Length extension attack. What is length extension?

When a Merkle-Damgård based hash is misused as a message authentication code with construction H(secret ‖ message), and message and the length of secret is known, a length extension attack allows…

Figure 2 from Flickr's API Signature Forgery Vulnerability

GitHub - leesangmin144/length-extension-attack

hash - Why HAIFA and sponge constructions are not prone to length extension attacks? - Cryptography Stack Exchange

HashPump - A Tool To Exploit The Hash Length Extension Attack In Various Hashing Algorithms

SOLUTION: Hash length extension attack questions - Studypool

Hash length extension attacks

Intense - Hack The Box

Hash Length Extension Attack Lab

Solved (10 Points) A server is susceptible to a hash length