I am a mathematician, and my background is in combinatorics and statistics.
I remember reading about Jim Gillogly’s solution of the first three parts of Kryptos in 1999, on sci.crypt, and I thought that was interesting, but around then I got obsessively involved in analysis of the chess game Kasparov versus the World, so I didn’t look at K4 much myself.
I got interested in Kryptos again in June 2017 (via Google Scholar). I looked at a few classical methods proposed for breaking it, like the Hill cipher, Trifid, Gromark and four-square, and wrote some custom and hill climbing programs to help me.
My PubPeer comment on the Bauer et al paper.
2021-08-11 Chinese Whispers
2021-01-29 Military Cryptanalytics Part III
2021-01-06 Decipher Puzzle
2020-11-17 AJ Jacobs Scheidt #2
2020-11-15 AJ Jacobs Scheidt #1
2020-09-11 Response to AJ Jacobs
2020-08-25 Four thoughts
2020-07-29 Two points
2020-07-01 Response to Great Big Story
2020-06-07 Response to seriation
2020-05-18 Response to "A game for viewers"
2020-05-16 "A game for viewers"
2019-07-11 Time Magazine quote
2018-12-10 "Quest for the Golden Hare"
However, over time I've found it more interesting to work on ciphers where the method is known but new technology and methods enable solution.
Some articles about my solutions are:
I have been on the radio a few times to discuss these and other crypto mysteries