bip-0375: fix P2WPKH scriptPubKeys and signatures in test vectors #2316

pull fametrano wants to merge 1 commits into bitcoin:master from fametrano:bip375-p2wpkh-vectors changing 1 files +122 −122

fametrano commented at 6:39 PM on September 29, 2026: contributor

The P2WPKH inputs in BIP-375's test vectors cannot be spent by the keys they carry, and none of the 42 signatures in the vectors verifies. Each P2WPKH program is SHA256(pubkey)[:20] instead of HASH160(pubkey), and the reference validator does not check signatures, so no test catches it.

This PR repairs the file in place. Each P2WPKH program becomes HASH160(pubkey). The signatures are re-made with RFC 6979 and low S, under BIP 143 for P2WPKH and P2SH-P2WPKH and under the legacy sighash for P2PKH and the bare input. The SIGHASH_NONE vector now has a SIGHASH_NONE signature, as BIP 174 requires. The two signatures with no defined sighash, on the segwit v2 input and in the vector missing PSBT_OUT_SCRIPT, are removed; both vectors still fail for the same reason. The other 40 signatures now verify, and the runner's -vv output is unchanged: 43 passed. I did not regenerate the file, because that would also change unrelated values such as the prevout txids.

#2317, which depends on this PR, makes the test runner check these signatures: on master's vectors it reports 39 of 43 failing, on this PR's none. #2256 and #2207 edit some of the same vectors, and their P2WPKH inputs have the same defect. Whichever of this PR and #2256 lands second needs a rebase and the same repair.

Made with my usual tools: a computer, the Internet and an LLM. The mistakes, as usual, are all mine.

bip-0375: fix P2WPKH scriptPubKeys and signatures in test vectors

The P2WPKH inputs of the test vectors spend a witness program equal to
SHA256(pubkey)[:20] instead of HASH160(pubkey), so the key each input
carries cannot spend it. None of the stored ECDSA signatures verifies
against the transaction its PSBT describes, whatever the input type. The
reference validator does not check signatures, so no test fails.

Set every P2WPKH witness program to HASH160 of the input's public key,
in PSBT_IN_WITNESS_UTXO and in the supplementary witness_utxo and
prevout_scriptpubkey. Re-sign the PSBT_IN_PARTIAL_SIG signatures
deterministically (RFC 6979, low S): BIP 143 for P2WPKH and P2SH-P2WPKH,
the legacy signature hash for P2PKH and for the bare OP_2 input. Where
an input sets PSBT_IN_SIGHASH_TYPE, its signature uses that type, as BIP
174 requires.

Two vectors carried a signature with no defined signature hash: one on
a segwit v2 input, one in the vector whose output lacks PSBT_OUT_SCRIPT.
Remove both signatures, and mark the segwit v2 input as not signed in
the supplementary material. Both vectors still fail for their stated
reason.

Inside the PSBTs only PSBT_IN_WITNESS_UTXO and PSBT_IN_PARTIAL_SIG
change, and the test runner's result for every vector is unchanged.

d4d3e08e38

fametrano force-pushed on Sep 29, 2026

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fametrano

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#2207 BIP-375: correct labeled test vectors to include labeled-spend key in PSBT_OUT_SP_V0_INFO #2256 bip-0375: assign k in output index order, fix labeled test vectors #2317 bip-0375: check test vector signatures in the test runner