The article in this post talks about figuring out the parameters for an unknown CRC, based on sample data. Somewhat relatedly, I have an article talking about

The article in this post talks about figuring out the parameters for an unknown CRC, based on sample data. Somewhat relatedly, I have an article talking about modifying a file to generate a particular CRC, assuming that the parameters are known. https://www.nayuki.io/page/forcing-a-files-crc-to-any-value https://www.nayuki.io/page/forcing-a-files-crc-to-any-value