Solution: Please Don’t Share Writeup – Hack The Box Crypto Challenge

Please, don't share! - Hack The Box Challenge

Hello, in today’s post I’m going to write on Hack The Box’s Crypto Challenge – Please Don’t Share!

The download section of the challenge says ” Our intelligence service intercepted these strange messages which we saved in the messages.txt file. Are you able to help us decipher them? “, it means we are going to be presented with a messag that is encrypted, we need to decrypt it.

Let’s download and see what type of message it is;

I found a text file with 4 sections, source, destination, code, public. From my initial scan using CyberChef, the first part of code and I found the message possibly in base58. BUT STILL ENCRYPTED. The second part “public” is the same so, I decided to target the first part only. , ,
51453903892 , 68647976601306097149819007990813932172694353001433054093944634

If you notice, The origin IP is always and the destination IP goes from to

After scratching my head for a while, I made an intensive google search for the name of the challenge “Please, don’t share” I found there is an encryption algorithm called “Shamir Secret Sharing“,

A poster in the HTB forum gave a hint about decryption way:

Combining the hints and Google search I made the script to give me the required prime variable. The final python script is as below:

The first part “168427778” is a decimal value of IP address. I used this website to convert IP to decilmal.

Once I have everything in place, I ran the python script, here is the output:

Then I convert the result to result to hexadecimal and then I decrypt it to ASCII.

nad we have the flag!!!!


Thanks for reading, come back for more 🙂

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Hey there, I'm Navin, a passionate Info-Sec enthusiast from Bahrain. I started this blog to share my knowledge. I usually write on HackTheBox machines and challenges, cybersecurity-related articles and bug-bounty. If you are an HTB user and like my articles, please respect here:

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