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ctfpal
Writeup index

Cryptography challenges

Recover a plaintext or a key from something that was supposed to protect it. In practice: identify the scheme, find the parameter the author got wrong, exploit it.

2,793 in the index. The 200 below are ranked by how many independent published solutions exist - which is the right order for learning, not for difficulty. A challenge with nine writeups gives you nine explanations of the same technique to compare; a harder one nobody documented gives you none.

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