448 - Taproot-native (Re)bindable Transactions
BIP: 448 source Layer: Consensus (soft fork) Title: Taproot-native (Re)bindable Transactions Authors: Gregory Sanders Antoine Poinsot Steven Roose Status: Draft Type: Specification Assigned: 2026-03-11 License: CC0-1.0 Abstract This document proposes deploying three new operations for Tapscript: BIP 446 OP_TEMPLATEHASH, BIP 348 OP_CHECKSIGFROMSTACK, and BIP 349 OP_INTERNALKEY. These minimal operations introduce modular functionalities which improve existing second layer protocols and make new ones possible through plausible interactivity requirements. Motivation The three proposed operations are simple, well-understood, and enable powerful new capabilities while minimizing the risk of surprising behavior or unintended applications. They improve existing, well-studied protocols and make promising new ones possible. OP_TEMPLATEHASH allows a Tapscript to commit to the exact transaction that must spend it. This capability is a common building block for...
127 - Simple Proof-of-Reserves Transactions
BIP: 127 source Layer: Applications Title: Simple Proof-of-Reserves Transactions Authors: Steven Roose Status: Draft Type: Specification Assigned: 2019-01-28 License: CC0-1.0 Table of ContentsAbstractCopyrightMotivationWhat this BIP is not doingSpecificationProof FormatProof File FormatPSBT (BIP 174) extensionCompatibilityImplementationsFootnotes Abstract This BIP describes a simple way to construct proof-of-reserves transactions. This proposal formalizes a standard format for constructing such proofs, easing their construction with existing wallet infrastructure and enabling general proof-verification software. It relies on existing standards such as regular Bitcoin transaction serialization/validation and the BIP 174 PSBT format. The proposal also includes the description of a PSBT extension for a better user experience. Copyright This BIP is licensed under the Creative Commons CC0 1.0 Universal license. Motivation From the very early days in the history of Bitcoi...
446 - OP_TEMPLATEHASH
BIP: 446 source Layer: Consensus (soft fork) Title: OP_TEMPLATEHASH Authors: Gregory Sanders Antoine Poinsot Steven Roose Status: Draft Type: Specification Assigned: 2026-02-06 License: CC0-1.0 Abstract This document proposes a new operation for Tapscript: OP_TEMPLATEHASH. It introduces the ability to push on the stack a hash of the transaction spending an output. Motivation OP_TEMPLATEHASH can be used to commit to the transaction spending an output1. This capability can replace the use of pre-signed transactions in second-layer protocols. By reducing interactivity it makes such protocols simpler, safer, and sometimes notably more efficient. For instance it can remove the need to share HTLC signatures in the Lightning Network protocol's commitment_signed message2, make receiving an Ark "VTXO" non-interactive, and reduces roundtrips in the implementation of LN-Symmetry. It is also a significant optimisation for Discreet Log Contracts. Specification ...
346 - OP_TXHASH
BIP: 346 source Layer: Consensus (soft fork) Title: OP_TXHASH Authors: Steven Roose Brandon Black Status: Draft Type: Specification Assigned: 2024-04-24 License: BSD-3-Clause Abstract This BIP proposes a new opcode OP_TXHASH, to be activated as a change to the semantics of OP_SUCCESS189 in tapscript contexts. This opcode provides a generalized method for introspecting certain details of the spending transaction, which enables non-interactive enforcement of certain properties of the transaction spending a certain UTXO. Together with an opcode like OP_CHECKSIGFROMSTACK, this opcode effectively provides a fully generalized signature hash construction, fully supporting all existing SIGHASH flags, the proposed sighash flags from BIP-118 (SIGHASH_ANYPREVOUT) and many other new signature hash combinations. The constructions specified in this BIP also open up the way for other potential updates; see Motivation section for more details. Specification OP_TXHASH OP_TXHAS...