By deuterium.

Original description

I have designed a failproof encryption system with possibly arbitrarily small public keys. I will be as famous as Et Al one day, but only if I can somehow figure out a decryption mechanism…

Read this challenge as plain text or JSON.

Files

• source.py (archived server source)
• Fixed instance (output.txt)

The flag module is needed only to generate a new instance. Solve from the source and the two lines in output.txt; no server is needed.

This fixed output was generated for the post with the unchanged original program and event flag. It is not a recording from the competition.

Download

Sh

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mkdir -p sekaictf-2022-failproof
cd sekaictf-2022-failproof
curl --fail --location --output challenge.txt \
  "https://deut-erium.github.io/challenges/sekaictf-2022/failproof/challenge.txt"
curl --fail --location --output challenge.json \
  "https://deut-erium.github.io/challenges/sekaictf-2022/failproof/challenge.json"
curl --fail --location --output source.py \
  "https://deut-erium.github.io/assets/challenges/sekaictf-2022-failproof/source.py"
curl --fail --location --output output.txt \
  "https://deut-erium.github.io/assets/challenges/sekaictf-2022-failproof/output.txt"

Check your flag

Enter the flag

The check runs locally in your browser.

Sources and solutions (spoilers)

• Full archive (may contain flags).
• Solution
• Original description or source
• Event credits
• CC BY-NC-SA 4.0 (description); AGPL-3.0-or-later (source)
• Local AGPL-3.0 license
• Local CC BY-NC-SA 4.0 license

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