VULNCON 2020 was a four-day virtual hacking conference, which featured talks by researchers from the cybersec community and a jeopardy style CTF.

These were the following challenges that I solved for the CTF -

Go On a Date?

Category: Cryptography

Description

Here is your cipher!

Flag Format: vulncon{decoded_string_with_underscore}

ddve uhkft fkpjet enfqdknis

Resources

The following image was provided:

Solution

The title is “Go on a Date”, so that led me to think that this has something to do with the Date Cipher.

But we didn’t have the date yet. So after reverse searching the image, I found that this is not the original image. On comparing it with the original image, I found that there are some dots and dashes at the bottom right of the image.

Using a Morse Code Translator, I got 03202020, which is 20th March 2020.

Thus we just have to decode using using this date. I couldn’t find a decoder online, so had to do it by hand.

Flag

vulncon{date_shift_cipher_encodings}

Double

Category: Cryptography

Description

Is it Double Encoding?

6fp5ou50v5uj3x35gu4p456g4p15tv5wk5gu5b35gz4p44vm53x

Solution

The description gives us a hint, that this has something to do with Double Encoding.

After a lot of googling, I found about Twin Hex Cypher. I’ve never really heard about it, but on trying it out, we got the flag!

Flag

vulncon{Twin_Hex_Encoding_is_Hard}