Codebusters
2026 season
Type: Inquiry
Divisions: B, C
Participants: Up to 3
Approx. Time: 50 minutes
Allowed Resources: Writing utensils; up to three Class I (4/5‑function) calculators. No external notes. Verify current‑year rules.
Subsections
Edit main- AffineQuick edit
- AtbashQuick edit
- BaconianQuick edit
- CaesarQuick edit
- CheckerboardQuick edit
- Complete ColumnarQuick edit
- Fractionated MorseQuick edit
- Hill (2x2)Quick edit
- Hill (3x3)Quick edit
- K1 AristocratQuick edit
- K1 PatristocratQuick edit
- K2 AristocratQuick edit
- K2 PatristocratQuick edit
- K3 AristocratQuick edit
- K3 PatristocratQuick edit
- NihilistQuick edit
- Porta (Vigenère Variant)Quick edit
- Random AristocratQuick edit
- Random PatristocratQuick edit
- XenocryptQuick edit
Cryptography: hand ciphers, cryptarithms, and fast decoding under time pressure.
- Monoalphabetic substitution; Vigenère/Porta; Hill/Nihilist (Div C)
- Cryptarithms and logic; frequency analysis
- Team coordination for speed and accuracy
Allowed materials: Reference sheets allowed per rules; non-programmable calculator as permitted.
Official references
Sample notesheet
Download a printable, rule-compliant sample notesheet. Customize with your notes.
Study roadmap
- Build cipher cheat sheets and crib strategies
- Drill timed rounds; assign roles (freq, keys, math)
- Review error-checking routines and verification