Description: There’s tapping coming in from the wires. Additional details will be available after launching your challenge instance.
Difficulty: Medium
Author: Danny
Summary
This challenge provides a message from a remote service. The message consists entirely of dots, dashes, and spacing, a strong indicator that it is encoded using Morse Code. The goal is to decode it and extract the flag.
Analysis
Since this is an instance-based challenge, we first connect to the service using nc:
$ nc fickle-tempest.picoctf.net 60330..--. .. -.-. --- -.-. - ..-. { -- ----- .-. ... ...-- -.-. ----- -.. ...-- .---- ... ..-. ..- -. ----- ....- ...-- .- ...-- ....- ..... ----- }This is clearly Morse Code.
What is morse code?
Morse code is a method of encoding characters using sequences of short and long signals:
- Short signal = dot (
.) - Long signal = dash (
-)
Each letter or number is represented by a specific sequence of dots and dashes. Example:
- A =
.- - Kakashi =
-.- .- -.- .- ... .... ..
Spacing rules:
- Each letter is separated by a space
- Each word is separated by a slash
/(or newline)
How to encrypt using Morse Code cipher?
To encrypt text:
- Convert each letter into its dot/dash representation using the Morse table.
- Separate characters with spaces.
- Separate words using / or additional spacing.
Example:
HELLO → .... . .-.. .-.. ---
The complete table of Morse Code is :
How to decrypt Morse Code cipher?
To decrypt:
- Split the input by spaces.
- Convert each dot/dash sequence back to its letter using the Morse table.
- Join the letters to form words.
Tools such as CyberChef, DCode, or any Morse decoder can automate this process.
`
How to recognize Morse Code ciphertext?
Morse ciphertext is easy to spot:
- Contains only dots, dashes, spaces, and sometimes slashes.
- Often delivered as tapping, beeps, or light flashes.
- In text-based CTFs → sequences like:
.---- ..--- ...---.-. --- -.. .
Decrypting the Challenge Ciphertext
We paste the cipher into CyberChef using From Morse Code, which decodes it automatically:
Alternatively, here’s the manual breakdown:
-- 0 .-. ...-- -.-. ----- -.. ...-- .---- ... ..-. ..- -. ----- ....- ...-- .- ...-- ....- ..... -----M 0 R 3 C 0 D 3 1 S F U N 0 4 3 A 3 4 5 0So the decoded message is:
M0R3C0D31SFUN043A3450⚡ Raikiri🎉 Flag pwned!
Final Flag
The flag is picoCTF{M0R3C0D31SFUN043A3450}
💡 TL;DR / Lesson LearnedMorse Code uses dots and dashes to represent characters. Spacing matters: space = new letter, slash = new word. Easy to decode using CyberChef or any online Morse decoder.