Three years ago in 2022, when I was part of the Sprint Teams (Storm was the best team!), my colleague Miltos, who happened to be also my line manager, posted the following challenge into one of the group channels. Me not knowing much about RSA (except of that it’s an algorithm to encrypt data lol), but also loving everything about Cyber Security, I took on the challenge right away!

It’s your turn now and all you need is Google, good luck! :computer: :closed_lock_with_key: :mag:


:lock: The Challenge

For next week I have something more on the fun side I hope, as you will have to crack the RSA encryption :stuck_out_tongue: I have encrypted my lucky number using the public key below

modulus : 2459871053643326429
e       : 17

The encrypted value is

35632720329943226

silly me however picked a rather small key size for our current hardware capabilities, and should be able to be cracked within seconds. All you need is to understand how RSA works! (i guess if you know already what my lucky number is you get a free pass on this)


:key: Answer

Click to reveal the answer
Are you sure?
The number has 7 digits
It starts with 151..... The lucky number is 1512720


I hope you had as much fun as I had cracking the algorithm! Check out the next post for my solution.