Kinoco HackerHands-on security practice
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CryptographyLevel 275 points

Hash Length Extension Attack

Mission

Simple signatures such as hash(secret || message) can be vulnerable to length extension attacks with Merkle-Damgard hashes. Known message and SHA-256: message = "user=guest" sha256(secret || message) = 84d89877f0d4041efb6bf91a16f0248f2fd573e6af05c19f96bedb9f882f7882 append = "&admin=true" This task checks your understanding of the attack procedure. Join the three English words naming the attack - hash, extension, attack - with underscores in lowercase and submit them as KINOCO{...}.

#cryptography#hash#sha256#length-extension

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