👑 VIP Practice Test
Codebusters Test Curriculum Framework 4 is part of the expanded VIP practice test library — only for VIP members.
Question 1👑 VIP
In Codebusters, the Affine cipher encrypts a letter with value x using the formula E(x) = (ax + b) mod 26. What constraint must 'a' satisfy?
Remaining questions and full explanations are VIP-exclusive.