[CTF] WU - Decode me if you can

Difficulty Level : Very Easy

Challenge Category : Crypto

Description :

A message has been intercepted, but it's in a strange format. Does it mean anything to you? Perhaps an ancient method of communication could help you decipher it.
Flag format : FLAG{}

..-. .-.. .- --. – --— .-. ... ...– ..--.- -.-. --— -.. ...– ..--.- .-— ... ..--.- ...– ....- ... -.--

Solution Steps

Step 1: Identify the Encoding

The challenge hints at an "ancient method of communication," pointing towards Morse Code.
However, the ciphertext contains non-standard symbols, including:

• – (single dash-like symbol)
• --— (triple dash-like symbol)
• ..--.- (combination of dots and underscore)

These need to be normalized before decoding.

Step 2: Normalize the Symbols

Replace non-standard symbols with their standard Morse code equivalents:

1. – → - (single dash)
2. --— → --- (three dashes)
3. ..--.- → _ (underscore, often used as a separator)

After normalization, the Morse code becomes:

..-. .-.. .- --. --- .-. ... ... _ -.-. --- -.. ... _ .- ... _ ....- ... -.--

Step 3: Decode the Morse Code

Using a Morse code decoder, translate the normalized message into plain text.

Manual Decoding:

• Break the message into words and letters separated by spaces (_ is a word separator):

  ..-. .-.. .- --. --- .-. ... ... _ -.-. --- -.. ... _ .- ... _ ....- ... -.--
  

• Decode each Morse sequence:
  • ..-. → F
  • .-.. → L
  • .- → A
  • --. → G
  • --- → O
  • .-. → R
  • ... → S
  • ... → S
  • _ → Word separator
  • -.-. → C
  • --- → O
  • -.. → D
  • ... → S
  • _ → Word separator
  • .- → A
  • ... → S
  • _ → Word separator
  • ....- → 4
  • ... → S
  • -.-- → Y

Decoded Message:

FLAG M0RS3_C0D3_1S_34SY

Step 4: Format the Flag

Reformat the decoded message into the correct flag format:

FLAG{m0rs3_c0d3_1s_34sy}