(-like)Noise Communicator for up to 2000 km range; www.arxiv.org/abs/physics/0612153 Texas A&M University, Department of Electrical and Computer Engineering R. Mingesz, Z. Gingl, L.B. Kish, Realization and Experimental Demonstration of the Kirchhoff-loop-Johnson(-like)Noise Communicator for up to 2000 km range; www.arxiv.org/abs/physics/0612153 DSP Unit Analog Unit KLJN Line Analog Unit DSP Unit Computer The computer control parts of the communicator pair have been realized by ADSP-2181 type Digital Signal Processors (DSP) (Analog Devices). Robert Mingesz Zoltan Gingl The communication line current and voltage data were measured by (Analog Devices) AD-7865 type AD converters with 14 bits resolution from which 12 bits were used. The DA converters were (Analog Devices) AD-7836 type with 14 bits resolution. The Johnson-like noise was digitally generated in the Gaussian Noise Generator unit where digital and an alog filters truncated the bandwidth in order to satisfy the KLJN preconditions of removing any s purious frequency components. The major bandwidth setting is provided by an 8 -th order Butterworth filter with sampling frequency of 50 kHz. The remaining small digital quantization noise components are removed by analog filters. The experiments were carried out on a model-line, with assumed cable velocity of light of 2*10 8 m/s, with ranges up to 2000 km, which is far beyond the range of direct quantum channels, or of any other direct communication method via optical fibers. The device has bit rates of 0.1, 1, 10, and 100 b it/second for ranges 2000, 200, 20 and 2 k m, respectively. The wire diameters of the line model are selected so that they resulted in about 200 Ohm internal resistance for all the different ranges. The corresponding copper wire diameters are reasonable practical values for the different ranges are 21 mm (2000 km), 7 mm (200 km), 2.3 mm (20 km) and 0.7 mm (2 km). Inductance effects are negligible with the selected resistance values, R0 and R1 , at the given ranges and the corresponding bandwidths. If the wire is a free hanging one with a few meters separation from earth, such as power lines, parasitic capacitances are not a problem up to 10% of the nominal range. For longer ranges than that, either coaxial cables driven by the capacitor killer are needed or the speed/bandwidth must be decreased accordingly. Texas A&M University, Department of Electrical and Computer Engineering R. Mingesz, Z. Gingl, L.B. Kish, Realization and Experimental Demonstration of the Kirchhoff-loop-Johnson(-like)Noise Communicator for up to 2000 km range; www.arxiv.org/abs/physics/0612153 The noise bandwidth is selected so that the highest possible Fourier component in the line is at frequency 10 times lower than the lowest frequency standing-wave mode in the line. That condition results in noise bandwidths 5, 50, 500 and 5000 Hz fo r ranges 2000, 200, 20 and 2 km, respectively. Transient wave effects at the end of clock period are avoided in the Gaussian Noise Generator unit by driving the envelope of the time functions of noise voltage and current to zero before the switching using a linear ramp amplitude modulation (via 8% of the clock duration); and the reverse process is done at the beginning of the next clock cycle after the switching of resistors. Moreover a short pause (8 % of the clock time) with no data collection, except for security check, after the initial linear ramp at the beginning of stationary noise, is applied in order to avoid possible other types of transient effects of stochastic nature (though we have not seen any transients). All these are done before the filtering process to avoid any spurious frequency components due to the linear ramp. Because the security protection based on current and voltage comparison was effective up to 50 kHz bandwidth, 1 nF capacitors at the two ends of the line were satisfactory line filters. Furthermore, these capacitors would have removed possible switching spikes originating from capacitive coupling in the analog switches due to possibly unbalanced parasitic capacitors; therefore there were no detectable switching transients in the line. The 11 kOhm resistor is composed by conn ecting a 9 kOhm serial resistor to the 2 kOhm resistor. The 2 kOhm resistors are two serial 1kOhm resistors with a 1 nF capacitor shunting their joint point to the ground to remove possible digital quantization noise. The 1 kOhm resistor at the generator dive end was also used as a probe to measure the current in the line. The value of K is selected so that the noise voltage of the greater resistor is 1 Volt for all noise bandwidths. This resulted in Su ( f ) values of the greater resistor 0.2, 0.02, 0.002, 0.0002 V 2 /Hz for ranges 2000, 200, 20 and 2 k m, respectively. Note: cable capacitance provides a further filtering but we cannot relay on that alone because of eavesdropping possibility. Texas A&M University, Department of Electrical and Computer Engineering R. Mingesz, Z. Gingl, L.B. Kish, Realization and Experimental Demonstration of the Kirchhoff-loop-Johnson(-like)Noise Communicator for up to 2000 km range; www.arxiv.org/abs/physics/0612153 Eavesdropping tests. Sample size: 74,497 clock cycle Ceav = 1+ p log 2 p + (1 - p) log 2 (1- p) C trans MEASURED NUMBER, OR RATIO, OF TYPE OF BREAKING EAVESDROPPABLE BITS WITHOUT SETTING ON THE CURRENT-VOLTAGE ALARM (TESTED THROUGH 74497 BITS) REMARKS 0.19% 0.00000019% at 1 0 times thicker wire (theoretical extrapolation). Arbitrarily can be enhanced by privacy amplification [12,13]; the price is slowing down. Hao (iii) [ 8] attack in the present KLJN system Zero bit Below the statistical inaccuracy. Considering the 12 bit effective resolution of noise generation accuracy, it is theoretically: < 0.000000006% Kish (iv) [ 9] attack utilizing resistor inaccuracies in the present KLJN system Zero bit Current pulse injection (Kish) [1] in the present KLJN system Zero bit BSchY (i) [2,6] attack in the present KLJN system Below statistical inaccuracy. Theoretically, when pessimistically supposing 1% resistance inaccuracy, it is: < 0.01% One bit can be extracted while the alarm goes on thus the bit cannot be used. Texas A&M University, Department of Electrical and Computer Engineering Quantum telecloning to 2 Units, Fidelity 60%, at Furusawa's Lab (Tokyo) http://aph.t.u-tokyo.ac.jp/~furusawa/t_Lab_Setup.jpg Kirchhoff-Johnson network element tested Fidelity 99.8% QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Future Kirchhoff-Johnson network element Texas A&M University, Department of Electrical and Computer Engineering How about using existing wires to build a network? • Quantum communicators need "dark optical fibers", which are separate well isolated fibers, because the single photon concerns. • Can we use existing and currently used wires, such as power lines, phone lines, internet wire lines? • The answer is yes. http://arxiv.org/abs/physics/0610014 Texas A&M University, Department of Electrical and Computer Engineering Line Filter Box Line 1 BE BP 3 BP BE BE BE Line BP 2 RL RH RN RH RL External Line In External Line Out 1 3 Line Filter Box 2 Local line (e.g. to hou sehold line input) The line filter box (see Figure 1) should be installed at each intersection of the line to separate the non-KLJN communicator loads from the KLJN frequency band. Communicator A Communicator B Example for how to use KLJN frequency Band Excluder (BE) and Band Pass (BP) filters to preserve a single Kirchhoff loop in the KLJN frequency band between two KLJN communicators with one intersection between them. Thick (blue) lines: original line current; thin (red) line: KLJN current; double (green) lines: both types of currents. Texas A&M University, Department of Electrical and Computer Engineering Power Station A Power Station B Communicator A Communicator B (KLJN) (KLJN) Communication via idealized 3-phase power lines with symmetric loads of the 3-phase transformers at Power Stations A and B, respectively. Texas A&M University, Department of Electrical and Computer Engineering Power Station A Power Station B BP Communicator A (KLJN) BP BE BE Communicator B (KLJN) Co mm un ica ti on v ia p rac ti ca l 3 -phase powe r li ne s. Texas A&M University, Department of Electrical and Computer Engineering Telecloning (teleportation) of bits via the network. L1 R1 L2 R2 L3 R3 Coordinator-server (CS) and regular network Note: the Coordinator-server is also connected by a KLJN wire to one of the units, say to Unit 1. •The Units run their KLJN ciphers until a secure bit exchange is reached. •Then each Unit reports to the CS the logic relation, G [ = +1 (same bit) or -1 (opposite bit)], between their own left port and the bit at the left port of the right hand neighbor. •If the Nth Unit wants to clone the bit at the left hand side of Unit 1, then he sends a request to the CS. N- 1 •The CS calculates F = P Gk and send F to Unit N. Then Unit N multiplies his own left bit 1 (+/-1) with F and gets the teleclone of the left bit of Unit 1. This cloned bit exists only at Unit 1 and Unit N. It does not exist at the other Units at the CS: teleportation type transfer. Texas A&M University, Department of Electrical and Computer Engineering Multi-telecloning and secure key exchange over the whole network L1 R1 L2 R2 L3 R3 Coordinator-server (CS) and regular network Note: the Coordinator-server is also connected by a KLJN wire to one of the units, say to Unit 1. Suppose, the regular network is fast enough. •The CS calculates and sends all the relevant Fjk functions to all Units. •Then the Units calculate the bit status of all the other units. •Note, the whole process needs only a few clock period until most units have a secure bit exchange. In 3 clock periods, about 85% (5/6) of the units has secure bit. •We have generated and exchanged a 0.85*N bit long secure key over the whole network in 3 clock periods of the KLJN cipher ! Texas A&M University, Department of Electrical and Computer Engineering Initialization for unconditional security (Mingesz attack) Robert Mingesz has pointed out some important vulnerabilities. If the eavesdropper accesses the communication in the regular network and learns all the F functions belonging to the telecloning to one Unit, she will know either the network key or its inverse. L1 R1 L2 R2 L3 R3 Coordinator-server (CS) and regular network Therefore, the regular network must be made totally secure which requires a specific installation process, where first an at least N-bit long secret key is generated at Unit one. At the same time, each inter-Unit-connection and Unit-CS-connections also generate independent Nbit long secure keys. Then, they use the regular network and the inter-connection secure keys as a One-Time-Pad to transfer/share from Unit-to-Unit the N-bit long key generated by the first Unit. The Coordinator server should also posses a Unit. This initialization process takes time (about 7 minutes for the NY example) however, at the end the whole network shares an N-bit long secure key. And the system can run in the way described earlier so that the communication via this regular network during the first network key distribution uses this secret key. Later, the regular network is using the network key generated/shared at the previous clock cycle. Texas A&M University, Department of Electrical and Computer Engineering Conclusion: 1. Johnson (-like) noise makes absolutely secure classical communication possible. 2. The foundation of the security are Statistical Physics (the Second Law of Thermodynamics), and the robustness of classical information. 3. Due to the robustness of classical information, the communicator is conceptually more secure than quantum communicators because zero-bit security is theoretically possible. 4. Concerning practical aspects, it seems, the Johnson (-like) noise based communicator is superior to quantum communicators in all known practical aspects, except the inability to communicate without wire. 5. It is computer chip/card and network ready device. Texas A&M University, Department of Electrical and Computer Engineering End of talk Texas A&M University, Department of Electrical and Computer Engineering Texas A&M University, Department of Electrical and Computer Engineering Texas A&M University, Department of Electrical and Computer Engineering Superior to quantum communication regarding: security; speed; price; robustness against vibration, shock, dust, ageing; network readiness; low power consumption. Disadvantage: needs a wire. Note: this comparison table is for the usual case when quantum communication is trying to transfer the quantum state securely. If this luxury aim is abandoned (see above) then its performance will significantly improve at the network key distribution and telecloning aspects. 100% fidelity is theoretically possible. Quantum Comm. KLJN Comm. Physics behind the security Quantum (Fragile information bit) Classical statistical (Robust information bit) Max. number of eavesdropped bits before 99% probability of eavesdropper detection Few thousand 0-4 Vulnerability against the man-in-the-middle attack Usually yes No Information leak below the eavesdropper detection radar (eavesdropper hiding in noise) >1% 0.01% or less is easily reachable Ultimate speed-cut-off versus range Exponential cut-off 1/range cut-off Network key distribution No. Only point-to-point Yes. Whole-network key distribution within two clock periods Telecloning Yes, with fidelity < 71% Yes, with 100% fidelity Network telecloning in one step. Number of units N N Æ• N- 1 (N 2 - N) / 2 N ª 30 Vibration resistant No Yes Shock resistance Poor Excellent Dust resistant No Yes Microelectronic integrated parallel multi-line (>100) driver chip No Yes Low-power consumption No Yes Texas A&M University, Department of Electrical and Computer Engineering December 2005, over 500 websites with various blogs. Many knows what is a resistor and a Kirchhoff-loop and feels relevant expertise. Less knows what noise is. More reasonable comments tried to break the system with arguments relevant for the practical system. No one could challenge the security of the idealized system. http://www.impactlab.com The German "Bundesamt für Sicherheit in der Informationstechnik (BSI)" (Federal Office for Information Security) that sent me multiple emails containing attempts to break the cipher. All these efforts have been without success because of relevant the statistical physical properties of thermal(-like) noises, which is a great physical encryption mechanism. Texas A&M University, Department of Electrical and Computer Engineering Many emails in last December! Some significant ones. >Bruce, please save my time and send me only serious comments. Or ask somebody else to check before >because my time/energy is limited. Laszlo, the author of this note is *very* serious. He was a top-notch cryptographic mathematician and number theorist, and the former head of the relevant department at Bell Labs. And of course, the Shamir he cc'd is the "S" of RSA. http://www.schneier.com Texas A&M University, Department of Electrical and Computer Engineering www.schneier.com/blog/archives/2006/02/more_on_kishs_c.html Texas A&M University, Department of Electrical and Computer Engineering On the Impossibility of Keeping Out Eavesdroppers Using Only Classical Physics by Terry Bollinger http://terrybollinger.com/qencrypt/BollingerCritiqueOfKishPaper-2006-01-31.pdf "The nice thing about this visualization is that it provides a fairly vivid way of understanding why it is so hard to be sneaky in quantum communications. The problem is this: When someone attempts to sneak in an observation on an entangled set of particles in the here-and-now, the quantum result look just as if a record of that transgression was captured, sent back in time to the original generation of the entangled particles, and then rebroadcast for everyone in the future to see. It is a bit like breaking into a store today, only to find out that last week the store had already shipped out a video of you doing it to every police station in the area." Response to Bollinger's "On the Impossibility of Keeping Out Eavesdroppers Using Only Classical Physics" and to Some Other Comments at Bruce Schneier's Blog Sites by Laszlo B. Kish www.ece.tamu.edu/~noise/research_files/Response_Bollinger.pdf Apple - Orange: Quantum Physics - Classical Statistical Physics The passively observing eavesdropper has zero info. However, if she is invasive and breaks the lock, the police arrives during that process. Based on the Second Law of Thermodynamics: to extract info from the idealized cipher by a passive observer is a similar kind of job like building a perpetual motion machine. Texas A&M University, Department of Electrical and Computer Engineering It is with some distress that I have, as of yesterday, switched from being someone about to post a blistering critique of Kish's proposal to someone who had a not-entirely-pleasant "aha!" moment about it. It is now my public statement, speaking only for myself, that as best I can tell Kish's proposal works at least as well in the engineering limit as quantum proposals to accomplish very similar goals. . . . And my final comment is: wow. -speaking only for myself-Posted by: Terry Bollinger at March 9, 2006 10:46 AM www.schneier.com/blog/archives/2006/02/more_on_kishs_c.html Texas A&M University, Department of Electrical and Computer Engineering Quantum realization (!!!) Telecloning and secure distribution of classical bits via quantum communicator network without telecloning the quantum states quantum entangled bit exchange units L1 R1 L2 R2 L3 R3 Coordinator-server (CS) and regular network If quantum information networks will be practically applied (whenever wire communication is impossible), then this should be the way to go. We do not need to transfer the quantum states! That would be an unnecessary luxury. We need only to transfer the information bit securely. Texas A&M University, Department of Electrical and Computer Engineering The enhancements: each clock period can be used but that will need double wires and special complementary channels. Worthwhile? (Probably not). It will need a more complex initialization against the Mingesz attacks (see in the paper). A B A B Known port distribution: unsecure U A1 B1 Secure port distribution: secure A1 B1 A2 B2 U A 2 B2 Example: the A1 and B1 ports are run randomly/independently until the first secure bit: Situation of secure bits Low (-1) at B1 A1 A1 B1 Resulting port control A1 = A2 B1 = B2 - B2 A1 = A2 - A2 B1 = B2 Texas A&M University, Department of Electrical and Computer Engineering A POSSIBLE SOLUTION OF KLJN NETWORKS. - The simplest connection which is almost as good as the best one: The single-wire network of electrically isolated Kirchhoff loops - Telecloning (teleportation) of bits via the network. - Multi-telecloning and secure key exchange over the whole network - Quantum realization (!!!): telecloning of classical bits via quantum networks without telecloning the quantum state - Initialization for maximal security (Mingesz attacks) - Enhanced KLJN communicator making use of 100% of clock periods - Some of the many questions and about perspectives Texas A&M University, Department of Electrical and Computer Engineering The simplest connection. The single-wire network of electrically isolated Kirchhoff-loop-Johnson-like-noise (KLJN) ciphers. Eeach Unit has two communicators (left and right). L1 R1 L2 R2 L3 R3 Coordinator-server (CS) and regular network Note: the Coordinator-server is also connected by a KLJN wire to one of the units, say to Unit 1. If the bit is sent through the line from the left to the right so that the Mth unit measures the secure bit at the left port and Unit (M-1) tells Unit M through the regular network that the measured bit is correct or opposite, the communication through N units will need about 2*N clock periods, which is very slow because single-wire KLJN units for short distance are similarly slow as quantum communicators. So, how can we use this network for high-speed key generation? Telecloning of the local secure bits to all the units. Note: the attached regular network can be million times faster! Texas A&M University, Department of Electrical and Computer Engineering SECURE KEY GENERATION AND EXCHANGE Su,ch SECURE BIT IS GENERATED/SHARED time A B UCh(t), ICh(t) Su,ch Si,ch R1 U1A(t) Su1A(f) R0 U0SA(t) Su0A(f) R0 U0B(t) Su1B(f) Texas A&M University, Department of Electrical and Computer Engineering R1 U1B(t) Su1B(f) Examples: 1% of NY's population (200,000) people are connected by a KLJN computer card and wire connections of less than 1km between nearest neighbors. Then the clock period is less than 1 msec. If the regular network is fast enough, a secure key generation and whole-network distribution can be done with 60Mbit/sec speed. 1% of Bryan-College Station population (2000 people), otherwise the same conditions. The theoretical speed is 600kbit/sec. Compare this with your 128 bit key secure internet connection. Texas A&M University, Department of Electrical and Computer Engineering Remarks: small number of connections needed (nearest neighbor) It is i mportant to note that the network described in Figure 7 is very different from the basically point-topoint key distribution methods used by quantum communication and software solutions. Even though, the possibility of telecloning of quantum states to multiple receivers has been pointed out by van Loock and Braunstein [8] the fidelity is poor (<71%) and to reach an acceptable fidelity (>50%) the number of Units has to be limited to 30. Moreover, each Unit has to be connected to all the other Units by a separate communicator and separate lines, which means N (N - 1) communicator devices and (N 2 - N) / 2 l ines indicating that the method is essentially a point-to-point communication type. For the New York example mentioned above, such a quantum telecloning solution requires about 200 thousand communicator devices at each Unit and that requires almost 40 billion communicator devices and nearly 40 billion optical cables. Moreover, these 40 billion connections are both short-distance and long-distance ones because we ha ve to directly connect the farthest Units, too. On the other hand, the KLJN-based network (Figure 7) requires only two communicator devices for each intermediate Units and one for the end Units. The intermediate Units have to be connected only with the two nearest neighbors and the end Units of only one neighbor. That requires only 2 * (N - 1) communicator devices and (N - 1) wires. In the New York example mentioned above, the two communicator devices at each Unit and two wires at each Unit makes only about 200 thousand communicator devices and about 200 thousand cable connections, moreover, these connections are all of short distance type, connecting only the nearest neighbors. Texas A&M University, Department of Electrical and Computer Engineering Remarks If the regular network and the CS are fast enough compared to the KLJN clock, the whole network receives an N-bit long key at every (second or third) KLJN clock period. On the other hand, the whole network will receive the same key. Therefore, the system is totally secure only against external attacks: hackers from outside the network. Within the network, the security, which can be added to the network-key security, is only a regular network security protecting the information sent to/from to the CS Unit. Thus, we have the same level of security against hackers within the network, as regular networks do. What is the proper approach to encryption when we have this continuous high-speed key generation and simultaneous who le-network-key distribution? Can the generated secure bits be used to increase the security of the internal network? Higher dimensional network topologies and redundancy to protect against broken lines or Units down. This can, for example, be realized with server units with more than two (L and R) ports. The ports Pi (k) (i = 1...Q) of the k-th server can be connected to up to Q different Units. The Coordinator-server would collect the logic relations and eva luate Eq. 1, accordingly. Network redundancy and coding at higher dimensional topologies (?) This network can a lternatively be used to announce information to one or more Unit(s) or to the whole network simultaneously, in a totally secure way. Is there a need for this kind of solution? Texas A&M University, Department of Electrical and Computer Engineering U A1 B1 U A 2 B2 Texas A&M University, Department of Electrical and Computer Engineering U A1 B1 U A 2 B2 Texas A&M University, Department of Electrical and Computer Engineering Example for classical sensing: Resistor Thermometer R U = I R(T) (T) • We need to know the R(T) function. • We need to provide the accurate driving current I. • We are heating the sensor during the measurement and that causes an error. Texas A&M University, Department of Electrical Engineering and Computer Engineering Example: Thermal noise thermometry in practice R u(t) Su ( f ) = 4kTR (T) • We do not need to know the R(T) calibration function. • It is enough to measure the actual R. • We still need to provide the calibrated driving current I for the R measurement. • We are still causing an error by heating; however this error can strongly be reduced by using a resistor material of resistivity independent of temperature. Texas A&M University, Department of Electrical Engineering and Computer Engineering Thermal noise thermometry from first principles R u(t) Su ( f ) = 4kTR (T) R (T) i(t) 4kT Si ( f ) = R R= Su / Si T= Su Si 4k 1. We can determine the T and R(T) from the above equations! 2. Thus, we do not need to know the function R(T). 3. No heating because no external bias current is needed. Least perturbation of the system. Texas A&M University, Department of Electrical Engineering and Computer Engineering