What is Codebusters?
Codebusters is a team cryptography event where you break encoded messages using frequency analysis, cribs, math, and cipher-specific techniques. It shows up in both middle and high school, but the cipher list and difficulty differ by division, so train from the current rules for your level.
Cipher differences by division
Always confirm against this year's official rules. These are the families teams train most.
Division B ciphers
- Aristocrats & Patristocrats
- Caesar / Affine / Atbash-style ciphers
- Vigenère and related keyword ciphers
- Baconian, Morse, and other specials in the rules
- Hill cipher when included for the season
Division C ciphers
- Harder aristocrats / patristocrats under tighter time
- Xenocrypts (Spanish frequencies + cognates)
- Affine, Vigenère, Hill, and number-theory topics as listed
- Pollux, Baconian, Porta, and other specials from the rules
- Fractionated Morse / running key variants when included
Daily: 1-2 timed aristocrats. Weekly: one mixed packet. Before invitationals: a full timed run with locked partner roles.
Rules, wiki & tools
Official rules
Current Codebusters event page from SOINC.
SOINC Codebusters →Rules manuals
Download the Div B / Div C manuals for your season.
SOINCScioly wiki
Event overview, strategies, and community notes.
Wiki: Codebusters →Toebes Codebusters
Practice tests, timers, and cipher generators.
toebes.com →Test exchange
Past tests for timed partner practice.
Scioly tests →SciOly Tutor videos
Cipher walkthroughs and timing strategy.
YouTube →