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Date: Sun, 15 May 2016 10:36:54 -0700
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From: Aaron Voisine <voisine@gmail.com>
To: Daniel Weigl <Daniel.Weigl@mycelium.com>, 
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary=94eb2c065a3833751a0532e4f488
Subject: Re: [bitcoin-dev] Bip44 extension for P2SH/P2WSH/...
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On Sun, May 15, 2016 at 5:08 AM, Daniel Weigl via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

>
> > 0x40000000 would be the next available to specify witness addresses.
> > This is compatible with existing accounts and wallet layouts.
>
> my main concern here is that
>  -) every Bip<this-bip>-compatible wallet in the future will have to
> implement all (then probably) legacy derivation and tx schemes.
>

I can see the advantage of a segwit only scheme, but we will need to
support old derivations anyway for many decades if not indefinitely. People
are using it to store value for the long term.


>  -) it does not fail in a deterministic way, if I import a seed or
> xPriv/xPub across different capable wallets.
>         It is more visible if one account has [no funds/does not show up]
> at all after an import than if something shows up but you need to make sure
> that the balance is what you might expect.
>

This is certainly a downside. It has to be weighed against the benefit of
being able to upgrade existing wallets in place. Asking users to create a
new wallet, and replace their recovery phrase backups is an even bigger
problem in my estimation.

What do you think of doing both? A new BIP43 purpose number for segwit only
wallets, but that also specifies 0x40000000/1 for the change/receive index
so that the scheme is compatible with other schemes for upgrade existing
wallets in place? There will certainly be wallet developers who decide to
upgrade in place, but we can standardized both how to indicate segwit
chains, independent of segwit only schemes or upgrade schemes, and still
have the advantages of a new segwit only BIP43 purpose number.

Aaron Voisine
co-founder and CEO
breadwallet <http://breadwallet.com/>

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div><div class=3D"gmail_signat=
ure"><div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr">On Sun, May 15, 201=
6 at 5:08 AM, Daniel Weigl via bitcoin-dev <span dir=3D"ltr">&lt;<a href=3D=
"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">bitcoin-de=
v@lists.linuxfoundation.org</a>&gt;</span> wrote:<br></div></div></div></di=
v></div><div class=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=
=3D"margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(20=
4,204,204);border-left-style:solid;padding-left:1ex"><span class=3D""><br>
&gt; 0x40000000 would be the next available to specify witness addresses.<b=
r>
&gt; This is compatible with existing accounts and wallet layouts.<br>
<br>
</span>my main concern here is that<br>
=C2=A0-) every Bip&lt;this-bip&gt;-compatible wallet in the future will hav=
e to implement all (then probably) legacy derivation and tx schemes.<br></b=
lockquote><div><br></div><div>I can see the advantage of a segwit only sche=
me, but we will need to support old derivations anyway for many decades if =
not indefinitely. People are using it to store value for the long term.</di=
v><div>=C2=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0p=
x 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border=
-left-style:solid;padding-left:1ex">
=C2=A0-) it does not fail in a deterministic way, if I import a seed or xPr=
iv/xPub across different capable wallets.<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 It is more visible if one account has [no funds=
/does not show up] at all after an import than if something shows up but yo=
u need to make sure that the balance is what you might expect.<br></blockqu=
ote><div><br></div><div>This is certainly a downside. It has to be weighed =
against the benefit of being able to upgrade existing wallets in place. Ask=
ing users to create a new wallet, and replace their recovery phrase backups=
 is an even bigger problem in my estimation.=C2=A0</div><div><br></div><div=
>What do you think of doing both? A new BIP43 purpose number for segwit onl=
y wallets, but that also specifies 0x40000000/1 for the change/receive inde=
x so that the scheme is compatible with other schemes for upgrade existing =
wallets in place? There will certainly be wallet developers who decide to u=
pgrade in place, but we can standardized both how to indicate segwit chains=
, independent of segwit only schemes or upgrade schemes, and still have the=
 advantages of a new segwit only BIP43 purpose number.</div><div><br></div>=
<div><div>Aaron Voisine</div><div>co-founder and CEO<br><a href=3D"http://b=
readwallet.com/" target=3D"_blank">breadwallet</a></div></div></div></div><=
/div>

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