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.
SOINC →Scioly 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 →