nmc(P1b): wire AuxPow::check_proof chain-merkle leg (step 1) + KATs - #180
Merged
Conversation
Lands aux_merkle_root() in nmc::coin (header_chain.hpp): the merge-mining merkle-branch walk that AuxPow::check_proof() will consume for step-1 (chain-merkle-root, aux block hash -> merged-mining root) and step-3 (parent tx-merkle-root, coinbase txid -> parent block merkle root). Byte-faithful port of legacy libcoind/data.cpp check_merkle_link() -- the same SSOT btc/ltc use -- kept NMC-LOCAL per coin fence #4 (only core/* Hash + PackStream; no btc/ltc include). Per-level index bit selects LEFT vs RIGHT sibling, folded with SHA256d of the 64-byte concatenation; an index that does not fit branch.size() bits is rejected. check_proof() stays a P-DEFER stub: marker-scan, parent tx-merkle recompute and parent PoW are the next sub-slice, so NMC still MUST NOT block-validate off this leaf. Test: nmc_auxpow_merkle_test (gtest) pins the walk with INDEPENDENTLY derived expected roots (empty-branch identity, left/right sibling order, two-step per-level fold, index-overflow guard). Registered in both test/CMakeLists.txt and the build.yml --target allowlist. 5/5 PASS, exit 0.
check_proof() reconstructs the merged-mining merkle root from the aux block hash through chain_merkle_branch/chain_merkle_index via the P1a aux_merkle_root() primitive. New INCOMPLETE CheckResult state: a structurally-consistent chain-merkle walk returns INCOMPLETE (never VALID) because step 2 (MM-marker commitment + chain_id/slot binding), step 3 (parent-coinbase tx-merkle leg) and step 4 (parent PoW) are not built yet -- NMC still MUST NOT block-validate off this leaf. Malformed slot indices (negative, or wider than branch depth) return INVALID. 4 KATs pin the INCOMPLETE-vs-INVALID boundary so the leg cannot silently regress into asserting VALID. nmc_coin linked into the test (AuxPow ctor pulls MutableTransaction). 9/9 PASS. NMC-local, btc tree READ-ONLY.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
P1b — AuxPow::check_proof chain-merkle leg (step 1)
Builds on P1a (PR #178, aux_merkle_root primitive). Wires step 1 of the 4-step AuxPow verification: reconstruct the merged-mining merkle root from the aux (NMC) block hash through chain_merkle_branch/chain_merkle_index via aux_merkle_root().
Safety
New CheckResult::INCOMPLETE state. A structurally-consistent chain-merkle walk returns INCOMPLETE, never VALID — steps 2 (MM-marker commitment + chain_id/slot binding), 3 (parent-coinbase tx-merkle leg, needs witness-stripped BTC coinbase txid), 4 (parent PoW vs target) are NOT built. NMC still MUST NOT block-validate off this leaf. Malformed slot indices (negative / wider than branch depth) return INVALID.
Tests
4 new KATs (NmcAuxCheckProof) pin the INCOMPLETE-vs-INVALID boundary. 9/9 PASS (5 P1a + 4 P1b), build green. Test target name unchanged → CI --target allowlist needs no edit. nmc_coin linked (AuxPow ctor pulls MutableTransaction).
Fence
NMC-local only; btc tree consumed READ-ONLY. Merge gated (I do not self-merge).
Next (P1c)
step 3 parent-coinbase tx-merkle leg — requires pinning the witness-stripped BTC coinbase txid serialization params (separate slice + KAT).