From: Peter Todd <pete@petertodd•org>
To: Andrew Poelstra <apoelstra@wpsoftware•net>,
Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Compressed Bitcoin Transactions
Date: Tue, 5 Sep 2023 18:00:33 +0000 [thread overview]
Message-ID: <ZPdswQ7uAJr35YbC@petertodd.org> (raw)
In-Reply-To: <ZPHtgiJQ4Yqrr941@camus>
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On Fri, Sep 01, 2023 at 01:56:18PM +0000, Andrew Poelstra via bitcoin-dev wrote:
> We can swag what the space savings would be: there are 122MM utxos right
> now, which is a bit under 2^27. So assuming a uniform distribution of
> prefixes we'd need to specify 28 bits to identify a UTXO. To contrast,
> to identify a blockheight we need 20 bits and then maybe 12 more bits to
> specify a TXO within a block. Plus whatever varint overhead we have.
> (I've been working on this project but busy with family stuff and don't
> remember exactly where we landed on the varints for this. I think we
> agreed that there was room for improvement but didn't want to hold up
> posting the rest of the concept because of it.)
Since most transactions spend txouts that are similar in height to each other,
you could save further bits by specifying a reference height and then encoding
the exact txout with a delta.
If you're sending multiple txins or multiple transactions in a single packet,
you could achieve this by starting the packet with the reference block height.
If your application tends to send just a single transaction, you could use a
reference height that is a function of the current time. Since sender and
receiver might not agree on the exact time, you could try slightly difference
reference heights via bruteforcing until the transaction signatures validate.
--
https://petertodd.org 'peter'[:-1]@petertodd.org
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next prev parent reply other threads:[~2023-09-05 18:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-31 21:30 Tom Briar
2023-09-01 0:49 ` Andrew Poelstra
2023-09-01 10:24 ` Fabian
2023-09-01 10:43 ` Fabian
2023-09-01 13:56 ` Andrew Poelstra
2023-09-01 14:12 ` Tom Briar
2023-09-05 18:00 ` Peter Todd [this message]
2023-09-05 18:30 ` Tom Briar
2024-01-05 15:06 ` Tom Briar
2024-01-05 15:19 ` Andrew Poelstra
2024-01-09 15:31 ` Tom Briar
2024-01-16 17:08 ` Tom Briar
2024-01-18 9:24 ` Jonas Schnelli
2024-01-19 21:09 ` Tom Briar
2023-09-01 16:56 ` Jonas Schnelli
2023-09-01 17:05 ` Tom Briar
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