HackTheBox Crypto Brainy’s Cipher Challenge

Challenge By : k4m4

Challenge Description :  Brainy likes playing around with esoteric programming. He also likes math and has therefore encrypted his very secure password with a popular encryption algorithm. Claiming that his password cannot be retrieved now, he has sent the ciphertext to some of his friends. Can you prove to Brainy that his password can actually be recovered?

Points : 30

Author : Rehman S. Beg (HTB Profile : MrReh )


Lets download the file and extract it content, we get "brainy.txt" lets see what we have inside

We got a hint from challenge name Brainfuck Cipher, so lets first decode with brainfuck cipher website link : https://www.splitbrain.org/_static/ook/

Now we get p,q,dp,dq,c if we put this on google we will find https://www.rootnetsec.com/picoctf-weird-rsa/ RSA encryption to decrypt it we will download https://github.com/lflare/picoctf_2017_writeup/blob/master/cryptography/weird-rsa/solve.py solve.py and put our values on it and run the code

here we got our flag “ch1n3z_r3m4ind3r_the0rem_r0ck$$$_9792”

FLAG : “HTB{ch1n3z_r3m4ind3r_the0rem_r0ck$$$_9792}”          

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