upx Posted November 3, 2022 Share Posted November 3, 2022 For challenge #9: Spoiler I've identified the symmetric cipher used as probably being ChaCha20 and other basic usage. The other values in the encrypted file also seem to be relevant but I'm not sure how everything ties together. Two of the byte arrays seem to be always constant, the second is used for the asymmetric stuff and the fourth might be an encrypted key? It's difficult to single-step through all the mathematical operations and make sense of everything. I can link some similarities between the value used to generate unk_404020 and the second byte array like the last N or so bytes being the same, but not sure how I could use that to extract the key from the 1024-bit value. Link to comment Share on other sites More sharing options...
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