TRUC - Revision history

NotATether: Add Deployment section and expand pinning and policy from BIP 431

2026-09-13T07:38:53Z

Add Deployment section and expand pinning and policy from BIP 431

← Older revision		Revision as of 07:38, 13 September 2026
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	== Pinning context ==		== Pinning context ==

	TRUC exists mainly to make child-pays-for-parent fee bumping more reliable for contracting protocols such as the [[Lightning Network]]. Without tight topology limits, an adversary can attach many low-feerate descendants or large children that consume a node's descendant budget and block replacements. ~~Signaling version 3 opts the transaction into those limits on nodes that enforce~~ BIP 431 ~~policy. Bitcoin Core 28.0 treats version 3 transactions~~ as ~~standard on all networks~~ and ~~applies the TRUC rules~~.		TRUC exists mainly to make child-pays-for-parent fee bumping more reliable for contracting protocols such as the [[Lightning Network]]. Without tight topology limits, an adversary can attach many low-feerate descendants or large children that consume a node's descendant budget and block replacements. BIP 431 frames that class of attacks as package-limit pinning and as RBF pinning through absolute fees or conflict counts.

	Contracting protocols that pre-sign zero-fee or low-fee parents rely on a later child to carry fees. TRUC makes that topology the mempool rule rather than an informal convention.		Signaling version 3 opts the transaction into those limits on nodes that enforce BIP 431 policy. Contracting protocols that pre-sign zero-fee or low-fee parents rely on a later child to carry fees. TRUC makes that topology the mempool rule rather than an informal convention. The same design also replaces several roles that CPFP carve-out previously filled for two-party shared transactions.

	== Policy rules ==		== Policy rules ==
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	Unconfirmed TRUC ancestors and descendants must themselves be TRUC. CPFP carve-out is not granted to TRUC transactions. A TRUC transaction signals replaceability even without BIP 125 signaling. Bitcoin Core may evict an existing TRUC child when a more incentive-compatible sibling is submitted. Limited opportunistic one-parent-one-child [[Package relay\|package relay]] in Core 28.0 can pair a low-feerate parent with its child over ordinary transaction relay. The experimental <code>submitpackage</code> RPC can submit such packages to a local node.		Unconfirmed TRUC ancestors and descendants must themselves be TRUC. CPFP carve-out is not granted to TRUC transactions. A TRUC transaction signals replaceability even without BIP 125 signaling. Bitcoin Core may evict an existing TRUC child when a more incentive-compatible sibling is submitted. Limited opportunistic one-parent-one-child [[Package relay\|package relay]] in Core 28.0 can pair a low-feerate parent with its child over ordinary transaction relay. The experimental <code>submitpackage</code> RPC can submit such packages to a local node.

	Sibling eviction and inherited replaceability matter when two counterparties race to attach different fee-bumping children to the same TRUC parent. The node keeps the child that improves incentive compatibility under BIP 431-oriented policy.		Sibling eviction and inherited replaceability matter when two counterparties race to attach different fee-bumping children to the same TRUC parent. The node keeps the child that improves incentive compatibility under BIP 431-oriented policy. Because only one unconfirmed child is allowed, a counterparty cannot fill a large descendant budget with junk outputs before the honest fee-bump lands.

	~~Cluster mempool in Bitcoin Core 31.0 removes CPFP carve-out entirely, so TRUC plus~~ [[~~Package relay~~\|~~package relay~~]] ~~is the supported path for many shared~~-~~transaction fee bumps that formerly depended on carve~~-~~out~~. ~~Nodes that have not upgraded still treat version-3 transactions under older standardness rules~~, ~~so TRUC's pinning benefits apply only on~~ the ~~subset of the network that enforces BIP 431 policy~~.		[[Ephemeral_anchor\|Ephemeral anchors]] and [[Pay-to-anchor]] outputs pair naturally with TRUC parents. The parent can be below the floor while the child carries fees, and the one-parent-one-child shape matches package relay in current Bitcoin Core releases.

			== Deployment ==

			Bitcoin Core 28.0 treats version 3 transactions as standard on all networks and applies the TRUC rules. Cluster mempool in Bitcoin Core 31.0 removes CPFP carve-out entirely, so TRUC plus [[Package relay\|package relay]] is the supported path for many shared-transaction fee bumps that formerly depended on carve-out.

			Nodes that have not upgraded still treat version-3 transactions under older standardness rules. TRUC's pinning benefits therefore apply only on the subset of the network that enforces BIP 431 policy. BIP 431 itself remains an informational draft. Wallet and Lightning authors should treat topology limits as policy that can tighten or loosen slightly across releases while the <code>nVersion = 3</code> signal stays stable.

			Mining and relay still follow ordinary incentive ranking inside the allowed topology. TRUC does not guarantee confirmation. It only removes several mempool shapes that previously made fee bumps unreliable against a malicious counterparty.

	== See also ==		== See also ==
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	* [[Lightning Network]]		* [[Lightning Network]]
	* [[Transaction]]		* [[Transaction]]
			* [[Full RBF]]

	== External links ==		== External links ==
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	* [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431: Topology Restrictions for Pinning]		* [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431: Topology Restrictions for Pinning]
	* [https://bitcoinops.org/en/topics/version-3-transaction-relay/ Bitcoin Optech: Version 3 transaction relay]		* [https://bitcoinops.org/en/topics/version-3-transaction-relay/ Bitcoin Optech: Version 3 transaction relay]
			* [https://bitcoincore.org/en/releases/28.0/ Bitcoin Core 28.0 release notes]
			* [https://bitcoincore.org/en/releases/31.0/ Bitcoin Core 31.0 release notes]

	[[Category:Technical]]		[[Category:Technical]]

NotATether: Expand Policy rules on network enforcement

2026-09-13T07:35:52Z

Expand Policy rules on network enforcement

← Older revision		Revision as of 07:35, 13 September 2026
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	Sibling eviction and inherited replaceability matter when two counterparties race to attach different fee-bumping children to the same TRUC parent. The node keeps the child that improves incentive compatibility under BIP 431-oriented policy.		Sibling eviction and inherited replaceability matter when two counterparties race to attach different fee-bumping children to the same TRUC parent. The node keeps the child that improves incentive compatibility under BIP 431-oriented policy.

	Cluster mempool in Bitcoin Core 31.0 removes CPFP carve-out entirely, so TRUC plus [[Package relay\|package relay]] is the supported path for many shared-transaction fee bumps that formerly depended on carve-out.		Cluster mempool in Bitcoin Core 31.0 removes CPFP carve-out entirely, so TRUC plus [[Package relay\|package relay]] is the supported path for many shared-transaction fee bumps that formerly depended on carve-out. Nodes that have not upgraded still treat version-3 transactions under older standardness rules, so TRUC's pinning benefits apply only on the subset of the network that enforces BIP 431 policy.

NotATether: Add Pinning context and Policy rules sections

2026-09-13T07:32:53Z

Add Pinning context and Policy rules sections

← Older revision		Revision as of 07:32, 13 September 2026
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	'''TRUC''' (Topologically Restricted Until Confirmation) is an opt-in Bitcoin Core mempool policy for transactions that set <code>nVersion = 3</code>. It is described in [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431]. An unconfirmed TRUC transaction may have at most one unconfirmed parent and one unconfirmed child. The parent is limited to 10,000 vB and the child to 1,000 vB. A TRUC parent may pay below the minimum relay feerate if a package with its child meets the node's feerate rules. The policy is not a consensus change.		'''TRUC''' (Topologically Restricted Until Confirmation) is an opt-in Bitcoin Core mempool policy for transactions that set <code>nVersion = 3</code>. It is described in [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431]. An unconfirmed TRUC transaction may have at most one unconfirmed parent and one unconfirmed child. The parent is limited to 10,000 vB and the child to 1,000 vB. A TRUC parent may pay below the minimum relay feerate if a package with its child meets the node's feerate rules. The policy is not a consensus change.

			== Pinning context ==

	TRUC exists mainly to make child-pays-for-parent fee bumping more reliable for contracting protocols such as the [[Lightning Network]]. Without tight topology limits, an adversary can attach many low-feerate descendants or large children that consume a node's descendant budget and block replacements. Signaling version 3 opts the transaction into those limits on nodes that enforce BIP 431 policy. Bitcoin Core 28.0 treats version 3 transactions as standard on all networks and applies the TRUC rules.		TRUC exists mainly to make child-pays-for-parent fee bumping more reliable for contracting protocols such as the [[Lightning Network]]. Without tight topology limits, an adversary can attach many low-feerate descendants or large children that consume a node's descendant budget and block replacements. Signaling version 3 opts the transaction into those limits on nodes that enforce BIP 431 policy. Bitcoin Core 28.0 treats version 3 transactions as standard on all networks and applies the TRUC rules.

			Contracting protocols that pre-sign zero-fee or low-fee parents rely on a later child to carry fees. TRUC makes that topology the mempool rule rather than an informal convention.

			== Policy rules ==

	Unconfirmed TRUC ancestors and descendants must themselves be TRUC. CPFP carve-out is not granted to TRUC transactions. A TRUC transaction signals replaceability even without BIP 125 signaling. Bitcoin Core may evict an existing TRUC child when a more incentive-compatible sibling is submitted. Limited opportunistic one-parent-one-child [[Package relay\|package relay]] in Core 28.0 can pair a low-feerate parent with its child over ordinary transaction relay. The experimental <code>submitpackage</code> RPC can submit such packages to a local node.		Unconfirmed TRUC ancestors and descendants must themselves be TRUC. CPFP carve-out is not granted to TRUC transactions. A TRUC transaction signals replaceability even without BIP 125 signaling. Bitcoin Core may evict an existing TRUC child when a more incentive-compatible sibling is submitted. Limited opportunistic one-parent-one-child [[Package relay\|package relay]] in Core 28.0 can pair a low-feerate parent with its child over ordinary transaction relay. The experimental <code>submitpackage</code> RPC can submit such packages to a local node.

			Sibling eviction and inherited replaceability matter when two counterparties race to attach different fee-bumping children to the same TRUC parent. The node keeps the child that improves incentive compatibility under BIP 431-oriented policy.

			Cluster mempool in Bitcoin Core 31.0 removes CPFP carve-out entirely, so TRUC plus [[Package relay\|package relay]] is the supported path for many shared-transaction fee bumps that formerly depended on carve-out.


	== See also ==		== See also ==

NotATether: Expand See also links

2026-09-12T21:10:32Z

Expand See also links

← Older revision		Revision as of 21:10, 12 September 2026
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	== See also ==		== See also ==

	* [[Ephemeral_anchor]]		* [[Ephemeral_anchor\|Ephemeral anchor]]
			* [[Pay-to-anchor]]
			* [[Package relay]]
			* [[Replace by fee]]
			* [[Cluster mempool]]
	* [[Lightning Network]]		* [[Lightning Network]]
	* [[Transaction]]		* [[Transaction]]

NotATether: Add mechanism: inherited RBF, sibling eviction, package relay

2026-09-12T21:10:30Z

Add mechanism: inherited RBF, sibling eviction, package relay

← Older revision		Revision as of 21:10, 12 September 2026
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	TRUC exists mainly to make child-pays-for-parent fee bumping more reliable for contracting protocols such as the [[Lightning Network]]. Without tight topology limits, an adversary can attach many low-feerate descendants or large children that consume a node's descendant budget and block replacements. Signaling version 3 opts the transaction into those limits on nodes that enforce BIP 431 policy. Bitcoin Core 28.0 treats version 3 transactions as standard on all networks and applies the TRUC rules.		TRUC exists mainly to make child-pays-for-parent fee bumping more reliable for contracting protocols such as the [[Lightning Network]]. Without tight topology limits, an adversary can attach many low-feerate descendants or large children that consume a node's descendant budget and block replacements. Signaling version 3 opts the transaction into those limits on nodes that enforce BIP 431 policy. Bitcoin Core 28.0 treats version 3 transactions as standard on all networks and applies the TRUC rules.

			Unconfirmed TRUC ancestors and descendants must themselves be TRUC. CPFP carve-out is not granted to TRUC transactions. A TRUC transaction signals replaceability even without BIP 125 signaling. Bitcoin Core may evict an existing TRUC child when a more incentive-compatible sibling is submitted. Limited opportunistic one-parent-one-child [[Package relay\|package relay]] in Core 28.0 can pair a low-feerate parent with its child over ordinary transaction relay. The experimental <code>submitpackage</code> RPC can submit such packages to a local node.

	== See also ==		== See also ==

NotATether: Expand lead: pinning purpose and Core 28.0

2026-09-12T21:10:27Z

Expand lead: pinning purpose and Core 28.0

← Older revision		Revision as of 21:10, 12 September 2026
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	'''TRUC''' (Topologically Restricted Until Confirmation) is an opt-in Bitcoin Core mempool policy for transactions that set <code>nVersion = 3</code>. It is described in [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431]. An unconfirmed TRUC transaction may have at most one unconfirmed parent and one unconfirmed child. The parent is limited to 10,000 vB and the child to 1,000 vB. A TRUC parent may pay below the minimum relay feerate if a package with its child meets the node's feerate rules. The policy is not a consensus change.		'''TRUC''' (Topologically Restricted Until Confirmation) is an opt-in Bitcoin Core mempool policy for transactions that set <code>nVersion = 3</code>. It is described in [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431]. An unconfirmed TRUC transaction may have at most one unconfirmed parent and one unconfirmed child. The parent is limited to 10,000 vB and the child to 1,000 vB. A TRUC parent may pay below the minimum relay feerate if a package with its child meets the node's feerate rules. The policy is not a consensus change.

			TRUC exists mainly to make child-pays-for-parent fee bumping more reliable for contracting protocols such as the [[Lightning Network]]. Without tight topology limits, an adversary can attach many low-feerate descendants or large children that consume a node's descendant budget and block replacements. Signaling version 3 opts the transaction into those limits on nodes that enforce BIP 431 policy. Bitcoin Core 28.0 treats version 3 transactions as standard on all networks and applies the TRUC rules.

	== See also ==		== See also ==

NotATether: stub: TRUC (nVersion=3) 1-parent-1-child mempool policy

2026-09-03T07:25:55Z

stub: TRUC (nVersion=3) 1-parent-1-child mempool policy

New page

'''TRUC''' (Topologically Restricted Until Confirmation) is an opt-in Bitcoin Core mempool policy for transactions that set <code>nVersion = 3</code>. It is described in [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431]. An unconfirmed TRUC transaction may have at most one unconfirmed parent and one unconfirmed child. The parent is limited to 10,000 vB and the child to 1,000 vB. A TRUC parent may pay below the minimum relay feerate if a package with its child meets the node's feerate rules. The policy is not a consensus change.

== See also ==

* [[Ephemeral_anchor]]
* [[Lightning Network]]
* [[Transaction]]

== External links ==

* [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431: Topology Restrictions for Pinning]
* [https://bitcoinops.org/en/topics/version-3-transaction-relay/ Bitcoin Optech: Version 3 transaction relay]

[[Category:Technical]]