Applet copied with permission. Thank you USS
Pampanito!
This program emulates the operation of an ECM Mark II model CSP 889/2900
(a.k.a SIGABA).
This is a complicated applet. Please read these instructions:
1) Change the Zeroize/Operate choice to Operate. Note the non-functional middle position mimics the middle position of the real machine. The controls of this program do not look like the controls on the real machine, but they work the same. This includes many of the oddities of the real machine that could cause accidental errors, slow you down, etc.
2) Change the CSP 889/CSP 2900 choice to CSP 889.
3) Change the master switch (found in the upper right) to:
O for Off
P for Plain text, what you type gets printed.
R for Reset position. Don't use this. It allows the 1-5
keys to set the control rotors to a key.
E for Encrypt
D for Decrypt
4) Set the rotors. Enter five etters (the encryption key) into the two boxes at the top of the column of three text boxes in the center. This is the encryption key. After changing any text box you must press enter while in the box.
4) Operate. Type or set the rotors, depending on the setting
of the master switch.
Example:
1) Complete steps 1 and 2 of the instructions above.
2) Set the top key box to "TALES" and middle key box "SELAT". After entering each key, press enter in the text box. The lower one should remain at "00000."
3) Set the master switch to "D" for Decrypt.
4) Punch "TMYHN BHWNT CDMAN HCSBN" into the keys. Spaces do not matter. You have to click each key with your mouse.
Surprise!
There are other features in the SIGABA, but those are designed for people who are doing heavy-duty encryption and decryption with it. You need not worry about them. Don't encrypt any important information with SIGABA. It is not a secure cipher.