Reply To: Extracurricular challenges

[upsidedown]

@Robb27 I’ll defer releasing the pseudocode for my algorithm to give people more time to solve this, but I will reveal some details.

While there are some additional optimisations for these ciphers, the core algorithm is described in #113373.

My program does a brute-force search of the entire 3×3 matrix + length 3 shift vector space (and likewise for 5×5 + 5), it doesn’t know about keywords or padding. It’s written in Rust and uses all 12 logical cores of my CPU, so you could say I am cheating a little bit by saying 10ms, it would be around 12x slower on a single core. I might investigate writing a solver in a GPU compute shader as well, since GPUs are rather good at matrix multiplication and should be able to handle larger matrices.