Fialka (M-125) is the name of a Cold War-era Soviet
cipher machine. A rotor machine, the device uses 10 rotors, each with
30 contacts along with mechanical pins to control stepping. It also
makes use of a punched card mechanism.
Fialka means "violet" in
Russian. Information regarding the machine was quite scarce until c.
2005 because the device had been kept secret.
Fialka contains a five-level paper tape reader on the right hand side
at the front of the machine, and a paper tape punch and tape printing
mechanism on top. The punched-card input for keying the machine is
located on the left hand side. The
Fialka requires 24 volt DC power
and comes with a separate power supply that accepts power at 100 to
250 VAC, 50–400 Hz.
The machine's rotors are labelled with Cyrillic, requiring 30 points
on the rotors; this is in contrast to many comparable Western machines
with 26-contact rotors, corresponding to the Latin alphabet. The
keyboard, at least in the examples of East German origin, had both
Cyrillic and Latin markings. There are at least two versions known to
exist, the M-125-MN and the M-125-3MN. The M-125-MN had a typewheel
that could handle Latin and Cyrilic letters. The M-125-3MN had
separate typewheels for Latin and Cyrilic. The M-125-3MN had three
modes, single shift letters, double shift with letters and symbols,
and digits only, for use with code books and to superencrypt numeric
1 Encryption mechanism
2 Keying material
3 Comparison with other rotor machines
4 See also
6 External links
Fialka rotors fitted inside the machine.
Rotor stack removed from the machine, showing the 30 contact pins.
Fialka rotor assembly has 10 rotors mounted on an axle and a 30 by
30 commutator (Kc 30x30). The commutator consists of two sets of 30
contact strips set at right angles to each other. A punched card is
placed between the two sets of contacts via a door on the left hand
side of the unit. Each punched card has 30 holes, with exactly one
hole per row and column pair, and thereby specifies a permutation of
the 30 rotor contact lines. This feature is comparable to the plug
board on the Enigma machine. A triangular plate was used to enter the
null permutation for testing purposes.
There are two types of rotors:
disassemblable (zerlegbar) rotors, used with M-125-3MN. Rotorset name
is "PROTON." The disassemblable rotors consisted of an insert with
electrical contacts and scramble wiring, and an outer ring with
mechanical pins whose presence or absence controlled rotor stepping.
As part of the key setup, the stepping control pins could be rotated
relative to the outer ring. The inner, electrical ring could also be
rotated relative to the outer ring and could be inserted in one of two
ways, with side 1 or side 2 up.
unitary rotors, used with M-125-MN. These had both electrical contacts
and mechanical pins. The only key adjustment was the order of the
rotors on the axle and the initial rotor settings. There was one
combination for the disassemblable rotors that was compatible with the
unitary rotor. One East German manual that has become public contains
typed-in and hand written addenda that suggest the East Germans, at
least, later stopped using the added features of the disassemblable
rotors and only used them in unitary compatibility mode.
Adjacent rotors step in opposite directions. A spare rotor assembly
was kept in unit's top cover.
The keying material for the
Fialka consists of a daily key book, a
message key book and a message identifier book for broadcast traffic.
The daily key book contains day keys for one month. A day key consists
of a key table (in Cyrillic) and a punched card. For fixed rotor
systems, the key table specifies the order of the rotors on the axle
and the initial rotor settings to be used to decrypt the indicator of
broadcast messages. As its name implies, the day key is valid (has a
cryptoperiod in NSA parlance) for 24 hours and was changed at 00:01
hours. For the disassemblable rotors, the table also specifies the
electrical insert for each outer rotor, which side was to be up, and
the orientation of the insert relative to the outer rotor. Here is a
sample M-125-3NM day key table for use on the 14th of the month:
ИДЖЗА ВКБГЕ 14
The message key table contained the initial rotor 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.
Comparison with other rotor machines
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.
KL-7 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.
M-125 Operation (Nutzung) manual, DV A 040/1/321, December 1978,
National People's Army,
German Democratic Republic
German Democratic Republic (German, with
updates), scanned PDF from Dr. Tom Perera, 
Fialka Cipher Machines — by Tom Perera
Fialka M-125 on the Crypto Museum website
Fialka Cipher Machines — by Nick Gessler
RUSSIAN M-125 FIALKA — by Jerry Proc
A Simulation of M125MN and M125-3MN find under 
Fialka: The Bigger, Better, Russian Enigma 
Fialka in the German Spy Museum
Lorenz SZ 40/42
Siemens and Halske T52
Sectéra Secure Module
In Computer Hardware
AES instruction set
Intel SHA extensions
History of cryptography
Outline of cryptography
Cryptographic hash function
Message authentication code