Rating: 4.0

in-plain-sight


This level is simple: all you have to do is decrypt some HiddenCiphertext! To make it even easier, I'll give you everything you need, except the ciphertext; you have to find that on your own!

You will need:

Algorithm: AES-256-CBC
IV: 0a0e176722a95a623f47fa17f02cc16a

While attempting another challenge on day two, I came across an interesting article that proved crucial to solving in-plain-sight:

What is apparently plaintext, may in fact be the cipher text. And with a title 'in plain sight,' let's look for ciphertext candidates.

The 'HiddenCiphertext!' stuck out and I was guessing that it was the ciphertext. Since we need inputs to be multiples of 16, I omitted the exclamation point. Using Python, I converted the key and IV to bytes, and attempted to decrypt 'HiddenCiphertext':


>>> import binascii
>>> from Crypto.Cipher import AES