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bip-0360: added python reference example; test vector fixes#2202

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notmike-5:p2mr
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bip-0360: added python reference example; test vector fixes#2202
notmike-5 wants to merge 16 commits into
bitcoin:masterfrom
notmike-5:p2mr

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@notmike-5 notmike-5 commented Jun 26, 2026

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This PR adds a python reference example for construction of BIP-360 outputs and control blocks.

It updates the test vectors to remove "internalPubkey" key from vectors 7 and 8, and adds a new test for duplicate script leaves.

This PR also brings in fixes to #2102 and #2103 from @jbride

jbride and others added 4 commits June 25, 2026 19:59
This commit adds a python reference example for construction of BIP-360 outputs and control blocks.
This commit also updates the test vectors.

@murchandamus murchandamus left a comment

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Looks reasonable at first glance.

cc: @cryptoquick, @EthanHeilman, @Isabelfoxenduke for owner review/sign-off.

@murchandamus murchandamus added Proposed BIP modification PR by non-owner to update BIP content Pending acceptance This BIP modification requires sign-off by the champion of the BIP being modified labels Jun 26, 2026
This refactors `compute_control_block` to improve performance, and make
the function simpler to read (to me at least).

The previous version walked the entire script tree searching for the
first matching instance of the leaf node.

The new version expects the caller to pass in an explicit `path`
parameter, which tells us exactly where the leaf node lives, with
left/right steps encoded as bits in an integer. We walk down the
tree straight to that leaf node, and build the control block as we go.

This might not be the best DX for a real-world API or library, but this
is just reference code, so we can accept poor usage ergonomics if it makes
the code clearer and more explicit.
Comment thread bip-0360/ref-impl/python/p2mr.py Outdated
Comment thread bip-0360/ref-impl/python/p2mr.py
Comment on lines +184 to +185
# Bech32 encoding code is taken from sipa (BIP-0350), and has been tested against the test vectors therein:
# https://github.com/sipa/bech32/blob/master/ref/python/tests.py

@conduition conduition Jun 26, 2026

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Most of this code already exists in the BIPs repository, under the reference code of BIP352 (silent payments).

https://github.com/bitcoin/bips/blob/master/bip-0352/bech32m.py

@murchandamus What are your thoughts on the bech32m code duplication here? is it better to duplicate for the sake of compartmentalization, or should we update the existing code and reference it here?

Comment thread bip-0360/ref-impl/python/p2mr.py Outdated
Comment thread bip-0360/ref-impl/python/p2mr.py Outdated
Comment thread bip-0360/ref-impl/python/p2mr.py Outdated
Comment thread bip-0360/ref-impl/python/p2mr.py Outdated
Comment thread bip-0360/ref-impl/python/p2mr.py Outdated
test_vectors
});

static P2TR_USING_V2_WITNESS_VERSION_ERROR: &str = "p2tr_using_v2_witness_version_error";

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I think this should be renamed to "p2tr_using_v2_witness_version_error" to follow the test vector renaming.

Currently cargo test fails with:

  called `Option::unwrap()` on a `None` value

After renaming it passed.

@notmike-5 notmike-5 Jun 27, 2026

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The test is checking p2mr misuse and specifically presence of an internal pubkey. That said, I don't have strong feelings one way or the other. We might need to update this file to also reflect the new test vector @jbride.

Standardizes all P2MR-specific functions to use bytes uniformly for
input/output. Hex conversions are now confined to two boundaries:
reading `script` field out of ScriptTree input, and comparing against
hex-encoded test vector data in `run_single_test`.

bech32 functions and s2w are left unchanged.
Comment thread bip-0360/ref-impl/python/p2mr.py Outdated
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5 participants