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 defense protocol to protect against the attack. Computer simulations demonstrate that after applying the defense method the information leak becomes negligible.

翻译：我们演示了理想基尔霍夫定律-约翰逊噪声（KLJN）密钥交换器在瞬态攻击下的安全漏洞。瞬态过程始于爱丽丝和鲍勃在每个时钟周期开始时将导线连接到他们选择的电阻器。瞬态攻击发生在从爱丽丝和鲍勃端反射的瞬态信号混合之前的一段短暂时间内。信息泄露源于这样一个事实：窃听者夏娃监视电缆，并在此时间段内分析瞬态信号。我们将演示此类瞬态攻击，然后引入一种防御协议来抵御该攻击。计算机仿真表明，应用防御方法后，信息泄露变得可忽略不计。