We introduce seven new versions of the Kirchhoff-Law-Johnson-(like)-Noise (KLJN) classical physical secure key exchange scheme and a new transient protocol for practically-perfect security. While these practical improvements offer progressively enhanced security and/or speed for the non-ideal conditions, the fundamental physical laws providing the security remain the same.
In the "intelligent" KLJN (iKLJN) scheme, Alice and Bob utilize the fact that they exactly know not only their own resistor value but also the stochastic time function of their own noise, which they generate before feeding it into the loop.
In the "multiple" KLJN (MKLJN) system, Alice and Bob have publicly known identical sets of different resistors with a proper, publicly known truth table about the bit-interpretation of their combination. In the "keyed" KLJN (KKLJN) system, by using secure communication with a formerly shared key, Alice and Bob share a proper time-dependent truth table for the bit-interpretation of the resistor situation for each secure bit exchange step during generating the next key.
The remaining four KLJN schemes are the combinations of the above protocols to synergically enhance the security properties. These are: the "intelligent-multiple" (iMKLJN), the "intelligent-keyed" (iKKLJN), the "keyed-multiple" (KMKLJN) and the "intelligent-keyed-multiple" (iKMKLJN) KLJN key exchange systems.
Finally, we introduce a new transient-protocol offering practically-perfect security without privacy amplification, which is not needed at practical applications but it is shown for the sake of ongoing discussions.
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 (TD) at the second order (D2), third order (D3), and a combination of the second and third orders (D2,3) on the security of the KLJN scheme. It is demonstrated that a 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 paper demonstrates the vulnerability of the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchanger to compromised random number generator(s) even if these random numbers are used solely to generate the noises emulating the Johnson noise of Alice's and Bob's resistors. The attacks shown are deterministic in the sense that Eve's knowledge of Alice's and/or Bob's random numbers is basically deterministic. Moreover, no statistical evaluation is needed, except for rarely occurring events of negligible, random waiting time and verification time. We explore two situations. In the first case, Ev…
Analysis of an attenuator artifact in an experimental attack by Gunn-Allison-Abbott against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system
Gunn-Allison-Abbott（GAA）最近的一篇论文[L. J. Gunn等人，Scientific Reports 4（2014）6461]认为基尔霍夫定律-约翰逊噪声（KLJN）安全密钥交换系统可能经历严重的信息泄漏。在这里，我们反驳他们的结果，并证明GAA的论点随之而来的一个严重的设计缺陷，在他们的系统。具体地，衰减器将单个基尔霍夫环路分成两个耦合环路，这是不正确的操作，因为单个环路对于KLJN系统中的安全性是必不可少的，因此GAA声称的信息泄漏是微不足道的。另一个后果是，一个完全防御的KLJN系统将无法正常工作，因为它内置了针对主动（入侵）攻击的电流比较防御。在本文中，我们破解GAA的计划通过一个基本的电流比较攻击，产生可以忽略不计的错误概率夏娃，即使没有平均的相关时间的噪声。
This paper introduces and demonstrates four new statistical attacks against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange scheme. The attacks utilize compromised random number generators at Alice's/Bob's site(s). The case of partial correlations between Alice's/Bob's and Eve's probing noises is explored, that is, Eve's knowledge of Alice's and Bob's noises is limited but not zero. We explore the bilateral situation where Eve has partial knowledge of Alice's and Bob's random number generators. It is shown that in this situation Eve can crack the secure key bit by taking the highest…
What kind of noise guarantees security for the Kirchhoff-Loop-Johnson-Noise key exchange?
本文是对我们最近一篇关于Kirchhoff-Law-Johnson-Noise（KLJN）安全密钥交换系统中噪声特性分析的补充[Gingl and Mingesz，PLOS ONE 9（2014）e96109，doi：10.1371/journal.pone.0096109]。在这里，我们使用纯粹的数学统计推导来证明，只有正态分布与特殊的缩放可以保证安全。我们的结果与早期的物理假设一致[Kish，Phys. Lett. A 352（2006）178 - 182，doi：10.1016/j.physleta.2005.11.062]。此外，我们已经进行了数值模拟表明，通信显然是不安全的噪声属性的选择不当。本文没有考虑使用时间和相关性分析来防止攻击。
Notes on Recent Approaches Concerning the Kirchhoff-Law-Johnson-Noise-based Secure Key Exchange
我们批判性地分析了[Physics Letters A 373（2009）901-904]中的结果和主张。我们表明，在模拟中出现的强大的安全漏洞只是一个文物，而不是由“多次反射”。由于在信号最短波长5%的电缆长度处不存在波模式，因此不存在波来反射它。在高波阻抗限制下，模拟中使用的条件严重非物理（要求电缆直径比已知宇宙的测量尺寸大28000倍），结果是由于非物理值而产生的建模伪影。在低电缆阻抗限值下，观察到的伪影是由于违反了推荐（和测试）条件，忽略了电缆电容限制，并使用了比推荐长约100倍的电缆，而没有电缆电容补偿装置。我们实现和分析了刘的循环器的一般电路，并确认它们在概念上是安全的，对被动攻击。我们引入了一个不对称的，更强大的版本没有反馈回路。然后我们通过主动攻击来破解所有这些系统：基于循环器的中间人攻击。最后，我们分析了所提出的方法，以提高安全性，只丢弃高风险位。我们指出了不同类型的高风险比特之间的差异，并显示了一些简单的密钥交换协议的这种策略的不足。
Utilizing a formerly published cold resistor circuitry, a secure key exchange system is conceived and explored. A circuit realization of the system is constructed and simulated. Similarly to the Pao-Lo key exchanger, this system is secure in the steady-state limit but crackable in the transient situations.
This dissertation demonstrates three new types of attacks against the KLJN scheme. The first attack type is based on compromised RNGs. The first RNG attacks are deterministic. First, Eve knows both noises. She can crack the bit via Ohm's Law and one-bit powers within a fraction of the bit exchange period. Second, Eve knows only Bob's noise, so she can learn Bob's resistance value via Ohm's Law and Alice's resistance at the end of the bit exchange period. She can also use a process of elimination. The second RNG attacks are statistical. First, Eve has partial knowledge of Alice's and Bob's nois…
Generalized DC loop current attack against the KLJN secure key exchange scheme
研究了一种新的对基尔霍夫定律-约翰逊噪声（Kirchhoff Law Johnson Noise，KLJN）安全密钥分发系统的攻击方法，该方法在Alices和Bobs两端引入未知的寄生直流电压源.本文是我们早期的调查与单端寄生源的推广。假设夏娃不知道的寄生源的值，一个新的攻击，利用寄生直流电压源产生的电流，介绍。该攻击是数学分析和演示的计算机模拟。简单的防御方法对攻击显示。早期的防御方法仅基于Alice和Bob的端子处的电流/电压数据的比较在这里是无用的，因为导线电流和电压在两端是相等的。然而，更昂贵的版本的早期防御方法，这是基于现场系统模拟和比较与测量，有效地工作。
In this paper, the vulnerability of the Vadai, Mingesz and Gingl (VMG)- Kirchhoff-Law-Johnson-Noise (KLJN) Key Exchanger (Nature, Science Report 5 (2015) 13653) against two active attacks is demonstrated. The security vulnerability arises from the fact that the effective driving impedances are different between the HL and LH cases for the VMG-KLJN scheme; whereas for the ideal KLJN scheme they are same. Two defense schemes are shown against these attacks but each of them can protect against only one of the attack types; but not against the two attacks simultaneously. The theoretical results ar…
The information theoretically secure Kirchhoff-law-Johnson-noise (KLJN) key exchange scheme, similarly to quantum key distribution (QKD), is also potentially vulnerable against clock attacks, where Eve takes over the control of clock synchronization in the channel. This short note aims to introduce a time synchronization protocol scheme for Alice and Bob, which is resistant against arbitrary time delay attacks, both symmetric and asymmetric ones. We propose and explore various ways of clock synchronization for the KLJN system and propose an ultimate protocol that preserves time and hardware in…
We demonstrate the security vulnerability of the ideal Kirchhoff-Law-Johnson-Noise (KLJN) key exchanger against transient attacks. Transients start when Alice and Bob connect the wire to their chosen resistor at the beginning of each clock cycle. A transient attack takes place during a short duration of time, before the transients reflected from the end of Alice and Bob mix together. The information leak arises from the fact that Eve (the eavesdropper) monitors the cable, and analyzes the transients during this time period. We will demonstrate such a transient attack, and, then we introduce a …
Background: The kidney exchange problem (KEP) addresses the matching of patients in need for a replacement organ with compatible living donors. Ideally many medical institutions should participate in a matching program to increase the chance for successful matches. However, to fulfill legal requirements current systems use complicated policy-based data protection mechanisms that effectively exclude smaller medical facilities to participate. Employing secure multi-party computation (MPC) techniques provides a technical way to satisfy data protection requirements for highly sensitive personal he…
Quantum networks open the way to an unprecedented level of communication security. However, due to physical limitations on the distances of quantum links, current implementations of quantum networks are unavoidably equipped with trusted nodes. As a consequence, the quantum key distribution can be performed only on the links. Due to this, some new authentication and key exchange schemes must be considered to fully benefit from the unconditional security of links. One such approach uses Multiple Non-Overlapping Paths (MNOPs) for key exchange to mitigate the risk of an attack on a trusted node. T…
