Date: Tue, 30 Apr 2019 04:29:18 +0000
To: Aymeric Vitte <vitteaymeric@gmail.com>
From: ZmnSCPxj <ZmnSCPxj@protonmail.com>
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	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] IsStandard
Precedence: list

Good morning Aymeric,


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ssage =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90
On Monday, April 29, 2019 5:30 PM, Aymeric Vitte <vitteaymeric@gmail.com> w=
rote:

> ZmnSCPxj, OK, but you can put whatever you like in the different
> standard output script you mention (my example below whether legacy or
> segwit)
>

I am uncertain what you mean by this.

For P2PKH and P2WPKH, you must present a hash of a public key.
You cannot present a hash of anything else.

The P2PKH template can be interpreted as a script, but is actually recogniz=
ed as a template by most current nodes (in a way that is consistent with in=
terpreting it as a script).

For P2SH and P2WSH, you must present a hash of a script.

It is more helpful to consider that *today* nodes recognize particular patt=
erns (P2PKH, P2WPKH, P2SH, P2WSH) as templates and not as scripts to be exe=
cuted.

In any case, if you want to make anything more complicated than "single sig=
ner" you should use P2SH or P2WSH regardless, and give your script.
If you want to assure somebody that a particular P2SH or P2WSH commits to a=
 particular policy, just expose the policy script to them and have them (i.=
e. their client software) verify that the policy is what the user wants and=
 that when hashed it matches the P2SH/P2WSH.

As Luke said, nodes can have any policy for propagating transactions.
However it is generally expected that P2PKH, P2WPKH, P2SH, and P2WSH will b=
e propagated by a majority of nodes, if only because those are reliably "pa=
ssed" by `isStandard` in the default latest Bitcoin Core and most people wi=
ll not modify the Core code.

Generally, anything that isn't P2PKH, P2WPKH, P2SH, or P2WSH will not likel=
y be propagated by the network.
You *could* still coordinate with one or more miners to get it mined: you c=
an put anything in the block, it is simply that most nodes will not inform =
miners about transactions that do not pay out to P2PKH, P2WPKH, P2SH, or P2=
WSH.

Regards,
ZmnSCPxj