Break the weak ciphers CRIB
The workbench for the ciphers that are actually breakable: the XOR malware hides its config behind, the Caesar in a CTF puzzle. It ranks the guesses by how English they read, so the answer rises up.
Ciphertext
How it works
Why English wins
The trick to breaking XOR without knowing the key is that you do not need to recognise the right answer yourself: you let letter frequency do it. Real English is mostly a handful of letters and spaces, and almost never contains unprintable bytes, so out of 256 candidates the true plaintext scores far above the noise. That single idea, scoring by how English-like the bytes are, is what turns 256 guesses, or a whole recovered key column by column, into one answer at the top of the list.
Doing this often? OBSCURA Umbra edits a folder of code where it is and runs JavaScript, TypeScript and Python over it in a sandbox. On its own, US$4 a month; with everything else, US$9 a month or US$79 a year. 7 days free.