Generalized DC loop current attack against the KLJN secure key exchange scheme

A new attack against the Kirchhoff Law Johnson Noise (KLJN) secure key distribution system is studied with unknown parasitic DC voltage sources at both Alices and Bobs ends. This paper generalization of our earlier investigation a single end source. Under assumption that Eve does not know values sources, attack, utilizing current generated by dc introduced. The mathematically analyzed demonstrated computer simulations. Simple defense methods are shown. method based solely on comparison current/voltage data Alice's Bob's terminals useless here since wire currents voltages equal However, more expensive version method, which in situ simulation measurements, works efficiently.