06-09-2023, 05:04 PM
I don't think you can make a safe AND collision resistant variant of the Ethereum presale hash format. We need the entire data field to decrypt and perform the SHA3() checksum wrap and verify at the end. Without that, you would indeed be reduced to padding checks at best I suspect. Perhaps an entropy check or something could work, but you'd still be decrypting more of encseed than I think you might want to expose. Unfortunately, the process for verifying a password is to decrypt the wallet data, which means you must ship at least some of that wallet data to any system doing the cracking, and all of it if you want any reasonable certainty of finding the "right" password and not just a random string that can decrypt the data into "well formed" gibberish.