Thread:4thDimensionTraveler/@comment-100.38.32.93-20170331232939/@comment-100.38.32.93-20170401003204

3. POLYBUS SQUARE, key is abcdefghijklmnopqrstuvwxy

(all letters of alphabet except z)

So 1,1 is A, 1,2 is B, 1,3 is C, etc.

If using http://crypto.interactive-maths.com/polybius-square.html to solve, uncheck use standard settings and combine y with z.

4454113454112333534454124243424432514121231131135315544254424442434432514153435432423441112551355334134243225343114454345343225134314214325134125334121554153451335144441122514442544244441534512355154321345111131121235142543153332142435144531534143451254253154433515432534144343513544

becomes

startalmostfinishedblackoutitisinshedonthirdaveworkingonastrongercipherforfuturemessagesitissurelyunbreakableitcombinesourpreviousmethodsundefinednews