CRITICAL
- PsbtSignatureVerifier: independently verifies every key-path signature in a
PSBT (BIP-340 sig over the BIP-341 sighash, against the tweaked output key).
- OnchainZapSender now rejects a signer that returns a different transaction
than it was asked to sign (byte-compares the unsigned tx) and verifies all
signatures before broadcasting — closes a substitution attack where a
malicious/buggy external signer could redirect funds.
HIGH — break test circularity
- Pin the full BIP-341 keyPathSpending input-0 witness: signing the vector
sighash with the vector tweaked key reproduces the vector signature
byte-for-byte (also pins BIP-340 nonce determinism).
- Pin TaprootAddress.fromPubKey + SegwitAddress.encodeP2TR against all seven
BIP-341 wallet-test-vector P2TR mainnet addresses.
- EsploraBackendTest: JSON-parsing coverage for /tx, /address/{}/utxo, the
mempool.space and blockstream fee formats, and schema-fallback.
MEDIUM
- OnchainZapBuilder filters to confirmed UTXOs by default (allowUnconfirmed
opt-in) and signals BIP-125 RBF (nSequence 0xFFFFFFFD).
- CachingOnchainBackend: TTL-caching decorator (confirmed tx forever,
unconfirmed/tip/fees short TTL) so a feed of onchain zaps doesn't fan out
into one HTTP request per event. Wired in AppModules.
- OnchainZapVerifier computes real confirmation depth from the chain tip and
asserts the backend echoed the requested txid.
- EsploraBackend falls back to the standard Esplora /fee-estimates endpoint
(blockstream.info) when /v1/fees/recommended 404s.
LOW
- BitcoinTransaction.parse caps input/output/witness-item counts to stop a
hostile varint from triggering a giant pre-allocation.
- OnchainZapEventTest: asserts kind:8333 on-the-wire tag structure against the
NIP-BC spec.
- alt tag now includes the amount ("Onchain zap: N sats"), matching the spec
example.
All quartz / commons / androidHostTest suites pass; amethyst compiles.
Claude
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