Date: Mon, 29 Jul 2019 03:39:15 +0000
To: Mike Brooks <m@ib.tc>
From: ZmnSCPxj <ZmnSCPxj@protonmail.com>
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Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] PubRef - Script OP Code For Public Data References
Precedence: list

Good morning Mike,

> =C2=A0 > The problem with transaction being pruned is that the data in th=
em might now be used in a *future* `OP_PUBREF`.
>
> I can see how pruning is needed for scalability, and pruning=C2=A0can be =
made compatible with a reference to a transaction. If a transaction is prun=
ed, then the key material used in a prune'ed block's PUSHDATA operations ar=
e of no value.=C2=A0 A user of the network shouldn't need to make this kind=
 of PUBREF, and if a user did want to bring a wallet back from the dead - t=
hen the utility of PUBREF wouldn't be available to them.

I believe you misunderstand the point completely.

Currently Bitcoin Core has a mode, called pruning, where:

1.  It validates ***all*** transactions.
2.  It throws away the transaction data of a block ***after*** validation.
3.  It keeps only the UTXO set of ***all*** addresses, not just a specific =
wallet.

Given the above, if a transaction block 1000 `OP_PUBREF`s to a `OP_PUSHDATA=
` in block 100, how does the pruned validator get access to this data (Whic=
h was pruned after the pruned validator handled block 100)?

Note that pruned nodes ***are*** fullnodes and validate all transactions, n=
ot just those that involve their wallet.

Regards,
ZmnSCPxj