Cicada 303 Walkthrough

GCBQ1HH puzzle solve path

1Decode the ROT47 instruction

The cache page contains an encoded block of text:

%96 z6J :D >256 H:E9@FE E96 ?F>36CD[ 3FE H96C6 :D E96 z6Jn
%96 z6J H:== E2<6 J@F E@ H96C6 :E :D ?66565]
%96 7:?2= C6BF:C6D EH@ A2CED] 000000000000000i00000000000

Decode it with ROT47:

The Key is made without the numbers, but where is the Key?
The Key will take you to where it is needed.
The final requires two parts. _______________:___________
Important clue: the key is not used exactly as seen. Numbers must be removed first.

2Find the hidden ALT text

Inspect the page source and look at the image information. The hidden ALT text reads:

fubeghey.ng/bZNtT

This is ROT13. Decode it:

fubeghey.ng/bZNtT → shorturl.at/oMAgG

The short URL leads to a WAV audio file.

3Analyze the first WAV file

The WAV sounds strange, so open it in a spectrogram analyzer such as Audio Spectrogram Analyzer | Boxentriq.

  1. Open the WAV file.
  2. Switch to Spectrogram.

    The spectrogram message reads:
C303 key hint spectrogram 
AFFE3F0AD3BFCF

Use the ROT47 instruction and remove the numbers:

AFFE3F0AD3BFCF → AFFEFADBFCF

This gives the actual cipher key:

AFFEFADBFCF

4Use the key on the text clue

The linked text clue contains this encrypted line:

CNHEIALTMGWE:myxus://rvy14pi3r.htq/bp-fpsvjny/ztqodex/2026/05/IHBV1ML.bay

Use AFFEFADBFCF as a Vigenère key.

The decrypted result is:

CICADAISHERE:https://out14nd3r.com/wp-content/uploads/2026/05/GCBQ1HH.wav

This gives the first part of the final answer:

CICADAISHERE

The URL points to a second WAV file.

5Analyze the second WAV file

Open the second WAV file in a spectrogram analyzer just like before.

The hidden spectrogram message reads:

GCBQ1HH1 Spectrogram 
PARKER80134

This gives the second part of the final answer.

Certitude Answer

The ROT47 clue said the final requires two parts:

_______________:___________

Combine the two discovered parts:

CICADAISHERE:PARKER80134

Enter this into Certitude to receive the final location.

Short Solve Summary

  1. Decode the ROT47 instruction.
  2. Find the image ALT text.
  3. ROT13 the ALT text to get the short URL.
  4. Follow the short URL to the first WAV file.
  5. Read the first spectrogram: AFFE3F0AD3BFCF.
  6. Remove the numbers to get the key: AFFEFADBFCF.
  7. Use the key as a Vigenère key on the text clue.
  8. Get first part and second WAV URL.
  9. Read second WAV spectrogram: PARKER80134.
  10. Submit CICADAISHERE:PARKER80134 to Certitude.
Cicada 303 Walkthrough
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