BatchNTTForward, BatchNTTInverse and BatchPolyMul were three copies of one
loop — snapshot the session, allocate operand tensors, run a kernel, sync, read
back, copy out, and on any failure at any step close what is open and do the
operation on the CPU instead. ~45 statements each, differing in how many
polynomials an element reads, which kernel runs, and what the CPU does instead.
Three copies of a resource lifecycle are three places to forget a Close, and a
fourth kernel would have been a fourth copy.
Now one offload plus one element, and three wrappers that name their three
differences. 101 lines go, no behaviour with them.
The floors are deliberately NOT unified: forward NTT reaches the device at 64
polynomials and ring degree 8192, the other two at 4 and any degree, and the
reasoning written on the forward path applies to all three. That reads as
drift, but changing a performance threshold needs a device to measure on and
this host has none, so the numbers are carried through as parameters and the
disagreement is stated where the next reader will see it.
Also drops the count == 0 guard, which count < minBatch already subsumes for
every floor; reverting it changed no test result, which is what redundant
means.
The lane that did this was killed before it could commit; the tree it left is
green and is preserved here rather than lost. Root package 51.5% at the start
of the day, 93.3% at its last checkpoint, 98.6% now, with cert, fhe, types and
cmd/plugin all passing.
Includes the fault-injection suite it was building when it stopped: a node that
cannot read its state does not start, and one that cannot enumerate its
registry does not either.
Not reviewed by me beyond build, vet, gofmt and the full suite under -count=1.
The lane's own report is owed and did not arrive, so its mutation count and its
verdict on the mpcvm/fhe duplication are unrecorded.
M-Chain is the MPC/threshold-custody VM that replaces off-chain signer
clusters for bridge custody. This makes it one.
vmID — the one-way door. factory.go declared a private `thresholdvm`
literal that matched nothing else in the stack, and node/Dockerfile
installed the plugin under that name's CB58 while genesis declares
constants.MPCVMID. The two never met, so M-Chain could not have started.
VMID is now the shared constant, and TestVMID_IsCanonicalAndStable pins
the CB58 (qCURact1n41Fco...) with the list of every declaration that must
move together if it ever changes before launch.
k vs t. types.Ceremony carried Threshold/Total as bare uint16s: Validate
read Threshold as the signer count (enforcing threshold*2 > total) while
the VM read it as the polynomial degree and passed it straight to
cmp.Keygen. The same field meant K in one file and t in another, and the
two differ by one — the same silent off-by-one that produces a 4-of-5
wallet from a config saying 3-of-5. Both now carry a quorum.Policy, and t
is only ever obtained by calling Degree(). The majority floor survives as
types.HasUniqueQuorum, defined once and enforced on every key record.
State. The VM kept its custody keys in a map persisted only on a clean
Shutdown, with the key share excluded from the wire entirely, and reset
lastAccepted to a recomputed genesis block on every Initialize — so a
restart discarded the chain and came back unable to sign. State is now
persisted at the moment each fact becomes true, split into a replicated
c/ keyspace (key registry, ceremony log, blocks, height index, root) and
a node-private n/ keyspace (this validator's shares), and Initialize
resumes the accepted tip.
Blocks verify. A block carries its post-state root and every operation's
artifact. Verify re-checks a signature against the group key already in
the registry — a proposer cannot fabricate one without forging ECDSA — and
recomputes the root, so two validators that would diverge cannot both
accept. Keygen operations carry a proof of possession by the new group key
over its own registration; a participant additionally cross-checks the
declared degree against its own share, so one honest participant rejects a
mis-declared key.
Ceremonies are leaderless. The id is derived from the task
(key, digest, sorted signers), so every validator converges on the same
ceremony with no announce round and no coordinator, and the committee is
the chain's own validator set rather than an operator roster.
Address derivation was SHA-256 where every EVM chain uses Keccak-256, so
the published custody address did not belong to the group key. Funds sent
there would have been unspendable.
Deletes the duplicate signing paths and the in-memory session machinery:
one way to generate a key, one way to sign.
Co-authored-by: Hanzo Dev <[email protected]>
Under LP-0130's canonical roster, chains/thresholdvm/ hosts the M-Chain
VM (MPC threshold signing). The package name "thresholdvm" was the last
piece of T-Chain nomenclature still shipping in code — legacy from the
pre-LP-134 shared-substrate design. Renamed to mpcvm/ so the package
name matches the M-Chain letter and LP-7100 spec.
- chains/thresholdvm/ → chains/mpcvm/ (dir + inner files + package decl)
- Sed-replace thresholdvm → mpcvm across .go / .md / .yml / .json / .sh
- Fee/settlement primitive references now say mpcvm
- LLM.md canonical chain roster (LP-0130) already points at mpcvm/
F-Chain runtime pieces (fhe/, protocol/tfhe_keygen/,
runtime/f_chain_adapter.go) stay under mpcvm/ for now — they consume
the same shared threshold primitives. A follow-up extract to
chains/fhevm/ can happen once F-Chain runtime graduates.
Co-authored-by: Hanzo Dev <[email protected]>
zeekay
