Implemented operational boundary
The BFT collector now retains authenticated double-vote evidence instead of only returning an equivocation error. Both Ed25519 signatures must verify against an independently trusted historical committee. Chain, height, round, phase, voter and committee root must match; block-or-nil values must differ. A duplicate or an unauthenticated accusation never produces a proof or changes quorum power.
DoubleVoteEvidence uses the fixed 380-byte ALDV version-1 format: an 8-byte
tag/version followed by two canonical 186-byte votes. Values are ordered with
nil before non-nil and then by hash. Reversed pairs, duplicates, malformed tags,
truncation and trailing bytes are rejected. Decoding alone does not authenticate
the evidence. The proof ID commits both full votes; the offence ID commits the
shared slot independently of which pair proves three or more conflicting votes.
Collectors retain at most one proof per committee member across round changes.
Voting network nodes persist their first proof per registered member in
<data-dir>/equivocation/<validator-id>.bin. Files are created exclusively and
flushed before a successful observation is exposed. Unix directory entries are
also synced. The fixed reference profile has at most 32 members, so stored proof
payloads total at most 12,160 bytes. Repeated accusations cannot grow this store.
Observers currently do not collect gossip votes for evidence.
Restart reauthenticates recognized proof files against their historical committee. For genesis-v2 networks it sorts the bounded proof set by height and verifies one shared handoff stream from trusted genesis; it does not replay the entire stream separately for every proof. Corrupt/truncated files, identity mismatches and symlinked proof paths fail closed; they are not silently repaired. A write failure propagates as a local error and stops the normal daemon driving path. An interrupted first write may therefore require operator investigation. This outbox has no independent anti-rollback anchor; loss of a proof file cannot be detected as a consensus violation. Raw evidence itself remains portable and independently verifiable.
Operator commands
cli evidence-create <genesis> <validators> <vote-a> <vote-b> <output> [rpc-address]
authenticates two binary votes and writes a canonical proof without overwriting
an existing file. Version-1 full-genesis committees need no RPC access. For a
version-2 rotating committee, the optional address selects the node serving the
historical handoffs (the usual local RPC address is the default). The command
verifies at most 10,000 transitions under a shared 60-second deadline and saves
<output>.handoffs only after both votes authenticate against that height's committee.
An identity that has left the committee cannot create evidence for that height.
cli evidence-verify <genesis> <validators> <proof> verifies a saved proof without
modifying it. Rotating proofs require the matching <proof>.handoffs sidecar;
keep both files together. A bare rotating-node outbox proof needs the same verified
history before it can be used offline. Missing, truncated or foreign history is
rejected. Inputs are bounded. Supply independently trusted genesis and the complete
public-key registry. No private key is needed. Proof output is not an automatic
on-chain penalty.
Vote signatures in the existing protocol bind chain ID and committee root, not the genesis hash directly. Do not reuse chain IDs and identical voting contexts across deployments and assume that the CLI can distinguish those signatures.
Reference scoring
PotbTracker replays contiguous certified headers from a caller-supplied trusted
anchor. Every transition checks parent, height, committee, signatures and quorum
before atomically publishing counters. Callers must supply independently trusted
historical membership and separately verify execution/state transitions.
For each explicitly enrolled identity the tracker counts finalized heights of committee membership and certificate mentions. Membership age is not uptime. Certificate mentions are diagnostic only: a producer may publish a valid quorum subset that excludes an honest participant, so absence cannot justify punishment or a smaller score. No wall-clock duration, local latency or social endorsement feeds the score.
An explicit PotbPolicy defines epoch size, initial score, age increment and cap.
The integer-only reference formula is:
epochs = eligible_blocks / epoch_blocks
candidate_weight = min(maximum_weight, initial_weight + epochs * age_increment)
The implementation avoids intermediate overflow even at full-width u128 limits. A verified historical double vote yields candidate weight zero for that identity under this reference policy. Duplicate proofs cannot stack penalties; choosing the minimum offence ID makes accumulated observations order-independent. Re-entry, admission costs, identity splitting, ownership concentration and trust-graph policy are not solved by an age bonus or a per-identity cap.
These candidate scores are not active consensus weights. Local observations are not canonically finalized evidence. The reference daemon continues to use its genesis weights. Activating PoTB requires a versioned evidence-inclusion/state transition protocol, finalized parameter activation, a vetted VRF/sampler, safe weighted committee handoff, admission policy and independent review. Locally observing an offence must never unilaterally change a node's quorum threshold. No stake is deducted by this change. Proposal-equivocation evidence remains work.
Historical inclusion foundation
Document 42 specifies a bounded historical committee accumulator and portable offence bundle. Handoff verification authenticates this local history incrementally. The separate PoTB producer profile commits this frontier and implements canonical inclusion, active age weights, permanent exclusion and admission execution. Live activation adds daemon execution, authenticated inclusion gossip and operator submission. Admission policy for the closed network requires authorization by strictly more than two thirds of incumbent voting power.
Validation and claims
Tests cover forged signatures, mismatched contexts, canonical ordering, all proof truncations and single-byte mutations, bounded collector retention, atomic failed replay, certificate-subset neutrality, repeated/out-of-order offences, full-width arithmetic, real node persistence/restart and CLI proof verification. These tests establish the implemented invariants, not global superiority or a security proof for complete PoTB. Network throughput and finality latency still require published hardware/workload/fault profiles and independently reproducible runs.