09 November 2014

Caesar - 20

One of the most basic, and oldest encryption techniques is Caesar ciphering. Simply put, it's encrypted by shifting/ rotating the letters of the alphabet. So "ABC" with the Key being 5 would be encrypted as "FGH". In this particular problem, it asks:
You find an encrypted message written on the documents. Can you decrypt it? encrypted.txt
When you open the encrypted.txt page, the message says: "xliwigvixtewwtlvewimwvedlzggxbzsfazzlmjlgmdckoeftgn".

Go to Google and type 'caesar decrypt' to find an online caesar decrypting website.

I am going to be using richkni's decryptor because it brute forces the encrypted text, so I don't have to keep switching between keys to find the right one.

After pasting the message, I press submit to view all the deciphered text, each with a different shift/key. At Shift 22, I notice something interesting...

It actually looks like an English sentence! I copy the text there, remove all the spaces, and submit the passphrase, which is "RAZHVCCTXVOBWVVHIFHCIZYGKABPCJ"