Pay-to-anchor - Revision history

NotATether: Add Template and Use with TRUC sections

2026-09-13T07:30:34Z

Add Template and Use with TRUC sections

← Older revision		Revision as of 07:30, 13 September 2026
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	'''Pay-to-anchor''' (P2A) is a keyless native [[Segregated Witness]] version 1 output type described by [https://github.com/bitcoin/bips/blob/master/bip-0433.mediawiki BIP 433]. The scriptPubKey is <code>OP_1 <0x4e73></code>, serialized as the bytes <code>0x51 0x02 0x4e 0x73</code>. On mainnet the corresponding [[Bech32m]] address is <code>bc1pfeessrawgf</code>. Spending requires an empty witness. Anyone able to broadcast a child that spends the output can attach fees. P2A names the output template. It is not the same as a keyed Lightning <code>option_anchors</code> output, and it is not the same as an [[Ephemeral_anchor\|ephemeral anchor]], which is a usage pattern that combines a P2A output with [[TRUC]] policy and ephemeral dust.		'''Pay-to-anchor''' (P2A) is a keyless native [[Segregated Witness]] version 1 output type described by [https://github.com/bitcoin/bips/blob/master/bip-0433.mediawiki BIP 433]. The scriptPubKey is <code>OP_1 <0x4e73></code>, serialized as the bytes <code>0x51 0x02 0x4e 0x73</code>. On mainnet the corresponding [[Bech32m]] address is <code>bc1pfeessrawgf</code>. Spending requires an empty witness. Anyone able to broadcast a child that spends the output can attach fees. P2A names the output template. It is not the same as a keyed Lightning <code>option_anchors</code> output, and it is not the same as an [[Ephemeral_anchor\|ephemeral anchor]], which is a usage pattern that combines a P2A output with [[TRUC]] policy and ephemeral dust.

			== Template ==

	Because the program is a native witness output, BIP 141 requires a blank scriptSig, so the spending transaction's txid is stable against scriptSig malleation. Bitcoin Core treats a non-empty witness as nonstandard for this template, which keeps the wtxid stable against witness padding under standard relay. Consensus still accepts any witness. BIP 433 recommends combining P2A with TRUC to bound pinning by an oversized low-feerate child. Bitcoin Core 28.0 made P2A spends standard. Core 29.0 added ephemeral-dust policy for a zero-value P2A spent in the same package.		Because the program is a native witness output, BIP 141 requires a blank scriptSig, so the spending transaction's txid is stable against scriptSig malleation. Bitcoin Core treats a non-empty witness as nonstandard for this template, which keeps the wtxid stable against witness padding under standard relay. Consensus still accepts any witness. BIP 433 recommends combining P2A with TRUC to bound pinning by an oversized low-feerate child. Bitcoin Core 28.0 made P2A spends standard. Core 29.0 added ephemeral-dust policy for a zero-value P2A spent in the same package.

			The fixed mainnet address <code>bc1pfeessrawgf</code> is shared by all P2A outputs of that template. Block explorers therefore show many unrelated protocols paying to the same script. Wallet coin selection should treat P2A outputs as fee anchors rather than as ordinary user funds.

			== Use with TRUC ==

	P2A is intended as a shared, anyone-can-spend fee anchor for packages that need a stable txid and a place to attach fees without a key ceremony. Contracting protocols can create a zero-fee or low-fee parent that pays to P2A and then broadcast a TRUC child that spends the anchor at a competitive feerate. Because the witness is empty under policy, counterparties do not need to coordinate a signature just to attach fees. Keyed Lightning anchor outputs remain a separate template used inside many channel commitment designs.		P2A is intended as a shared, anyone-can-spend fee anchor for packages that need a stable txid and a place to attach fees without a key ceremony. Contracting protocols can create a zero-fee or low-fee parent that pays to P2A and then broadcast a TRUC child that spends the anchor at a competitive feerate. Because the witness is empty under policy, counterparties do not need to coordinate a signature just to attach fees. Keyed Lightning anchor outputs remain a separate template used inside many channel commitment designs.
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	Because anyone can spend a P2A output under policy, fee-bumping races are open. Counterparties may broadcast competing children. [[TRUC]] sibling eviction keeps only the more incentive-compatible child beside the parent. Without TRUC, keyed anchors or carve-out-era policies were used to reserve a bump path for each party.		Because anyone can spend a P2A output under policy, fee-bumping races are open. Counterparties may broadcast competing children. [[TRUC]] sibling eviction keeps only the more incentive-compatible child beside the parent. Without TRUC, keyed anchors or carve-out-era policies were used to reserve a bump path for each party.

	~~The fixed mainnet address <code>bc1pfeessrawgf</code> is shared by all~~ P2A ~~outputs of that template. Block explorers therefore show many unrelated protocols paying to~~ the same ~~script. Wallet coin selection should treat P2A outputs as fee anchors rather than as ordinary user funds~~.		Ephemeral-anchor packages are the usual contracting pattern: create the P2A output and spend it in the same unconfirmed [[TRUC]] child so the UTXO set never retains the anchor after confirmation.


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

NotATether: Expand See also links

2026-09-13T07:27:57Z

Expand See also links

← Older revision		Revision as of 07:27, 13 September 2026
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	* [[Ephemeral_anchor\|Ephemeral anchor]]		* [[Ephemeral_anchor\|Ephemeral anchor]]
			* [[Anchor output]]
	* [[TRUC]]		* [[TRUC]]
			* [[Package relay]]
	* [[Lightning Network]]		* [[Lightning Network]]
	* [[Segregated Witness]]		* [[Segregated Witness]]

NotATether: Add shared address and coin-selection note

2026-09-13T07:27:55Z

Add shared address and coin-selection note

← Older revision		Revision as of 07:27, 13 September 2026
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	Because anyone can spend a P2A output under policy, fee-bumping races are open. Counterparties may broadcast competing children. [[TRUC]] sibling eviction keeps only the more incentive-compatible child beside the parent. Without TRUC, keyed anchors or carve-out-era policies were used to reserve a bump path for each party.		Because anyone can spend a P2A output under policy, fee-bumping races are open. Counterparties may broadcast competing children. [[TRUC]] sibling eviction keeps only the more incentive-compatible child beside the parent. Without TRUC, keyed anchors or carve-out-era policies were used to reserve a bump path for each party.

			The fixed mainnet address <code>bc1pfeessrawgf</code> is shared by all P2A outputs of that template. Block explorers therefore show many unrelated protocols paying to the same script. Wallet coin selection should treat P2A outputs as fee anchors rather than as ordinary user funds.

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

NotATether: Add open fee-bump race and TRUC sibling eviction

2026-09-13T07:27:53Z

Add open fee-bump race and TRUC sibling eviction

← Older revision		Revision as of 07:27, 13 September 2026
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	P2A is intended as a shared, anyone-can-spend fee anchor for packages that need a stable txid and a place to attach fees without a key ceremony. Contracting protocols can create a zero-fee or low-fee parent that pays to P2A and then broadcast a TRUC child that spends the anchor at a competitive feerate. Because the witness is empty under policy, counterparties do not need to coordinate a signature just to attach fees. Keyed Lightning anchor outputs remain a separate template used inside many channel commitment designs.		P2A is intended as a shared, anyone-can-spend fee anchor for packages that need a stable txid and a place to attach fees without a key ceremony. Contracting protocols can create a zero-fee or low-fee parent that pays to P2A and then broadcast a TRUC child that spends the anchor at a competitive feerate. Because the witness is empty under policy, counterparties do not need to coordinate a signature just to attach fees. Keyed Lightning anchor outputs remain a separate template used inside many channel commitment designs.

			Because anyone can spend a P2A output under policy, fee-bumping races are open. Counterparties may broadcast competing children. [[TRUC]] sibling eviction keeps only the more incentive-compatible child beside the parent. Without TRUC, keyed anchors or carve-out-era policies were used to reserve a bump path for each party.

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

NotATether: Add package fee-bumping use and Lightning contrast

2026-09-12T21:11:18Z

Add package fee-bumping use and Lightning contrast

← Older revision		Revision as of 21:11, 12 September 2026
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	Because the program is a native witness output, BIP 141 requires a blank scriptSig, so the spending transaction's txid is stable against scriptSig malleation. Bitcoin Core treats a non-empty witness as nonstandard for this template, which keeps the wtxid stable against witness padding under standard relay. Consensus still accepts any witness. BIP 433 recommends combining P2A with TRUC to bound pinning by an oversized low-feerate child. Bitcoin Core 28.0 made P2A spends standard. Core 29.0 added ephemeral-dust policy for a zero-value P2A spent in the same package.		Because the program is a native witness output, BIP 141 requires a blank scriptSig, so the spending transaction's txid is stable against scriptSig malleation. Bitcoin Core treats a non-empty witness as nonstandard for this template, which keeps the wtxid stable against witness padding under standard relay. Consensus still accepts any witness. BIP 433 recommends combining P2A with TRUC to bound pinning by an oversized low-feerate child. Bitcoin Core 28.0 made P2A spends standard. Core 29.0 added ephemeral-dust policy for a zero-value P2A spent in the same package.

			P2A is intended as a shared, anyone-can-spend fee anchor for packages that need a stable txid and a place to attach fees without a key ceremony. Contracting protocols can create a zero-fee or low-fee parent that pays to P2A and then broadcast a TRUC child that spends the anchor at a competitive feerate. Because the witness is empty under policy, counterparties do not need to coordinate a signature just to attach fees. Keyed Lightning anchor outputs remain a separate template used inside many channel commitment designs.

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

NotATether: create Pay-to-anchor stub (BIP 433 P2A template)

2026-09-06T07:24:15Z

create Pay-to-anchor stub (BIP 433 P2A template)

New page

'''Pay-to-anchor''' (P2A) is a keyless native [[Segregated Witness]] version 1 output type described by [https://github.com/bitcoin/bips/blob/master/bip-0433.mediawiki BIP 433]. The scriptPubKey is <code>OP_1 <0x4e73></code>, serialized as the bytes <code>0x51 0x02 0x4e 0x73</code>. On mainnet the corresponding [[Bech32m]] address is <code>bc1pfeessrawgf</code>. Spending requires an empty witness. Anyone able to broadcast a child that spends the output can attach fees. P2A names the output template. It is not the same as a keyed Lightning <code>option_anchors</code> output, and it is not the same as an [[Ephemeral_anchor|ephemeral anchor]], which is a usage pattern that combines a P2A output with [[TRUC]] policy and ephemeral dust.

Because the program is a native witness output, BIP 141 requires a blank scriptSig, so the spending transaction's txid is stable against scriptSig malleation. Bitcoin Core treats a non-empty witness as nonstandard for this template, which keeps the wtxid stable against witness padding under standard relay. Consensus still accepts any witness. BIP 433 recommends combining P2A with TRUC to bound pinning by an oversized low-feerate child. Bitcoin Core 28.0 made P2A spends standard. Core 29.0 added ephemeral-dust policy for a zero-value P2A spent in the same package.

== See also ==

* [[Ephemeral_anchor|Ephemeral anchor]]
* [[TRUC]]
* [[Lightning Network]]
* [[Segregated Witness]]
* [[Bech32m]]

== External links ==

* [https://github.com/bitcoin/bips/blob/master/bip-0433.mediawiki BIP 433: Pay to Anchor (P2A)]
* [https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki BIP 431: Topology Restrictions for Pinning]
* [https://github.com/bitcoin/bitcoin/pull/30352 Bitcoin Core PR 30352]
* [https://bitcoinops.org/en/topics/ephemeral-anchors/ Bitcoin Optech: Ephemeral anchors]

[[Category:Technical]]