Challenge archive: Google CTF 2024 - McEliece

Challenge: McEliece
Event: Google CTF - 2024 qualifiers
Year: 2024
Category: Cryptography
Authors: deuterium
Mode: offline
Article: https://deut-erium.github.io/challenges/google-ctf-2024/mceliece/
Text: https://deut-erium.github.io/challenges/google-ctf-2024/mceliece/challenge.txt
JSON: https://deut-erium.github.io/challenges/google-ctf-2024/mceliece/challenge.json

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.

Notes:
- This is a static archive. No live challenge service or runtime simulation is provided here.

Challenge files (primary):
- chall.sage (chall.sage; handout)
  URL: https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/chall.sage
  Bytes: 2385
  SHA-256: 91084a5225d4742b3483fa63a00637aff3369c79d44c633dd934528f4331cdca
  Upstream provenance: https://raw.githubusercontent.com/google/google-ctf/067421eb7e918c29e39f187fac5a0f0d72a6ab83/2024/quals/crypto-mceliece/attachments/chall.sage
- flag_enc.sobj (flag_enc.sobj; handout)
  URL: https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/flag_enc.sobj
  Bytes: 1073
  SHA-256: 27b51622f2cb72d7803a405be4651da632493422d482857316e9a6b726513019
  Upstream provenance: https://raw.githubusercontent.com/google/google-ctf/067421eb7e918c29e39f187fac5a0f0d72a6ab83/2024/quals/crypto-mceliece/attachments/flag_enc.sobj
- params.sobj (params.sobj; handout)
  URL: https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/params.sobj
  Bytes: 249
  SHA-256: eee414c4343662dbab150697b9eb371d108c2cfb19c5422a9761a455ff2a1ec7
  Upstream provenance: https://raw.githubusercontent.com/google/google-ctf/067421eb7e918c29e39f187fac5a0f0d72a6ab83/2024/quals/crypto-mceliece/attachments/params.sobj
- pubkey.sobj (pubkey.sobj; handout)
  URL: https://deut-erium.github.io/assets/challenges/google-ctf-2024-mceliece/pubkey.sobj
  Bytes: 98075
  SHA-256: f92125ca83e16afaa5ba2efda4ea8a083d8d846eae6a0cf5fdf6befb0707113d
  Upstream provenance: https://raw.githubusercontent.com/google/google-ctf/067421eb7e918c29e39f187fac5a0f0d72a6ab83/2024/quals/crypto-mceliece/attachments/pubkey.sobj

Licenses (local copies):
- Apache-2.0: https://deut-erium.github.io/assets/challenges/licenses/Apache-2.0.txt
  Bytes: 11358
  SHA-256: cfc7749b96f63bd31c3c42b5c471bf756814053e847c10f3eb003417bc523d30
  Upstream provenance: https://raw.githubusercontent.com/google/google-ctf/067421eb7e918c29e39f187fac5a0f0d72a6ab83/LICENSE

SPOILERS - organizer files and solutions
Spoilers: organizer files and upstream source, archive, or solution links may reveal answers. Modified downloads are identified below.
Source: https://github.com/google/google-ctf/blob/067421eb7e918c29e39f187fac5a0f0d72a6ab83/2024/quals/crypto-mceliece/metadata.yaml
Archive: https://github.com/google/google-ctf/tree/067421eb7e918c29e39f187fac5a0f0d72a6ab83/2024/quals/crypto-mceliece
Solution: https://github.com/google/google-ctf/blob/067421eb7e918c29e39f187fac5a0f0d72a6ab83/2024/quals/crypto-mceliece/challenge/solve.sage