picoCTF - Tapping

Posted on Dec 30, 2025
  • URL: https://play.picoctf.org/practice/challenge/21
  • Title: Tapping
  • Tags: Medium, Cryptography, picoCTF 2019
  • Author: DANNY
  • Started: 27 July 2025
  • Solved: 27 July 2025
  • Description: Theres tapping coming in from the wires. Additional details will be available after launching your challenge instance.

I started the instance, and copied this nc command snippet.

alt text

The host returned this information.

buddyhearto-picoctf@webshell:~$ nc fickle-tempest.picoctf.net 53806
.--. .. -.-. --- -.-. - ..-. { -- ----- .-. ... ...-- -.-. ----- -.. ...-- .---- ... ..-. ..- -. -.-. ----. .---- ..-. -.... ..--- ----- -.... }

In primary school, I used to memorize morse code, but now I can just use online translator at this point. This is the first part before { alt text And this is the part encapsulated within {} alt text

The final flag is

PICOCTF{M0RS3C0D31SFUNC91F6206}

About Morse Code

As far as I know, Morse Code is a “language” used to translate telegraph transmission to a sequence of letters (and numbers if needed). These characters are coded to combinations of “dots”, and “dashes”. We can utilize electrical pulse, flute sound, and even eyeblinks to transmit Morse Code. Here’s the translation.

alt text

I want you to remember the easiest which is “SOS” or …—… or dot-dot-dot-dash-dash-dash-dot-dot-dot. It’s easy and it’s very important in grave danger.