By deuterium.

Original description

Mceliece cryptosystem was developed in 1978 and has resisted cryptanalysis so far. Lets make allies with better error correcting codes which may call ease on the sizes of keys.

NOTE: The .sobj files were generated using Sage 10.4. It should be fine to use Sage 9.7 or onwards to parse the files.

Read this challenge as plain text or JSON.

Files

• chall.sage
• flag_enc.sobj
• params.sobj
• pubkey.sobj

Download

Sh

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mkdir -p google-ctf-2024-mceliece
cd google-ctf-2024-mceliece
curl --fail --location --output challenge.txt \
  "https://deut-erium.github.io/challenges/google-ctf-2024/mceliece/challenge.txt"
curl --fail --location --output challenge.json \
  "https://deut-erium.github.io/challenges/google-ctf-2024/mceliece/challenge.json"
curl --fail --location --output chall.sage \
  "https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/chall.sage"
curl --fail --location --output flag_enc.sobj \
  "https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/flag_enc.sobj"
curl --fail --location --output params.sobj \
  "https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/params.sobj"
curl --fail --location --output pubkey.sobj \
  "https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/pubkey.sobj"

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
• Apache-2.0
• Local Apache-2.0 license

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