From: Jonas Schnelli <dev@jonasschnelli.ch>
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Date: Thu, 7 Sep 2017 09:47:16 -0700
References: <0d405f5d-c0a4-bad7-b6c3-08ba4424bf17@satoshilabs.com>
To: Pavol Rusnak <stick@satoshilabs.com>,
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
In-Reply-To: <0d405f5d-c0a4-bad7-b6c3-08ba4424bf17@satoshilabs.com>
Message-Id: <A806D2EB-744F-41A9-91C1-603F89E9005B@jonasschnelli.ch>
Subject: Re: [bitcoin-dev] Proposal: Extended serialization format for
 BIP-32 wallets
Precedence: list


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Thanks for the proposal.

Three points it could see as possible improvements:

1.
=46rom what I know, the exact birthday in seconds doesn=E2=80=99t matter =
that much therefore it may be possible to just use 13 or 16bits to =
create a representation in week from 2009-01-09 00:00 UTC. 13bits would =
give you 157 years.
Always round down to the beginning of the week when the key was created.
But not sure if it=E2=80=99s worth to save ~two bytes for that.
Also not sure if the key-birthday in seconds could have a security or =
privacy implication (week maybe better).

2.
Would it make sense to have special depth bytes that directly implies =
it=E2=80=99s a BIP44 master key (and therefore avoid the bip32 path =
serialisation)? I know some =E2=80=9Ecentralised=E2=80=9C table need to =
be available for that which may be not a good idea. But maybe the BIP =
could reserve a couple of depth-bytes (maybe 0xF0 to 0xFF) for =
predefined paths.

3.
Would adding a version bit make sense to allow future extensions?


/jonas


> Am 06.09.2017 um 15:29 schrieb Pavol Rusnak via bitcoin-dev =
<bitcoin-dev@lists.linuxfoundation.org>:
>=20
> The discussion about changing bip32 version bytes for SegWit got me
> thinking and I ended up with what I think is the best proposal:
>=20
> https://github.com/satoshilabs/slips/blob/master/slip-0032.md
>=20
> (It is hosted in SL repo for now, but if there is will, I would love =
to
> have this added to BIP repo as an extension to BIP32)
>=20
> Feel free to comment.
>=20
> --
> Best Regards / S pozdravom,
>=20
> Pavol "stick" Rusnak
> CTO, SatoshiLabs
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev


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