Challenge archive: SekaiCTF 2023 - Diffecientwo

Challenge: Diffecientwo
Event: SekaiCTF - 2023
Year: 2023
Category: Cryptography
Authors: deut-erium
Mode: interactive
Article: https://deut-erium.github.io/challenges/sekaictf-2023/diffecientwo/
Text: https://deut-erium.github.io/challenges/sekaictf-2023/diffecientwo/challenge.txt
JSON: https://deut-erium.github.io/challenges/sekaictf-2023/diffecientwo/challenge.json

Original description:
Welcome to the Diffecientwo Caching Database API for tracking and storing content across social media. We have repurposed our [security product](https://deut-erium.github.io/challenges/sekaictf-2022/diffecient/), as saving the admin key was probably not the best idea.

We have decided to change our policies and to achieve better marketing, we are offering free API KEY to customers sharing `#SEKAICTF #DEUTERIUM #DIFFECIENTWO #CRYPTO` on *LonelyFans* (our premium business partner).

Notes:
- The original remote service is retired. Browser practice runs locally with the public dummy reward practice{local_dummy_reward}; it does not award an event solve.
- The original remote service is retired. Browser practice runs locally with the public dummy reward practice{local_dummy_reward}, not an event flag or authoritative score. No TCP endpoint is provided.

Browser practice: https://deut-erium.github.io/challenges/sekaictf-2023/diffecientwo/#browser-practice
Runtime: diffecientwo
Variants: default (first is default)
Mode describes the original interactive I/O. Start practice from the article, not a TCP client.

Challenge files (primary):
- diffecientwo.py (diffecientwo.py; handout)
  URL: https://deut-erium.github.io/assets/challenges/sekaictf-2023-diffecientwo/diffecientwo.py
  Bytes: 3226
  SHA-256: e91a6409ae1500161ce4ed455589cbe8e94aa1c803538342984c504367fdbfd3
  Upstream provenance: https://raw.githubusercontent.com/project-sekai-ctf/sekaictf-2023/4dc0f1fb2836c64b3a502e2538ba32530996b8c9/crypto/diffecientwo/dist/diffecientwo.py

Licenses (local copies):
- AGPL-3.0: https://deut-erium.github.io/assets/challenges/licenses/AGPL-3.0.txt
  Bytes: 34523
  SHA-256: 8486a10c4393cee1c25392769ddd3b2d6c242d6ec7928e1414efff7dfb2f07ef
  Upstream provenance: https://raw.githubusercontent.com/project-sekai-ctf/sekaictf-2022/383b16da68c438c5d516e6f00b2716210141f7a4/LICENSE
- CC BY-NC-SA 4.0: https://deut-erium.github.io/assets/challenges/licenses/CC-BY-NC-SA-4.0.txt
  Bytes: 19119
  SHA-256: 14d2138e3a8bd9448254f171b8e17130bf7104d2fd843ab0b924bd105fd00d5a
  Upstream provenance: https://raw.githubusercontent.com/project-sekai-ctf/sekaictf-2022/383b16da68c438c5d516e6f00b2716210141f7a4/LICENSE.content.md

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/project-sekai-ctf/sekaictf-2023/blob/4dc0f1fb2836c64b3a502e2538ba32530996b8c9/crypto/diffecientwo/README.md
Archive: https://github.com/project-sekai-ctf/sekaictf-2023/tree/4dc0f1fb2836c64b3a502e2538ba32530996b8c9/crypto/diffecientwo
Solution: https://github.com/project-sekai-ctf/sekaictf-2023/tree/4dc0f1fb2836c64b3a502e2538ba32530996b8c9/crypto/diffecientwo/solution