Hi
> ==Generating the master mnemonic== > > The master mnemonic is first derived as a standard mnemonic as described > in BIP39. > ==From master mnemonic to derived mnemonics== > > From the master mnemonic a new string is created: > > string = MasterMnemonic + " " + Count + " " + Strength; > > Here, MasterMnemonic are the space separated words of the master > mnemonic. Count = 0, 1, 2 denotes the different derived mnemonics of a > given strength and Strength = numWords / 3 * 32, where numWords is the > number of words desired for the derived mnemonic and only integer > arithmetic is used in the calculation (e.g. for numWords = 14, Strength > = 128). Both Count and Strength are converted to strings. > > This string is then hashed using sha512: > > hash = sha512(string); 1) My humble cryptographic understanding tells me that you should probably use sha512_hmac where you add an passphrase and a salt. 2) Side-note: Bip39 does still use PBKDF2 with 2048 iterations which I personally consider "not enough" to protect a serious amount of funds. Also the checksum based on the predetermined wordlist has some security downsides over using a plain 32byte entropy (64hex chars) or a base58check encoded extended private master key. 3) Another idea: What would speak against deriving a child key after bip32, lets say at m/88'/0'/n' and use the derived 256bits to encode your mnemonic? This would at least require your master mnemonic passphrase to derive a valid "child mnemonic". 4) I'm still not convinced if we should encourage users to "only store and backup" the bip39 mnemonic. Reconstructing funds from a seed can be difficult especially if you don't have access to a trusted TX-indexed full node (~150GB of data required). Novice users might also underestimate the risk of losing metadata coupled with their transactions when they only store the wallet seed. </jonas>
signature.asc
Description: OpenPGP digital signature
_______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
