To: bitcoin-dev@lists.linuxfoundation.org
From: Andreas Schildbach <andreas@schildbach.de>
Date: Wed, 6 Sep 2017 00:13:12 +0200
Message-ID: <oon7hh$7b4$1@blaine.gmane.org>
References: <43636dd6-ab9e-da15-59ae-f31eb11ff7ff@electrum.org>
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Subject: Re: [bitcoin-dev] Proposal: bip32 version bytes for segwit scripts
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Generally I like the idea, but maybe we should come up with a
(Bech32-based?) new standard that also includes the key birthdate (aka
"wallet birthdate").

Also I heard Core will mix addresses of all types on the same HD chain.
What prefix would it pick? "*pub"?


On 09/05/2017 12:25 PM, Thomas Voegtlin via bitcoin-dev wrote:
> BIP32 extended public/private keys have version bytes that result in the
> user visible xpub/xprv prefix. The BIP's recommendation is to use
> different version bytes for other networks (such as tpub/tprv for testnet)
> 
> I would like to use additional version bytes to indicate the type of
> output script used with the public keys.
> 
> I believe the change should be user visible, because users are exposed
> to master public keys. I propose the following prefixes:
> 
> ========== =========== ===================================
> Version    Prefix      Description
> ========== =========== ===================================
> 0x0488ade4 xprv        P2PKH or P2SH
> 0x0488b21e xpub        P2PKH or P2SH
> 0x049d7878 yprv        (P2WPKH or P2WSH) nested in P2SH
> 0x049d7cb2 ypub        (P2WPKH or P2WSH) nested in P2SH
> 0x04b2430c zprv        P2WPKH or P2WSH
> 0x04b24746 zpub        P2WPKH or P2WSH
> ========== =========== ===================================
> (source: http://docs.electrum.org/en/latest/seedphrase.html)
> 
> I have heard the argument that xpub/xprv serialization is a format for
> keys, and that it should not be used to encode how these keys are used.
> However, the very existence of version bytes, and the fact that they are
> used to signal whether keys will be used on testnet or mainnet goes
> against that argument.
> 
> If we do not signal the script type in the version bytes, I believe
> wallet developers are going to use dirtier tricks, such as the bip32
> child number field in combination with bip43/bip44/bip49.