Files
consensus/protocol/quasar/pulsar/errors.go
T
zooqueen f5ab5e2578 quasar: Pulsar threshold ML-DSA as a Quasar certificate profile
Add protocol/quasar/pulsar -- the consensus-side adapter that wires the
luxfi/pulsar threshold ML-DSA primitives into Quasar as a cert profile.
Consensus consumes Pulsar; Pulsar never consumes consensus.

Decomplected ownership (the load-bearing boundary):

  Consensus owns ORCHESTRATION: validator-set membership, committee
  sampling, session binding, canonical nonce selection, QC aggregation,
  signer bitmap, ConsensusCert assembly, retries, fallback, slashing
  inputs.

  Pulsar owns CRYPTO: the two-round shape (Round1 binds the nonce,
  Round2 emits a proof-carrying z partial), z aggregation mod q, the
  public hint recovery (FindHint over w' = A*z - c*t1*2^d), and the
  final FIPS 204 ML-DSA signature.

PulsarRoundSigner implements luxfi/pulsar's RoundSigner interface:

  Round1   selects the canonical NonceCert via pulsar.CanonicalNonceIndex
           over the session and refuses any non-canonical nonce
           (anti-grind: a coordinator cannot pick w1, hence the
           challenge, by choosing among boundary-clear certs after
           seeing the message).
  Round2   emits one signer's z Partial; pulsar.VerifyZPartial enforces
           the public bindings + the registered ZK correctness check.
  Finalize selects the canonical signer subset
           (pulsar.CanonicalSignerSet), aggregates z
           (pulsar.MergeAggregates), and assembles the two-certificate
           ConsensusCert accountability artifact (signer bitmap +
           transcript root).

The final FIPS 204 signature byte production is secret-bearing (needs
the module matrix A, t1, the challenge, and the per-coefficient hint),
all package-private to luxfi/pulsar, so it stays there: Finalize
delegates to a pluggable SignatureCore. The core is fail-closed until
luxfi/pulsar ships a reviewed Boundary-Cleared / Carry-Elimination
signer (pulsar.ProductionBCCSigningReady); until then Finalize returns
a structurally-complete ConsensusCert with an EMPTY Signature and
ErrProfileNotReady, and the orchestrator falls back to Corona. No
secret residual is ever opened on this path.

Session binding (session.go): the 32-byte session id is a
domain-separated cSHAKE256 over chain_id, epoch, height, round,
block_hash, validator_set_root, joint_pk_id, dkg_transcript_root,
committee_id, signer_set_root, nonce_pool_root, protocol_version --
every field fixed-width for canonical (non-grindable) encoding. Validate
refuses a session with an all-zero security-relevant root (cross-round
replay guard).

NonceCert generation is a BACKGROUND validator subprotocol filling a
NonceCertPool (pool.go) -- never inline on the block hot path. An empty
pool yields ErrNonceCertPoolEmpty (fall back to Corona), never an inline
nonce.

The profile registers by the package convention (like wave_signer.go's
RoundSigner): a self-contained pulsar.RoundSigner whose ConsensusCert
Signature bytes feed the existing QuasarCert.Pulsar slot and verify via
the polaris.go verifyPulsarLeg / pulsarwire.VerifyBytes path already
wired. No change to polaris.go (cert assembly is a separate concern).

go.mod: replace github.com/luxfi/pulsar => ../luxfi/pulsar. The
RoundSigner / NonceCert / CertProfile API lands on the
fix/threshold-mldsa-hint-leak branch and is not in any published tag
(cached v1.1.1 predates it). Remove the replace once a tag carrying the
API ships.

Tests (protocol/quasar/pulsar, all green): contract implementation,
Round1->Round2->Finalize fail-closed fallback, stub-core success wiring,
empty-pool fallback, non-canonical-nonce rejection, full session-id
field binding, session validation. go build ./... green; existing
protocol/quasar suite unchanged and green.
2026-06-21 02:00:25 -07:00

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2.0 KiB
Go

// Copyright (C) 2025-2026, Lux Industries Inc. All rights reserved.
// See the file LICENSE for licensing terms.
// errors.go -- typed errors for the Pulsar cert profile. These are the
// fallback / retry signals the Quasar orchestrator matches against to decide
// whether to fall back to Corona, retry with a fresh nonce, or slash.
package pulsar
import "errors"
var (
// ErrNonceCertPoolEmpty signals the background NonceCert pool is empty.
// The orchestrator MUST fall back to Corona (or retry once the pool
// refills); the hot path NEVER generates a nonce inline.
ErrNonceCertPoolEmpty = errors.New("quasar/pulsar: NonceCert pool empty; fall back to Corona")
// ErrProfileNotReady signals the secret-bearing FIPS 204 signature-assembly
// core is not registered (pulsar.ProductionBCCSigningReady() is false: the
// BCC/CEF ZK proofs are fail-closed). Finalize still returns a
// structurally-complete ConsensusCert with an EMPTY Signature; the
// orchestrator falls back to Corona.
ErrProfileNotReady = errors.New("quasar/pulsar: BCC signing core not registered; fall back to Corona")
// ErrSessionFieldUnset rejects a PulsarSession with an all-zero
// security-relevant root (unbound field). Signing under it would allow
// cross-round replay.
ErrSessionFieldUnset = errors.New("quasar/pulsar: session has an unset security-relevant field")
// ErrNonCanonicalNonce signals the supplied nonce id is not the canonical
// pool selection for this session. Every signer recomputes the canonical
// index and refuses a non-canonical nonce (anti-grind).
ErrNonCanonicalNonce = errors.New("quasar/pulsar: non-canonical nonce for session")
// ErrInsufficientShares signals fewer collected shares than the threshold.
ErrInsufficientShares = errors.New("quasar/pulsar: fewer shares than threshold")
// ErrNoNonceCert signals Round2/Finalize were called without a bound
// Round1 (no NonceCert).
ErrNoNonceCert = errors.New("quasar/pulsar: no bound NonceCert (call Round1 first)")
)