Subject: Re: [bitcoin-dev] An alternative to BIP 32?

From: Erik Aronesty <[email-masked]>
Date: Mon, 22 Mar 2021 08:05:13 -0400

yes that would be fine.    not sure what your objection to sha3 is tho
(more provably secure) - i guess sticking with bitcoin-lib stuff tho.

On Fri, Mar 19, 2021 at 10:08 PM Arik Sosman <[email-masked]> wrote:
>
> Hi Erik,
>
> Would sha256-hmac(nonce, publicKeyPoint) still be a suitable/safe alternative without relying on sha3? That should at the very least eliminate length extension attacks.
>
> Best,
> Arik
>
> > On Mar 19, 2021, at 6:32 PM, Erik Aronesty via bitcoin-dev <[email-masked]> wrote:
> >
> > use sha3-256.  sha256 suffers from certain attacks (length extension,
> > for example) that could make your scheme vulnerable to leaking info,
> > depending on how you concatenate things, etc.  better to choose
> > something where padding doesn't matter.
> >
> > On Fri, Mar 19, 2021 at 7:28 PM vjudeu via bitcoin-dev
> > <[email-masked]> wrote:
> >>
> >> I recently found some interesting and simple HD wallet design here: https://bitcointalk.org/index.php?topic=5321992.0
> >> Could anyone see any flaws in such design or is it safe enough to implement it and use in practice?
> >> If I understand it correctly, it is just pure ECDSA and SHA-256, nothing else:
> >>
> >> masterPublicKey = masterPrivateKey * G
> >> masterChildPublicKey = masterPublicKey + ( SHA-256( masterPublicKey || nonce ) mod n ) * G
> >> masterChildPrivateKey = masterPrivateKey + ( SHA-256( masterPublicKey || nonce ) mod n )
> >>
> >> Also, it has some nice properties, like all keys starting with 02 prefix and allows potentially unlimited custom derivation path by using 256-bit nonce.
> >> _______________________________________________
> >> bitcoin-dev mailing list
> >> [email-masked]
> >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
> > _______________________________________________
> > bitcoin-dev mailing list
> > [email-masked]
> > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>