Something different for Historians - Interesting account of the Playfair Cipher used in WW1.
-
Playfair article Link: https://en.wikipedia.org/wiki/Playfair_cipher
Mentioned in the article that Computer-run block ciphers work in a manner similar to Playfair’s. I would not know where to begin to understand this!
Link for diary page: ttps://talk.operationwardiary.org/#/subjects/AWD0003d2a
Posted
-
by
ral104
moderator, scientist
Very interesting. Before these sorts of ciphers it was common to encode messages using simple substitution ciphers, whereby each letter was replaced by a different letter a certain number of places away from it in a standard alphabet. Julius Caesar is known to have encoded messages this way, and the technique held for centuries afterwards.
The block ciphers you mention are similar in some ways, in that blocks of text are encoded together according to certain rules. Playfair is a simple example of that, as it encodes pairs of letters from a message, rather than each letter individually.
Encoding messages using Playfair was apparently easy to learn, but I can't quite imagine encoding by hand while under fire.
Posted
-
by
David_Underdown
moderator
Playfair turns up in one of the Lord Peter Wimsey books (possibly "Have his carcase"), Wimsey having been an intelligence officer during the war.
Posted
-
Thank you Ral and David for your replies.
Posted
-
by
ral104
moderator, scientist
I haven't read the Lord Wimsey books - I think I'll check them out. Thanks, David.
Posted