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SIGABA Cipher Machine

This is a simulator program for the SIGABA cipher machine, also called the ECM-2.

The keyboard and mouse interface usage is similar to my ENIGMA simulators.

Full details of the history, operation and the operating procedures of the SIGABA cipher machine can be found at the references given below. The rotor wirings used here are the same as those in the Java applet referenced below.

Reports of program bugs or errors can be sent to me. (geoff@blueangel.demon.co.uk)

This simulator program is distributed by The Crypto Simulation Group:

http://home.cern.ch/~frode/crypto/

http://www.eclipse.net/~dhamer

http://www.blueangel.demon.co.uk/crypto/

This program is intended for educational and historical research purposes only and is provided and licensed 'as is' with no other warranty. It is not recommended for present day encryption use.

Summary of operation.

1.

Mode switch set to O

Machine off.

2.

Mode switch set to P

Plain text mode.

3.

889/2900 switch set to 889 or 2900

Zeroize/Operate switch set to Zeroize

Mode switch set to R

Blank or Rpt key moves all rotors to O when repeatedly pressed.

4.

889/2900 switch set to 889 or 2900

Zeroize/Operate switch set to Operate

Mode switch set to R

Keys 1-5 advances each control rotor. This is used to set the message indicator.

5.

889/2900 switch set to 889 or 2900

Zeroize/Operate switch set to Operate

Mode switch set to E

Enciphers plain text. Key letter Z is shared with X. Space is used in place of Z. The switch 889/2900 switches between the original CSP-889 machine and the modified CSP-2900 machine. An extra control was also fitted to the real machine to change the rotor motion. This switch is missing from the simulator. The 889/2900 switch provides the machine switching in this simulator.

6.

889/2900 switch set to 889 or 2900

Zeroize/Operate switch set to Operate

Mode switch set to D

Deciphers cipher text.

7.

889/2900 switch and Zeroize/Operate switch

Click the switch toggle with the mouse to change the switch position

8.

Mode switch

Click repeatedly on the required letter (O,P,R,E,D) until the switch is at the required position.

9.

Wheel positions

Click the Cipher, Control or Index wheels with the mouse to set their positions. They can be made to move forward or reverse.

10.

Inner settings menu

Select the Cipher and Control rotors, five each from the set of 10.

Select the order of the five Index rotors.

Any rotor can be reversed by selecting the appropriate R check box.

11.

Message indicator

After the Inner settings are made, the message indicator can then be set up. First  Zeroize the rotors as in part 3 above. The message indicator is given as a five letter word and is different for every message to be enciphered.  With the mode switch at R and Zeroize/Operate switch at Operate, press the numeral 1 key until the first Control rotor position corresponds to the first letter of the message indicator. Continue this procedure with numeral 2-5 keys to set the other Control rotors to the message indicator letters.  If a message indicator letter O is required then the numeral key should be pressed 26 times to set the control rotor to O. Note that the Cipher rotors will move with irregular motion during message indicator setting.

12.

Letter counter

Click with the mouse to reset the counter to zero.

Further information about the SIGABA machine, including a replica of the original operating instructions,  can be found at:

http://www.maritime.org/ecm2.htm

A Java applet simulator can be found at:

http://www.maritime.org/ecmapp.htm