To: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
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	<CAPg+sBgukwdRvfFcgdusrXoo8RiXm8OEL-WvHzjpiD8_HU5KmQ@mail.gmail.com>
From: Thomas Voegtlin <thomasv@electrum.org>
Message-ID: <0dc0336b-d590-ffe9-8689-6ae06e98a39d@electrum.org>
Date: Sun, 17 Sep 2017 10:10:17 +0200
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Subject: Re: [bitcoin-dev] proposal: extend WIF format for segwit
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On 17.09.2017 04:29, Pieter Wuille wrote:
> 
> This has been a low-priority thing for me, though, and the computation work
> to find a good checksum is significant.
> 

Thanks for the info. I guess this means that a bech32 format for private
keys is not going to happen soon. Even if such a format was available,
the issue would remain for segwit-in-p2sh addresses, which use base58.

The ambiguity of the WIF format is currently holding me from releasing a
segwit-capable version of Electrum. I believe it is not acceptable to
use the current WIF format with segwit scripts; that would just create
technological debt, forcing wallets to try all possible scripts. There
is a good reason why WIF adds a 0x01 byte for compressed pubkeys; it
makes it unambiguous.

I see only two options:
 1. Disable private keys export in Electrum Segwit wallets, until a
common WIF extension has been agreed on.
 2. Define my own WIF extension for Electrum, and go ahead with it.

Defining my own format does make sense for the xpub/xprv format, because
Electrum users need to share master public keys across Electrum wallets.
It makes much less sense for WIF, though, because WIF is mostly used to
import/sweep keys from other wallets.

I would love to know what other wallet developers are going to do,
especially Core. Are you going to export private keys used in segwit
scripts in the current WIF format?