> You have a new mission from HQ to hunt down some rogue flags. Check
> the details in the assignment. Find something good, and you'll be
> rewarded with one better
>
> HINT: flags you discover are not in flag format.
>
> nc crypto.chal.csaw.io 5000
The assignment contains a bunch of base64-encoded messages. I didn't
bother writing new code for this challenge as it's a clone of my
Cryptopals #20 solution (breaking fixed-key CTR using statistics).
Script output:
$ ruby 20.rb
[info] Max input length: 709
[info] Min input length: 134
What is real? How do yxu define real? If you're talki4g about what you can feel, what you can smell, what you ean.taste and see, then
Neo, sooner or later yxu're going to realize, just aszI did, that there's a difference between knowing the patn, ond walking the path.
The flag is: 4fb81eac0 29a -- The flag is: 4fb81eac07h9a -- The flag is: 4fb81eac0729a -- The flag is: 4fb81eae07<9a -- The flag is: 4
[...]
Obtain the flag by sending the "flag" to the online service:
$ nc crypto.chal.csaw.io 5000
Hello Morpheus. Back from the mission so quickly? I see.
Well what flags have you discovered? See, if I like what you have, I'll be willing to trade with you...