Generalized DC loop current attack against the KLJN secure key exchange scheme
This work addresses a critical security flaw in quantum-inspired key distribution for secure communications, representing an incremental improvement over prior attack models.
The authors tackled a security vulnerability in the KLJN secure key exchange scheme by generalizing a previous attack to include unknown parasitic DC voltage sources at both ends, demonstrating through analysis and simulations that it compromises the system, and proposed effective defense methods.
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 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.