cryptoPromedium

In love with space

spbctf

Task: Decrypt a message encoded as a grid of cat images in a PDF. Solution: Extract images, use known plaintext attack with frequency and context analysis to recover the substitution cipher mapping.

$ ls tags/ techniques/
known_plaintextsubstitution_cipherpdffrequency_analysisrussianimage_cipher
known_plaintext_attackfrequency_analysisimage_based_substitutioncontext_deduction
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