Mommy Morse

hardware radio FCSC 2022 solved on

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Description

You need to send a message in Morse code with a two-state frequency modulation. The chosen encoding is as follows: the . and - are represented by a pure carrier at a frequency of 5kHz, and the gaps are represented by a pure carrier at a frequency of 1kHz.

You must send CAN I GET THE FLAG.

You have the server code and a sample message available.

The transmission parameters are as follows:

  • sampling rate: 24kHz,
  • sending of a .: pure carrier of frequency 5kHz during 1 millisecond,
  • duration of a -: pure carrier of 5kHz frequency for 5 milliseconds,
  • spacing between two letters: pure carrier of frequency 1kHz during 5 milliseconds,
  • spacing between two words: pure carrier of frequency 1kHz during 20 milliseconds.

This challenge has been split into three parts:

Files

  • docker-compose.yml
  • mommy-morse.py
    3.83 KiB – 9e372d5244e6a1eab67cafeae3abb53daadeb4e61c154ce18f222f73e574f3e5
  • client.py
    312 B – e23fa175a943fb6943918e9a2ba3cef3d37678a151047aae962fd23ada3f17d5
  • signal.iq
    11.53 KiB – abaf0cabdda55a40f9707ea12813ab701b3b052142af9838a282199835416695

Author

ElyKar

Challenge Instructions

  1. First, download docker-compose.yml:
    curl https://hackropole.fr/challenges/fcsc2022-hardware-mommy-morse/docker-compose.public.yml -o docker-compose.yml
  2. Launch the challenge by executing in the same folder:
    docker compose up
  3. Then, in another console, access the challenge with Netcat:
    nc localhost 4000
⚠️ Important: You must solve the challenge by interacting with the Docker container through the exposed network port. Any other way is not considered valid.

In case you encounter problems, please consult the FAQ.

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Writeups

I've been looking for a long time and I still can't find the flag!

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DateAuthor Language Tags Vote
2023-11-29
ribt
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