Sign-to-contract commitments standards

README.md

@@ -166,3 +166,4 @@ Game theory                | Game-theoretical setups for trustless protocols
 [81]: lnpbp-0081.md
 [85]: https://github.com/LNP-BP/client_side_validation/blob/master/strict_encoding/src/bitcoin.rs
 [86]: https://github.com/internet2-org/aluvm-spec
+[92]: lnpbp-0092.md

lnpbp-0092.md

@@ -0,0 +1,87 @@
+```
+LNPBP: 0092
+Vertical: Bitcoin protocol
+Title: Deterministic embedding of cryptographic commitments into bitcoin  
+       transaction input
+Author: Dr Maxim Orlovsky <[email protected]>
+Comments-URI: https://github.com/LNP-BP/lnpbps/pulls/<____>
+Status: Draft
+Type: Standards Track
+Created: 2021-11-15
+Finalized: not yet
+License: CC0-1.0
+```
+
+- [Abstract](#abstract)
+- [Background](#background)
+- [Motivation](#motivation)
+- [Design](#design)
+- [Specification](#specification)
+- [Compatibility](#compatibility)
+- [Rationale](#rationale)
+- [Reference implementation](#reference-implementation)
+- [Acknowledgements](#acknowledgements)
+- [References](#references)
+- [Copyright](#copyright)
+- [Test vectors](#test-vectors)
+
+
+## Abstract
+
+The proposal standardizes sign-to-contract commitmnets in bitcoin transaction
+inputs, proposing a robust and efficient scheme. It defines commitment and
+verification protocol, scope of applicable conditions when the commitment
+can be created and provides specific of client-side data structures used for
+keeping and validating commitment proofs.
+
+
+## Background
+
+
+## Motivation
+
+
+## Design
+
+Sing-to-contract commitments are embedded into transaction outputs depending
+on the type of the spent `scriptPubkey` and fields in the spending input.
+For always-single-public key types (P2PK, P2PKH, P2WPKH, P2TR key path spending,
+P2WPKH-in-P2SH) the only signature present in the `sigScript` or `witness`
+will contain the commitment. For script-based types (bare scripts, native P2SH, 
+P2WSH-in-P2SH, P2WSH and P2TR script path spendings), which may have from
+zero to any number of signatures a more elaborated scheme is used, where
+sign-to-contract commitment is embedded into any single signature, but the
+verification of the commitment is made against the sum of all signature
+nonces. Commitment procedure in this case also requires provable tweaking
+of other signature nonces with their own tagged hashes. 
+
+The commitment procedure results in creation of additional data structure,
+*extra-transaction commitment proof*, which must be kept on the client-side
+and is required for the commitment validation procedure.
+
+This commitment scheme does not support script spendings when the tx input
+contains no signatures, as well as P2TR script path spendings containing either
+Annex or using non-BIP-342 (TapSCript) scripting. In this cases commiter shell
+use other commitment schemes (like LNPBP-2) ensuring proper signalling like
+it is done in LNPBP-10 scheme.
+
+
+## Specification
+
+
+## Compatibility
+
+
+## Rationale
+
+## Reference implementation
+
+## Acknowledgements
+
+## References
+
+## Copyright
+
+This document is licensed under the Creative Commons CC0 1.0 Universal license.
+
+## Test vectors