Subject: Re: [bitcoin-dev] BIP 174 thoughts

From: Tomas Susanka <[email-masked]>
Date: Mon, 25 Jun 2018 21:47:59 +0200

Hi,

this is great.

On 23.6.2018 00:28, Achow101 via bitcoin-dev wrote:

> Hi all,
>
> After reading the comments here about BIP 174, I would like to propose the following changes:

From my perspective those are exactly the points I have felt strongly
about. I still think "typed records" would be a better choice, but it's
something I'm willing to compromise on. As I'm looking at the draft, we
currently have 13 records and only 3 of them have keys... Matejcik was a
bit keener on this, so we'll try to discuss this more during the week
and we also look at the draft more carefully to see if we can come up
with some nit-picks.

> - Encoding
>
> I have decided that PSBTs should either be in binary or encoded as a Base64 string. For the latter, several
> Bitcoin clients already support Base64 encoding of data (for signed messages) so this will not add any extra
> dependencies like Z85 would.

I agree. If we're arguing for not using protobuf, because it is a
dependency, we shouldn't add dependency for some lesser-known encoding
format.

As was partially brought up by William, shouldn't we consider using
bech32? It doesn't break on double-click and it is a dependency for
native Segwit addresses anyway, so wallets might already support it or
they will at some point. But we should probably run some numbers on this
first, since bech32 will obviously be larger than base64.

On 24.6.2018 10:28, Andrew Chow via bitcoin-dev wrote:

> I disagree with the idea that global types can be removed. Firstly, it
> is less of a breaking change to leave it there than to remove it
> entirely. Secondly, there may be a point in the future where global
> types would be useful/necessary. By having it still be there, we allow
> for future extensibility.

I agree. It doesn't hurt if the global section stays and it is more
forward-looking.

Best,
Tomas

PS: This email didn't get through at first, so I hope this isn't a repost.