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Codebusters practice questions

Cryptography against the clock: aristocrats and patristocrats, Hill, affine, Baconian, Morse-based and Pollux ciphers, cryptarithms and the frequency analysis that cracks them.

Questions: 713
Division B: 135
Division C: 686
Tournaments: 42

Practice Codebusters

How you practice

Pick a division, a tournament or a question type, or let the app choose: what you miss comes back next session, what you know returns days later to check it stuck, and new questions are matched to how you are doing.

Question types

Short answer · 711
Calculation · 2

Tournaments

Scioly Summer Study Session · FlamePixel10 2026 · Div C
Scioly Summer Study Session · Ohwellz 2026 · Div C
Scioly Summer Study Session · TheBananzas 2026 · Div C
Scioly Summer Study Session · Thebluepenguin 2026 · Div B/C
Scioly Summer Study Session · worldcupfang 2026 · Div C
Scioly Summer Study Session · anonymoususer1 2025 · Div C
Scioly Summer Study Session · s034793 2025 · Div C
Scioly Summer Study Session · thenewsaddict 2025 · Div B/C
Scioly Summer Study Session · cowgazer 2024 · Div B/C
Scioly Summer Study Session · GideonB 2024 · Div C
Scioly Summer Study Session · Integral 2024 · Div C
Scioly Summer Study Session · karsi 2024 · Div B/C
Scioly Summer Study Session · Physics4kingbob 2024 · Div B
Scioly Summer Study Session · RBScioly 2024 · Div B/C
Scioly Summer Study Session · AddRidge 2022 · Div C
Scioly Summer Study Session · AnotherPenguin 2022 · Div C
Scioly Summer Study Session · Izegbuwa2004 2022 · Div C
Scioly Summer Study Session · sonia22 2022 · Div C
Scioly Summer Study Session · KingDJ777 2021 · Div C
Scioly Summer Study Session · Klebb 2021 · Div C
Scioly Summer Study Session · Name 2021 · Div C
Scioly Summer Study Session · Pieepiew 2021 · Div C
Scioly Summer Study Session · sciolyperson1 2021 · Div C
Scioly Summer Study Session · Throx 2021 · Div C
Scioly Summer Study Session · will0416 2021 · Div C
Lower Merion High School Captains' Tryout 2020 · Div C
Parkland High School Captains' Tryout 2020 · Div C
Scioly Summer Study Session · Anomaly 2020 · Div C
Scioly Summer Study Session · dragonfruit35 2020 · Div C
Scioly Summer Study Session · Name 2020 · Div C
Scioly Summer Study Session · roykim 2020 · Div C
Scioly Summer Study Session · someone1580 2020 · Div C
Scioly Summer Study Session · starchybird 2020 · Div C
Scioly Summer Study Session · Throx 2020 · Div C
Seven Lakes High School Captains' Tryout 2020 · Div C
Texas Academy of Math and Science Captains' Tryout 2020 · Div C
Ward Melville High School Captains' Tryout 2020 · Div C
Blue Valley North High School Captains' Tryout 2019 · Div C
Clements High School Captains' Tryout 2019 · Div C
Monta Vista High School Captains' Tryout 2019 · Div C
Scioly Summer Study Session · Theta 2019 · Div C
University of Florida 2019 · Div C