Hackover CTF 2015 – Racer 300 (Crypto) Write-Up

Racer (crypto 300) Category: Crypto Points: 300 Solves: 7/419 Join the race and make a round. Don't forget to view the winner animation! Hint: Just distinguish it from random data. Another hint: Accuracy not good enough? Get more pills! Yet another hint: Get the binary. Still not solved ... get the source code TL/DR For the english readers : The whole challenge consisted in making the difference between random data and data that has been generated via a RC4 stream cipher with a random key. Hopefully RC4 have some biases (paper) . One…Read more …