TY - JOUR N2 - 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 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. By using this extra information, they can reduce the duration of exchanging a single bit and in this way they achieve not only higher speed but also an enhanced security because Eve’s information will significantly be reduced due to smaller statistics. 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 this new situation, for Eve to succeed, it is not enough to find out which end has the higher resistor. Eve must exactly identify the actual resistor values at both sides. 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. In this new situation, for Eve to succeed, it is not enough to find out the resistor values at the two ends. Eve must also know the former 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 in practical applications but it is shown for the sake of ongoing discussions. L1 - http://www.czasopisma.pan.pl/Content/90109/PDF/Journal10178-VolumeXX%20Issue2_04.pdf L2 - http://www.czasopisma.pan.pl/Content/90109 PY - 2013 IS - No 2 EP - 204 DO - 10.2478/mms-2013-0017 KW - information theoretic security KW - unconditional security KW - practically perfect security KW - secure key distribution via wire KW - secure smart power grid A1 - Kish, Laszlo Bela PB - Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation DA - 2013 T1 - Enhanced Secure Key Exchange Systems Based on the Johnson- Noise Scheme SP - 191 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/90109 T2 - Metrology and Measurement Systems ER -