You stumbled upon a group Message. Can you figure out what they were sending? The string sent is ascii encoded as a hex number (submit the ascii string as the flag)

Another RSA challenge. This time we have number of group messages, encrypted with the same small exponent (e). After doing a little bit of googling, I've found that Hastad's Broadcast Attack is able to break this encryption. You can read more about it here, at chapter 4.2.

If three parties participating in the same system encrypt the same message m using the same public exponent e=3, although perhaps different modulus n1, n2, and n3, then one can easily compute m from the three cipher texts.

Now we can look at the equations:

c1 = m^3 modulo n1

c2 = m^3 modulo n2

c3 = m^3 modulo n3

But what now? This amazing piece of code will perform the attack for us. Let's take a look at it.

Shoutout to JulesDT!

And now it's time to finally crack this message. Firstly let's create files that will hold our ciphertext and modulus n values.

Now we can use provided code to break the crypto, and get the message.

Amazing crypto challenge, and we have another flag!