Image didn't seem to attach: [image: image.png] On Wed, 6 Feb 2019 at 09:48, Alan Evans wrote: > It's not quite enough to just do SHA512, you missed out this condition > (incredibly rare as it is): > > > In case IL is 0 or ≥n, the master key is invalid. > > Also I can't see how I would use this to seed a hardware wallet that > requires a BIP39 seed as mentioned in your abstract. > > For both of those reasons, you may want to just invent/formalize a scheme > that takes Cards -> Entropy. > From that Entropy one can generate BIP39, and non-BIP39 fans can just > continue, generate and store their root xprv. > > Prior art: Note that Ian Coleman's BIP39 site already supports Cards (and > Dice), see the logic here: > https://github.com/iancoleman/bip39/blob/master/src/js/entropy.js > > [image: image.png] > > Note it detected "full deck". It also calculates the Total Bits of Entropy > and can handle card replacement and multiple decks. > > PS, you're a bit out on your entropy calculation, log2(52!) ~= 225.58 > bits, not 219. > > > On Tue, 5 Feb 2019 at 02:08, Devrandom via bitcoin-dev < > bitcoin-dev@lists.linuxfoundation.org> wrote: > >> I would suggest 50+ 6-sided dice rolls, giving about 128 bits of >> entropy. Compared to a shuffle, it's easier to be sure that you got the >> right amount of entropy, even if the dice are somewhat biased. >> >> >> On Mon, Feb 4, 2019 at 2:33 PM James MacWhyte via bitcoin-dev < >> bitcoin-dev@lists.linuxfoundation.org> wrote: >> >>> >>> James >>> >>> >>> On Sun, Feb 3, 2019 at 10:27 AM Ryan Havar via bitcoin-dev < >>> bitcoin-dev@lists.linuxfoundation.org> wrote: >>> >>>> Conveniently a shuffled deck of cards also can serve as a physical >>>> backup which is easy to hide in plain sight with great plausible >>>> deniability. >>>> >>> >>> To make sure someone doesn't play with your cards and mix up the order, >>> use a permanent marker to draw a diagonal line on the side of the deck from >>> corner to corner. If the cards ever get mixed up, you can put them back in >>> order by making sure the diagonal line matches up. >>> _______________________________________________ >>> bitcoin-dev mailing list >>> bitcoin-dev@lists.linuxfoundation.org >>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>> >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists.linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >> >