cryptomedium

Двойной хэш (Double Hash)

hackerlab

Task: Flask web service with double RC4 encryption where user controls both keys. Solution: XOR cancellation attack - using identical keys (key1 == key2) causes the stream cipher to cancel itself, returning the flag in plaintext.

$ ls tags/ techniques/
sha1flaskrc4stream_cipherarc4xor_cancellationdouble_encryptionpbkdf2web_cryptoidentical_keys
RC4 stream cipher XOR cancellation attackDouble encryption with identical keysWeb service interactionHex encoding/decoding
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