**Full write-up:** [https://www.sebven.com/ctf/2021/08/29/WORMCON0x012021-Invisible-Cipher.html](https://www.sebven.com/ctf/2021/08/29/WORMCON0x012021-Invisible-Cipher.html)

Cryptography – 419 pts (10 solves) – Chall author: BUILDYOURCTF

Simple substitution cipher that can be assessed through frequency analysis. Or for the more busy (‘lazy’) people under us, a combination of quick frequency analysis and Quipqiup will do the trick just fine!

Original writeup (https://www.sebven.com/ctf/2021/08/29/WORMCON0x012021-Invisible-Cipher.html).