A related task: http://rosettacode.org/wiki/Vigen%C3%A8re_cipher/Cryptanalysis We don't yet have a solution in j.
Let V be the character vector given on that web page less white space. require'plot' ROTATIONS=: >:i.50 plot ROTATIONS ; +/"1@:(="1 ROTATIONS&(|."0 1)) V shows peaks at 14 and at 42. I'd first guess the number of Caesar ciphers to be 14. After that I'd try letter pairs and know that vowels must appear fairly often. >Date: Tue, 4 Jun 2013 11:52:48 +0200 >From: Mike M?ller <[email protected]> >To: "[email protected]" <[email protected]> >Subject: [Jprogramming] Finding repeated substrings >Message-ID: <[email protected]> ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
