# Full WriteUp
Full Writeup on our website: [http://www.aperikube.fr/docs/tjctf_2018/permutation](http://www.aperikube.fr/docs/tjctf_2018/permutation)
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# TL;DR
A biais in RC4 PRNG that make us able to recover one byte of the plaintext message with statiscal analysis coupled to permutation of the message make us able to recover the initial message.