What this event is about
Teams decrypt Aristocrats, Patristocrats, and other classical ciphers. Division B cipher list is in the official rules.
Study plan
Setup (team of up to 3, ~50 min; writing utensils only — no notes; ES provides resource sheets)
- Assign roles: one partner pushes Aristocrats/Patristocrats; one owns math/cipher types; one tracks specials and crib placement.
- Daily timed Aristocrats (spaces in) with frequency analysis and pattern words; remember no letter decrypts to itself.
- Patristocrats (spaces out, groups of 5, K1 alphabet) and Spanish Xenocrypt (max 1 at Regionals; 1–2 at State/Nationals) with K1 English keyword alphabets.
- Regional cipher set to master with keys/cribs as specified: Baconian (word Baconian has ≥4-letter crib), Fractionated Morse (≥4-char crib), Cryptarithms (base 10), Porta (given key), Complete Columnar (≤9 columns, crib length rule), Nihilist (given keys), Atbash, Caesar, 5×5 Checkerboard (Polybius key), Homophonic cryptanalysis (crib shows ≥3 keyword letters; keyword has 4 unique letters).
- State & National extras: Porta cryptanalysis (≥3-char crib); Nihilist cryptanalysis (crib ≥ 2× keyword length); Checkerboard cryptanalysis (two 5-letter keywords + Polybius key, ≥5-char crib); Homophonic decrypt given ≥3 keyword letters.
- Timed question #1 is always an Aristocrat — practice the signal and targeting ≤10 minutes for the timing bonus (2 × (600 − seconds)).
- Hunt the up-to-three special bonus questions (at least one Homophonic); aim for zero-error solves (150/400/750 bonus ladder).
- Score awareness: ≤2 errors = full credit on most questions; each extra error −100 (floor at 0). Cryptarithms need zero errors for full credit. Run full invitational exams as a three-person team.
Tips
Pencil lightly; erase cleanly. Don’t fight a bad tip — restart the mapping.