From: defenwycke <cal.defenwycke@gmail.com>
To: Bitcoin Development Mailing List <bitcoindev@googlegroups.com>
Subject: [bitcoindev] Draft BIP: DustSweep – policy-only UTXO dust compaction
Date: Thu, 11 Dec 2025 04:53:18 -0800 (PST) [thread overview]
Message-ID: <b47aa182-bca7-44d7-bed1-f3cc2df30ef5n@googlegroups.com> (raw)
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Hello list,
I’ve been working on a small policy proposal that aims to address one very
specific problem: the long-term accumulation of uneconomical dust in the
UTXO set.
The idea is intentionally narrow. I’m calling it DustSweep, and it defines
a strict, non-abusable class of transactions that nodes may relay and
miners may include only when the mempool and block space are underutilised.
The goal is to give wallets a predictable way to compact dust without
introducing new spam vectors or touching consensus.
A DustSweep transaction has the following properties:
-
all inputs are “dust-class” UTXOs
-
only standard scripts (P2PKH / P2WPKH / P2TR)
-
exactly one output
-
no metadata at all (no OP_RETURN, inscriptions, TLVs, etc.)
-
minimum of 5 inputs (to ensure meaningful UTXO reduction)
-
size capped
-
it pays a flat 1 sat per input fee
Nodes place these in a small, separate sub-mempool. They’re only accepted
when the normal mempool is <50% full, and they’re automatically evicted if
normal mempool usage hits 95%. Miners can include them up to a small weight
fraction (I suggest ~5%) but only after filling the block with regular
fee-paying transactions. The intention is that DustSweep never competes
with the fee market and only uses blockspace that would otherwise go unused.
This is all policy-level. No consensus changes, no new transaction format,
nothing that affects validation. Nodes that don’t implement it simply treat
these as low-fee transactions and drop them.
The motivation is straightforward: we don’t currently have a safe,
structured way to compact dust, and the UTXO set continues to grow from
outputs that are effectively unspendable under normal fee conditions.
DustSweep tries to offer a predictable, opt-in mechanism for wallets to
clean that up without creating any new attack surface.
Full draft BIP and supporting documents are here:
https://github.com/defenwycke/bip-dust-sweep
I’d appreciate feedback on the policy details, thresholds, and whether this
fits within what node operators and wallet developers would actually want
to use. Happy to adjust parameters if there’s a better balance point.
Kind regards,
Defenwycke
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next reply other threads:[~2025-12-11 13:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-11 12:53 defenwycke [this message]
2025-12-12 18:10 ` [bitcoindev] " Jonathan Voss
2025-12-12 20:17 ` Defenwycke
2025-12-12 22:49 ` [bitcoindev] " Murch
2025-12-13 14:56 ` defenwycke
2025-12-22 19:06 ` Murch
2025-12-22 19:33 ` Defenwycke
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