settings to be used with each message. A message key was never to be used more than once. The keying material was distributed in a foil-covered package, with the daily key tables and punched cards fan-folded in a pouch with perforations between each item. The other tables were in a side pouch. Design measures against information leakage Design factors in various cryptographic devices can result in the physical leakage of information that may compromise the security of the system to varying degrees (see TEMPEST), the following describe appropriate counter measures that were taken in the design of Fialka. Power supply unit Fialka draws differing amounts of current depending on which (5-bit) encoded letter is printed or paper punched. If the power supply was plugged into the mains there would be an opportunity for the small power fluctuations to be observed by an eavesdropper. In order to mask any mains supplied power fluctuations a data cable fed back from the Fialka machine to the power supply unit indicating which letter was being output allowing the supply to compensate for the differing loads. The supply was designed with a compensating circuit with five artificial load resistors which would be powered depending on the signal from the feedback cable. Comparison with other rotor machines The Fialka design seems to derive from the Swiss NEMA, but the NEMA only has 5 electrical rotors vs. the Fialka's 10 and NEMA lacks a punched card commutator or an equivalent, such as a plug board. Fialka seems most comparable to the U.S. KL-7 which has eight electrical rotors and also lacks a commutator, but its keyboard permutor switch eliminated the need for a reflector, which proved to be a weakness in the Enigma system. See also Enigma NEMA References Further reading Scanned PDF from Dr. Tom Perera. External links The M-125-3 Fialka cipher machine — German Spy Museum Berlin Russian Fialka ( = Violet ) 10-Rotor Device — by Nick Gessler Russian M-125 Fialka — by Jerry Proc Simulation of M125MN and M125-3MN find under Cryptographic hardware Rotor machines Science and technology in the Soviet Union Soviet inventions KGB Communications in the Soviet Union Warsaw Pact