Codebusters is a three-person event where participants decode encrypted messages or encode them. Each year there are different codes that are tested. Participants usually divide up the codes so that each specializes in a few. There are always more Aristocrats than any other code, so each participant should study these.
General Resources
National Science Olympiad Page
Scioly Page
Toebes website - this has explanation of the codes, past tests as well as the ability to create new tests
Specific Resources for each code:
Atbash: simple substitution; easy to understand. Video
Caesar: simple substitution; easy to understand. Video
Aristocrat: all about guessing, substitution. There are 3 types:
Random: Video
K1: A keyword is hidden; Video
K2: Keyword is hidden in ciphertext; complicated! Video 1 and Video 2
This series of videos goes through them all, a must watch if you are working on these!
Aristocrat Misspelled: very challenging, same as Aristocrat with misspellings
Patristocrat: aristocrats without spaces; very challenging; Video
Xenocrypt: requires knowledge of Spanish: Video
Cryptarithm: math focused; can be extremely difficult. Video
Baconian: substitution with numbers. Video
Fractionated Morse: uses Morse code; complicated, takes a long time. Video
Porta: easy, uses a table. Video
Nihilist Substitution: uses a grid and math. Video
Complete Columnar: requires a little bit of guesswork; not too difficult. Video
Affine: uses math, very complicated Video