Who can say something about this cipher disc?
A Russian cipher disk was auctioned on eBay. Does any reader know when, where and how this device was used?
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A Russian cipher disk
Now we come to the actual topic of the day. During my wanderings through the internet I came across an interesting encryption tool I didn’t know yet. It is a Russian cipher disk that was offered for a starting bid of 3600 Euro on eBay.
According to eBay, the disc is made of bronze, weighs 24 grams and measures 41×47 millimeters. It is said to have been used militarily in the late 19th and early 20th centuries.
The front of the disc shown above maps each letter of the Cyrillic alphabet to a Morse code character. This can be used to create a Caesar cipher or (if the disk is rotated from time to time) a polyalphabetic cipher. Something like this already existed in the 15th century. So this device was not particularly innovative. It offered acceptable security only if the disk was rotated after a few encrypted letters. However, a cipher disk was rarely used in this way.
The Russian army’s encryption methods were quite weak until World War I, as can be read, for example, in “The Codebreakers” by David Kahn. So this cipher disk certainly fits the picture.
The back of the disc looks much more complex:
Only one third of the underlying pane can be seen through the cover at a time.
According to the eBay description, various military signals with associated Morse code are listed here. These could be encoded with the front of the disc.
Can more be found out?
Unfortunately, there is little information on the eBay page about the history and use of this cipher disc. It is said to have been used in the Army and Navy by signalers, observers, scramblers, radio operators, and scouts. Can any reader say more about it?
If you want to add a comment, you need to add it to the German version here.
Further reading: Verschlüsselte Weihnachtspostkarte aus dem Jahr 1903 gelöst – mit überraschendem Ergebnis