Nonlinearity Attack Against the Kichhoff–Law–Johnson-Noise (KLJN) Secure Key Exchange Protocol

2021 ◽  
Author(s):  
Christiana Chamon ◽  
Laszlo B. Kish
Keyword(s):  
Effective Temperature ◽  
Power Flow ◽  
Key Exchange ◽  
Information Channel ◽  
Johnson Noise ◽  
Key Exchange Protocol ◽  
Third Order ◽  
Significant Information ◽  
Total Distortion ◽  
Information Leak

This paper introduces a new attack against the Kirchhoff–Law–Johnson-Noise (KLJN) secure key exchange scheme. The attack is based on the nonlinearity of the noise generators. We explore the effect of total distortion ([Formula: see text]) at the second order ([Formula: see text]), third order ([Formula: see text]) and a combination of the second and third orders ([Formula: see text]) on the security of the KLJN scheme. It is demonstrated that as little as 1% results in a notable power flow along the information channel, which leads to a significant information leak. We also show that decreasing the effective temperature (that is, the wire voltage) and, in this way reducing nonlinearity, results in the KLJN scheme approaching perfect security.

scholarly journals Analysis of an Attenuator Artifact in an Experimental Attack by Gunn–Allison–Abbott Against the Kirchhoff-Law–Johnson-Noise (KLJN) Secure Key Exchange System

2014 ◽  
Vol 14 (01) ◽  
pp. 1550011 ◽  
Author(s):  
Laszlo B. Kish ◽  
Zoltan Gingl ◽  
Robert Mingesz ◽  
Gergely Vadai ◽  
Janusz Smulko ◽  
...  
Keyword(s):  
Correlation Time ◽  
Error Probability ◽  
Key Exchange ◽  
Johnson Noise ◽  
Exchange System ◽  
Single Loop ◽  
Design Flaw ◽  
Information Leak

A recent paper by Gunn–Allison–Abbott (GAA) [L. J. Gunn et al., Scientific Reports 4 (2014) 6461] argued that the Kirchhoff-law–Johnson-noise (KLJN) secure key exchange system could experience a severe information leak. Here we refute their results and demonstrate that GAA's arguments ensue from a serious design flaw in their system. Specifically, an attenuator broke the single Kirchhoff-loop into two coupled loops, which is an incorrect operation since the single loop is essential for the security in the KLJN system, and hence GAA's asserted information leak is trivial. Another consequence is that a fully defended KLJN system would not be able to function due to its built-in current-comparison defense against active (invasive) attacks. In this paper we crack GAA's scheme via an elementary current-comparison attack which yields negligible error probability for Eve even without averaging over the correlation time of the noise.

scholarly journals Random-Resistor-Random-Temperature Kirchhoff-Law-Johnson-Noise (RRRT-KLJN) Key Exchange

2016 ◽  
Vol 23 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Laszlo B. Kish ◽  
Claes G. Granqvist
Keyword(s):  
Power Flow ◽  
Communication Channel ◽  
Second Law Of Thermodynamics ◽  
Key Exchange ◽  
Johnson Noise ◽  
Measured Voltage ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
Set Up ◽  
Resistance Value

AbstractWe introduce two new Kirchhoff-law-Johnson-noise (KLJN) secure key distribution schemes which are generalizations of the original KLJN scheme. The first of these, the Random-Resistor (RR-) KLJN scheme, uses random resistors with values chosen from a quasi-continuum set. It is well-known since the creation of the KLJN concept that such a system could work in cryptography, because Alice and Bob can calculate the unknown resistance value from measurements, but the RR-KLJN system has not been addressed in prior publications since it was considered impractical. The reason for discussing it now is the second scheme, the Random Resistor Random Temperature (RRRT-) KLJN key exchange, inspired by a recent paper of Vadai, Mingesz and Gingl, wherein security was shown to be maintained at non-zero power flow. In the RRRT-KLJN secure key exchange scheme, both the resistances and their temperatures are continuum random variables. We prove that the security of the RRRT-KLJN scheme can prevail at a non-zero power flow, and thus the physical law guaranteeing security is not the Second Law of Thermodynamics but the Fluctuation-Dissipation Theorem. Alice and Bob know their own resistances and temperatures and can calculate the resistance and temperature values at the other end of the communication channel from measured voltage, current and power-flow data in the wire. However, Eve cannot determine these values because, for her, there are four unknown quantities while she can set up only three equations. The RRRT-KLJN scheme has several advantages and makes all former attacks on the KLJN scheme invalid or incomplete.

scholarly journals Comments on the “Generalized” KJLN Key Exchanger with Arbitrary Resistors: Power, Impedance, Security

2020 ◽  
pp. 2130002
Author(s):  
Shahriar Ferdous ◽  
Christiana Chamon ◽  
Laszlo B. Kish
Keyword(s):  
Thermal Equilibrium ◽  
Power Flow ◽  
Original System ◽  
Parasitic Capacitance ◽  
Equilibrium System ◽  
Johnson Noise ◽  
The Core ◽  
Information Leak ◽  
Selection Of ◽  
Non Equilibrium

In (Nature) Science Report 5 (2015) 13653, Vadai, Mingesz and Gingl (VMG) introduce a new Kirchhoff-law-Johnson-noise (KLJN) secure key exchanger that operates with 4 arbitrary resistors (instead of 2 arbitrary resistance values forming 2 identical resistor pairs in the original system). They state that in this new, VMG-KLJN, non-equilibrium system with nonzero power flow, the security during the exchange of the two (HL and LH) bit values is as strong as in the original KLJN scheme. Moreover, they claim that, at practical conditions, their VMG-KLJN protocol “supports more robust protection against attacks”. First, we investigate the power flow and thermal equilibrium issues of the VMG-KLJN system with 4 arbitrary resistors. Then we introduce a new KLJN protocol that allows the arbitrary choice of 3 resistors from the 4, while it still operates with zero power flow during the exchange of single bits by utilizing a specific value of the 4th resistor and a binary temperature set for the exchanged (HL and LH) bit values. Then we show that, in general, the KLJN schemes with more than 2 arbitrary resistors (including our new protocol mentioned above) are prone to 4 new passive attacks utilizing the parasitic capacitance and inductance in the cable, while the original KLJN scheme is naturally immune against these new attacks. The core of the security vulnerability exploited by these attacks is the different line resistances in the HL and LH cases. Therefore, on the contrary of the statement and claim cited above, the practical VMG-KLJN system is less secure than the original KLJN scheme. We introduce another 2, modified, non-equilibrium KLJN systems to eliminate the vulnerability against some - but not all - of these attacks. However the price for that is the loss of arbitrariness of the selection of the 4th resistor and the information leak still remains greater than zero.

Key Exchange Protocol Supporting Mobility and Multihoming

2006 ◽  
Vol 1 (2) ◽  
pp. 52-70
Author(s):  
Mohammed A. Tawfiq ◽  
◽  
Sufyan T. Faraj Al-janabi ◽  
Abdul-Karim A. R. Kadhim ◽  
◽  
...  
Keyword(s):  
Key Exchange ◽  
Key Exchange Protocol

Efficient group key exchange protocol with strong security

2010 ◽  
Vol 30 (7) ◽  
pp. 1805-1808
Author(s):  
Shao-feng DENG ◽  
Fan DENG ◽  
Yi-fa LI
Keyword(s):  
Key Exchange ◽  
Key Exchange Protocol ◽  
Group Key ◽  
Group Key Exchange
Sign in / Sign up

Export Citation Format

Share Document