Rating:

TL;DR: $. We paid to win.

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TL;DR (of a cheaper approach):
1. Guess whether each of the hex character is a digit or a letter
2. Create (and solve) a system of linear equations base on the guess
3. ??
4. Profit!

Original writeup (https://mystiz.hk/posts/2021/2021-11-29-dragonctf-crc/).