Tag: stream cipher

Midnight CTF 2018 Finals – Snurre128

In this challenge we have a stream cipher based on LFSR and nonlinear filtering function. It has 128-bit LFSR secret state and we are also given 1600 keystream bits. Our goal is simply to recover the key which is the initial state. Here is the nonlinear filtering function: f(v) = v[0] ^ v[1] ^ v[2] …

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0CTF 2018 Quals – zer0C5 (Crypto 785)

0ops Cipher 4, hope you enjoy it:) zer0C4.zip nc 1234 Summary: related-key attack on weakened variant of RC4

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Defcon CTF Quals 2013 – All Web Challenges (3dub)

Summary: 3dub (1) – babysfirst: SQLite SQL injection 3dub (2) – badmedicine: Stream cipher bit flipping 3dub (3) – hypeman: Rack/Sinatra session secret disclosure 3dub (4) – rememberme: Bruteforce 3dub (5) – worsemedicine: Block cipher bit flipping

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