tap-ldk

tap-ldk is an experimental Rust/LDK wallet demo for Taproot Assets. The goal is simple: show that a stablecoin-like asset can be issued, checked, sent, and received by an LDK-based wallet without running LND or tapd as a wallet sidecar.

This is demo software. It is not production-ready wallet infrastructure.

Status

Last updated: 2026-05-30

• Official BOLT Simple Taproot status: the pinned OpenAgentsInc rust-lightning fork implements the Bitcoin channel base from bolt-simple-taproot.md. That means final feature negotiation, required nonce/signature messages, MuSig2 signing and verification, P2TR funding and commitment outputs, cooperative close with RBF, reconnect nonce maps, BTC splice nonce maps, HTLC and second-level outputs, unilateral spend metadata, and BOLT vector replay are covered. This is not an upstream LDK release claim, and the BOLT does not cover the Taproot Assets proof layer below.
• The native wallet-to-wallet demo works: issue demo OPENUSD, exchange proofs, open one asset channel, pay, restart, close, export proofs, and recover the recorded asset state.
• The lnd/tapd/litd compatibility demo works for the first demo against integrated litd: litd funds an asset channel and pays native LDK; native LDK records the received balance; native LDK then pays the asset back to litd; both sides report the expected balance after settlement.
• The wallet code includes the core pieces needed for this proof of concept: asset proof checks, asset commitments, simple taproot channel support, asset payment metadata, restart-safe storage, close handling, and recovery records.
• Proof import is intentionally strict. The wallet rejects shallow or mismatched proofs before balance or channel state can change. Wallet balance/export checks now also distinguish confirmed, pending, stale, and reorged proof anchors at the bounded replay boundary.
• The first proof-engine hardening sequence is complete: #96 through #106 added typed proof-history replay, negative vectors, TLA+ proof-validation checks, Rust-native property/fuzz/Kani harnesses, close/recovery replay, anchor-state policy, a local proof-engine check wrapper, and a passing Google Cloud Build fast suite.
• The local proof-courier hardening sequence is complete: #107 through #110 added a typed bundle that moves proof bytes, optional TAPF bytes, proof-history IDs, anchor state, asset fields, and digests together. The wallet and CLI can import/export those bundles, and negative tests cover malformed transport, mismatched fields, bad digests, stale/reorged anchors, and proof-history mismatches.
• The first demo is complete. The closed issues #81, #57, #58, #59, #60, #61, #71, and #19 are the checks we keep running for live settlement, payments in both directions, observed balances, proof checks, simple taproot channels, and lnd/tapd/litd software compatibility.
• The typed chain/sweeper observation gate is now in the normal proof-engine wrapper. It validates bounded close, unilateral, HTLC, sweep, refusal, and restart observations through chain-watcher-lifecycle-smoke, while still refusing live watcher or production-ready claims.
• The live regtest callback bridge now exists in the extended proof-engine path. It binds the observation report to actual Bitcoin Core regtest height/block data and typed watcher/sweeper callback records. It is still not a live close or force-close claim because the close/sweep anchors remain bounded synthetic demo anchors.

Still not done:

• network proof courier/universe service;
• full production proof-history coverage beyond the current bounded replay surfaces;
• grouped assets and multi-asset channels;
• split/change proof replay;
• live chain watcher and reorg integration for real close/sweep transactions;
• live force-close and sweep recovery;
• live post-close proof and balance checks;
• live lnd/tapd/litd RFQ signature checks;
• concurrent splice/RBF asset-channel support.

LND, tapd, and litd are test peers only. They are not sidecars inside the tap-ldk wallet.

Development

Run the main checks from the repo root:

./scripts/proof-engine-check.sh
./scripts/gcloud-proof-engine-submit.sh fast
./scripts/onchain-lifecycle-smoke.sh
./scripts/chain-watcher-lifecycle-smoke.sh
./scripts/live-regtest-chain-watcher-lifecycle-smoke.sh
cargo fmt --check
CARGO_NET_GIT_FETCH_WITH_CLI=true cargo test --locked
./scripts/check-btc-simple-taproot-conformance.sh
./scripts/check-simple-taproot-cooperative-close.sh
./scripts/check-simple-taproot-splice-policy.sh
./scripts/rust-verification-check.sh
./scripts/path-a-native-demo.sh
./scripts/path-b-lightning-labs-demo.sh

Useful CLI entry points:

cargo run -p tap-ldk-cli -- --help
cargo run -p tap-ldk-cli -- first-demo-scope
cargo run -p tap-ldk-cli -- simple-taproot-negotiation-report
cargo run -p tap-ldk-cli -- wallet-init target/demo-wallet.json
cargo run -p tap-ldk-cli -- wallet-balances target/demo-wallet.json
cargo run -p tap-ldk-cli -- wallet-export-proof-bundle target/demo-wallet.json '<proof-id>' target/proof-bundle.json
cargo run -p tap-ldk-cli -- wallet-import-proof-bundle target/receiver-wallet.json target/proof-bundle.json
cargo run -p tap-ldk-cli -- onchain-lifecycle-smoke
cargo run -p tap-ldk-cli -- chain-watcher-lifecycle-smoke
cargo run -p tap-ldk-cli -- live-regtest-chain-watcher-lifecycle-smoke 100 101 1 '<best-block-hash>'

Docs

• Roadmap
• Architecture
• Invariants
• Public Demo Runbook
• Native Wallet-To-Wallet Demo
• lnd/tapd/litd Compatibility Demo
• Taproot Assets LDK Issue 71 Closure Audit
• lnd/tapd/litd Compatibility Closure Audit
• BOLT Simple-Taproot Production Compliance Audit
• Current Status And Production Readiness Audit
• Proof Courier Bundles
• On-Chain Lifecycle Readiness
• Chain-Watcher Lifecycle Readiness
• Negative Proof Vector Coverage
• Rust-Native Verification
• Proof Engine CI