TY - JOUR N2 - A new attack against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system is studied with unknown parasitic DC-voltage sources at both Alice’s and Bob’s ends. This paper is the generalization of our earlier investigation with a single-end parasitic source. Under the assumption that Eve does not know the values of the parasitic sources, a new attack, utilizing the current generated by the parasitic dc-voltage sources, is introduced. The attack is mathematically analyzed and demonstrated by computer simulations. Simple defense methods against the attack are shown. The earlier defense method based solely on the comparison of current/voltage data at Alice’s and Bob’s terminals is useless here since the wire currents and voltages are equal at both ends. However, the more expensive version of the earlier defense method, which is based on in-situ system simulation and comparison with measurements, works efficiently. L1 - http://www.czasopisma.pan.pl/Content/114024/PDF/02_MMS_4_INTERNET.pdf L2 - http://www.czasopisma.pan.pl/Content/114024 PY - 2019 IS - No 4 EP - 616 DO - 10.24425/mms.2019.130571 KW - unconditional security KW - secure key exchange KW - parasitic loop currents and voltages KW - information leak A1 - Melhem, Mutaz Y. A1 - Kish, Laszlo B. PB - Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation VL - vol. 26 DA - 2019.12.28 T1 - Generalized DC loop current attack against the KLJN secure key exchange scheme SP - 607 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/114024 T2 - Metrology and Measurement Systems ER -