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Codebusters (Trial)

Division: A- Elementary School

NC Essential Standards Alignment: Science as Inquiry

Event Rules: Codebusters A Rules 2021

Event Score Sheet: None

Clarifications: None


Teams will cryptanalyze (decode) encrypted messages using cryptanalysis techniques and show skill with ciphers by decrypting a message.


Teams must bring a writing utensil. No other resources are allowed.


High score wins

Common Mistakes:

  • Students do not have to work through each cipher together – divide and conquer the test!  You are allowed to take it apart.


Will the students be given the Caesar offset number or will they have to figure it out?

– If we give the Caesar offset, it will be worth less than if we don’t, but they might see it both ways!

What is the best way to study for this test?

  • make test in the Codebusters tool – this is how all the tests will be made this year, so students should get used to the format.  They can make ciphers for each other too – you can’t break it, let them take a sentence and change the cipher type to see how it changes what will print on the page!

Fast Facts:


Event Resources:

The State event supervisor for Codebusters has set up a twitter handle to send out tips and tricks.  @NCSO_cb
Important update from the Coaches institute.  The K2 alphabet hint is actually a K1 alphabet hint.  Everything described works the same, just the label is a K1 instead of K2.  You can read on how to solve with a K1 alphabet at
Previous tests can be found at
CIA – break the code
The Imitation Game
Hill Cipher
Affine Cipher
   Encode/Decode Tool:
Vigenere Cipher