cryptoProhard

WannaQRy

spbctf

Task: Decrypt ECB-encrypted QR code with different key using known plaintext-ciphertext pair. Solution: Build lookup table from known pair, exploit QR structural redundancy (finder patterns), brute-force remaining unknown blocks.

$ ls tags/ techniques/
known_plaintextqr_codeblock_cipherecbimage_encryptionraw_image
known_plaintext_attackecb_codebook_attackqr_structure_analysisblock_permutation_bruteforce
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