Verification Coverage Report

This document provides an overview of the formal verification, model checking, and conformance testing infrastructure in Aura.

Verification Boundary Statement

Aura keeps consensus and CRDT domain proof ownership in Quint models and Lean theorems. Telltale parity lanes validate runtime conformance behavior from replay artifacts. Telltale parity success does not count as new domain theorem coverage. See Formal Verification Reference for the assurance classification and limits.

Summary Metrics

Metric	Count
Quint Specifications	42
Quint Invariants	191
Quint Temporal Properties	11
Quint Type Definitions	362
Lean Source Files	38
Lean Theorems	118
Conformance Fixtures	4
ITF Trace Harnesses	9
Testkit Tests	118
Bridge Modules	4
CI Verification Gates	11
Telltale Parity Modules	1
Bridge Pipeline Fixtures	3

Verification Layers

Layer 1: Quint Specifications

Formal protocol specifications in verification/quint/ organized by subsystem.

Subsystem	Files	Contents
Root	11	core, authorization, recovery, invitation, interaction, leakage, sbb, time_system, transport, epochs, cli_recovery_demo
consensus/	4	core, liveness, adversary, frost
journal/	3	core, counter, anti_entropy
keys/	3	dkg, dkd, resharing
sessions/	4	core, choreography, groups, locking
amp/	1	channel
liveness/	3	connectivity, timing, properties
harness/	9	amp_channel, counter, dkg, flows, groups, locking, recovery, resharing, semantic_observation_smoke
tui/	4	demo_recovery, flows, signals, state

Harness modules generate ITF traces on demand via just quint-generate-traces. Traces are not checked into the repository. CI runs just ci-conformance-itf to generate traces and replay them through Rust handlers.

Key Specifications

Specification	Purpose	Key Properties
`consensus/core.qnt`	Fast-path consensus protocol	UniqueCommitPerInstance, CommitRequiresThreshold, EquivocatorsExcluded
`consensus/liveness.qnt`	Progress guarantees	ProgressUnderSynchrony, RetryBound, CommitRequiresHonestParticipation
`consensus/adversary.qnt`	Byzantine tolerance	ByzantineThreshold, EquivocationDetected, HonestMajorityCanCommit
`consensus/frost.qnt`	Threshold signatures	Share aggregation, commitment validation
`journal/core.qnt`	CRDT journal semantics	NonceUnique, FactsOrdered, NonceMergeCommutative, LamportMonotonic
`journal/anti_entropy.qnt`	Sync protocol	FactsMonotonic, EventualConvergence, VectorClockConsistent
`authorization.qnt`	Guard chain security	NoCapabilityWidening, ChargeBeforeSend
`time_system.qnt`	Timestamp ordering	TimeStamp domain semantics and comparison

Layer 2: Rust Integration

Files implementing Quint-Rust correspondence and model-based testing.

Core Integration (`aura-core`)

effects/quint.rs - QuintMappable trait for bidirectional type mapping
effects/mod.rs - Effect trait definitions with Quint correspondence

Quint Crate (`aura-quint`)

runner.rs - QuintRunner with property caching and verification statistics
properties.rs - PropertySpec, PropertySuite, and property categorization
evaluator.rs - QuintEvaluator subprocess wrapper for Quint CLI
handler.rs - Effect handler integration

Telltale Bridge (`aura-quint`)

Cross-validation modules for Lean↔Quint correspondence:

Module	Purpose
`bridge_export.rs`	Export Quint state to Lean-readable format
`bridge_import.rs`	Import Lean outputs back to Quint structures
`bridge_format.rs`	Shared serialization format definitions
`bridge_validate.rs`	Cross-validation assertions and checks

Simulator Integration (`aura-simulator/src/quint/`)

17 modules implementing generative simulation:

Module	Purpose
`action_registry.rs`	Maps Quint action names to Rust handlers
`state_mapper.rs`	Bidirectional state conversion (Rust <-> Quint JSON)
`generative_simulator.rs`	Orchestrates ITF trace replay with property checking
`itf_loader.rs`	Parses ITF traces from Quint model checking
`itf_fuzzer.rs`	Model-based fuzzing with coverage analysis
`trace_converter.rs`	Converts between trace formats
`simulation_evaluator.rs`	Evaluates properties during simulation
`properties.rs`	Property extraction and classification
`domain_handlers.rs`	Domain-specific action handlers
`amp_channel_handlers.rs`	AMP reliable channel handlers
`byzantine_mapper.rs`	Byzantine fault strategy mapping
`chaos_generator.rs`	Chaos/fault scenario generation
`aura_state_extractors.rs`	Aura-specific state extraction
`cli_runner.rs`	CLI integration for Quint verification
`ast_parser.rs`	Quint AST parsing for analysis
`mod.rs`	Module exports and re-exports
`types.rs`	Shared type definitions

Differential Verification (`aura-simulator`)

differential_tester.rs - Cross-implementation parity testing between Quint models and Rust handlers
telltale_parity.rs - Telltale-backed parity boundary, canonical surface mapping, and report artifact generation

Consensus Verification (`aura-consensus`)

core/verification/mod.rs - Verification module facade
core/verification/quint_mapping.rs - Consensus type mappings

Layer 3: Lean Proofs

Lean 4 mathematical proofs in verification/lean/ providing formal guarantees.

Type Modules (10 files)

Module	Content
`Types/ByteArray32.lean`	32-byte hash representation (6 theorems)
`Types/OrderTime.lean`	Opaque ordering tokens (4 theorems)
`Types/TimeStamp.lean`	4-variant time enum
`Types/FactContent.lean`	Structured fact types
`Types/ProtocolFacts.lean`	Protocol-specific fact types
`Types/AttestedOp.lean`	Attested operation types
`Types/TreeOp.lean`	Tree operation types
`Types/Namespace.lean`	Authority/Context namespaces
`Types/Identifiers.lean`	Identifier types
`Types.lean`	Type module aggregation

Domain Modules (9 files)

Module	Purpose
`Domain/Consensus/Types.lean`	Consensus message types (8 definitions)
`Domain/Consensus/Frost.lean`	FROST signature types
`Domain/Journal/Types.lean`	Fact and Journal structures
`Domain/Journal/Operations.lean`	merge, reduce, factsEquiv (1 theorem)
`Domain/FlowBudget.lean`	Budget types and charging
`Domain/GuardChain.lean`	Guard types and evaluation
`Domain/TimeSystem.lean`	Timestamp comparison
`Domain/KeyDerivation.lean`	Key derivation types
`Domain/ContextIsolation.lean`	Context isolation model

Proof Modules (14 files, 118 theorems)

Consensus Proofs

Module	Theorems	Content
`Proofs/Consensus/Agreement.lean`	3	No two honest parties commit different values
`Proofs/Consensus/Validity.lean`	7	Only valid proposals can be committed
`Proofs/Consensus/Equivocation.lean`	5	Detection soundness and completeness
`Proofs/Consensus/Evidence.lean`	8	Evidence CRDT semilattice properties
`Proofs/Consensus/Frost.lean`	12	FROST share aggregation safety
`Proofs/Consensus/Liveness.lean`	3	Progress under timing assumptions (axioms)
`Proofs/Consensus/Adversary.lean`	7	Byzantine model bounds
`Proofs/Consensus/Summary.lean`	-	Master consensus claims bundle

Infrastructure Proofs

Module	Theorems	Content
`Proofs/Journal.lean`	14	CRDT semilattice (commutativity, associativity, idempotence)
`Proofs/FlowBudget.lean`	5	Charging correctness
`Proofs/GuardChain.lean`	7	Guard evaluation determinism
`Proofs/TimeSystem.lean`	8	Timestamp ordering properties
`Proofs/KeyDerivation.lean`	3	PRF isolation proofs
`Proofs/ContextIsolation.lean`	16	Context separation and bridge authorization

Entry Points (4 files)

Aura.lean - Top-level documentation
Aura/Proofs.lean - Main reviewer entry with all Claims bundles
Aura/Assumptions.lean - Cryptographic axioms (FROST unforgeability, hash collision resistance, PRF security)
Aura/Runner.lean - CLI for differential testing

Layer 4: Conformance Testing

Deterministic parity validation infrastructure in aura-testkit.

Conformance Fixtures

Fixture	Purpose
`consensus.json`	Consensus protocol conformance
`sync.json`	Synchronization protocol conformance
`recovery.json`	Guardian recovery conformance
`invitation.json`	Invitation protocol conformance

Conformance Modules

Module	Purpose
`conformance.rs`	Artifact loading, replay, and verification
`conformance_diff.rs`	Law-aware comparison with envelope classifications

Effect Envelope Classifications

Class	Effect Kinds	Comparison Rule
`strict`	handle_recv, handle_choose, handle_acquire, handle_release	Byte-exact match required
`commutative`	send_decision, invoke_step	Order-insensitive under normalization
`algebraic`	topology_event	Reduced via domain-normal form

Verified Invariants

Consensus Invariants

Invariant	Location
`InvariantUniqueCommitPerInstance`	consensus/core.qnt
`InvariantCommitRequiresThreshold`	consensus/core.qnt
`InvariantCommittedHasCommitFact`	consensus/core.qnt
`InvariantEquivocatorsExcluded`	consensus/core.qnt
`InvariantProposalsFromWitnesses`	consensus/core.qnt
`InvariantProgressUnderSynchrony`	consensus/liveness.qnt
`InvariantRetryBound`	consensus/liveness.qnt
`InvariantCommitRequiresHonestParticipation`	consensus/liveness.qnt
`InvariantQuorumPossible`	consensus/liveness.qnt
`InvariantByzantineThreshold`	consensus/adversary.qnt
`InvariantEquivocationDetected`	consensus/adversary.qnt
`InvariantCompromisedNoncesExcluded`	consensus/adversary.qnt
`InvariantHonestMajorityCanCommit`	consensus/adversary.qnt

Journal Invariants

Invariant	Location
`InvariantNonceUnique`	journal/core.qnt
`InvariantFactsOrdered`	journal/core.qnt
`InvariantFactsMatchNamespace`	journal/core.qnt
`InvariantLifecycleCompletedImpliesStable`	journal/core.qnt
`InvariantNonceMergeCommutative`	journal/core.qnt
`InvariantLamportMonotonic`	journal/core.qnt
`InvariantReduceDeterministic`	journal/core.qnt
`InvariantPhaseRegistered`	journal/counter.qnt
`InvariantCountersRegistered`	journal/counter.qnt
`InvariantLifecycleStatusDefined`	journal/counter.qnt
`InvariantOutcomeWhenCompleted`	journal/counter.qnt
`InvariantFactsMonotonic`	journal/anti_entropy.qnt
`InvariantFactsSubsetOfGlobal`	journal/anti_entropy.qnt
`InvariantVectorClockConsistent`	journal/anti_entropy.qnt
`InvariantEventualConvergence`	journal/anti_entropy.qnt
`InvariantDeltasFromSource`	journal/anti_entropy.qnt
`InvariantCompletedSessionsConverged`	journal/anti_entropy.qnt

Temporal Properties

Property	Location
`livenessEventualCommit`	consensus/core.qnt
`safetyImmutableCommit`	consensus/core.qnt
`authorizationSoundness`	authorization.qnt
`budgetMonotonicity`	authorization.qnt
`flowBudgetFairness`	authorization.qnt
`canAlwaysExit`	tui/state.qnt
`modalEventuallyCloses`	tui/state.qnt
`insertModeEventuallyExits`	tui/state.qnt
`InvariantLeakageBounded`	leakage.qnt
`InvariantObserverHierarchyMaintained`	leakage.qnt
`InvariantBudgetsPositive`	leakage.qnt

Contract Coverage Mapping

This section maps the contract clauses in Privacy and Information Flow Contract and Distributed Systems Contract to the current verification and assurance evidence.

Coverage status uses three classes:

Verified: directly covered by Quint invariants, Lean proofs, or both
Conformance-backed: covered by replay, parity, or deterministic conformance lanes rather than domain theorem proofs
Specified only: documented as a contract requirement, but not yet directly mapped to a proof or conformance artifact in this report

Privacy and Information Flow Contract Coverage

Contract Area	Status	Evidence
Context-specific identity separation	`Verified`	`Aura.Proofs.KeyDerivation`, `Aura.Proofs.ContextIsolation`
Budgeted send invariant	`Verified`	`authorization.qnt`, `transport.qnt`, `Aura.Proofs.FlowBudget`, `Aura.Proofs.GuardChain`
Epoch-scoped receipt validity	`Verified`	`epochs.qnt`
Observer-budgeted metadata leakage	`Verified`	`leakage.qnt`
Cross-context isolation	`Verified`	`Aura.Proofs.ContextIsolation`, `transport.qnt`
Physical vs logical time privacy boundary	`Verified`	`time_system.qnt`, `Aura.Proofs.TimeSystem`
Error-channel privacy boundary	`Specified only`	No direct proof or conformance mapping recorded here
Retrieval not identity-addressed	`Conformance-backed`	`crates/aura-simulator/tests/adaptive_privacy_phase_six.rs`, selector-based `Hold` retrieval scenarios
Custody remains opaque and non-authoritative	`Conformance-backed`	`crates/aura-simulator/tests/adaptive_privacy_phase_six.rs`, `Hold` custody and cache-replica validation
Accountability evidence verified before local consequences	`Conformance-backed`	`crates/aura-simulator/tests/adaptive_privacy_phase_six.rs`, reply-block accountability control-plane lanes
External observer protection level varies by deployment mode	`Specified only`	No direct proof or conformance mapping recorded here

Distributed Systems Contract Coverage

Contract Area	Status	Evidence
Journal CRDT laws	`Verified`	`journal/core.qnt`, `Aura.Proofs.Journal`
Consensus agreement and validity	`Verified`	`consensus/core.qnt`, `Aura.Proofs.Consensus.Agreement`, `Aura.Proofs.Consensus.Validity`
Fault-bound consensus safety assumptions	`Verified`	`consensus/adversary.qnt`, `Aura.Proofs.Consensus.Adversary`
Evidence CRDT laws	`Verified`	`Aura.Proofs.Consensus.Evidence`
Equivocation detection	`Verified`	`consensus/adversary.qnt`, `Aura.Proofs.Consensus.Equivocation`
FROST threshold safety	`Verified`	`consensus/frost.qnt`, `Aura.Proofs.Consensus.Frost`
Context isolation	`Verified`	`transport.qnt`, `Aura.Proofs.ContextIsolation`
Anti-entropy convergence	`Verified`	`journal/anti_entropy.qnt`
Fast-path and fallback liveness under assumptions	`Verified`	`consensus/liveness.qnt`, `Aura.Proofs.Consensus.Liveness`
Invitation lifecycle safety	`Verified`	`invitation.qnt`
Cross-protocol deadlock freedom	`Verified`	`interaction.qnt`
Operation-scoped and journal consistency model	`Verified`	`journal/core.qnt`, `journal/anti_entropy.qnt`, `consensus/core.qnt`
Runtime conformance against formal artifacts	`Conformance-backed`	ITF trace replay, Telltale parity, conformance fixtures
Onion accountability witness return and verification	`Conformance-backed`	Simulator Telltale parity and `reply_block_accountability` control-plane scenarios
Hold availability and custody-failure boundaries	`Conformance-backed`	`crates/aura-simulator/tests/adaptive_privacy_phase_six.rs`, weak-connectivity and sparse-sync `Hold` scenarios
Failure-class boundaries and local-only failure	`Specified only`	No direct proof or conformance mapping recorded here
Error-channel privacy requirements	`Specified only`	No direct proof or conformance mapping recorded here

CI Verification Gates

Automated verification lanes wired into CI pipelines.

Core Verification

Gate	Command	Purpose
Property Monitor	`just ci-property-monitor`	Runtime property assertion monitoring
Simulator Telltale Parity	`just ci-simulator-telltale-parity`	Artifact-driven telltale vs Aura simulator differential comparison
Choreography Parity	`just ci-choreo-parity`	Session type projection consistency
Quint Typecheck	`just ci-quint-typecheck`	Quint specification type safety

Conformance Gates

Gate	Command	Purpose
Conformance Policy	`just ci-conformance-policy`	Policy rule validation
Conformance Contracts	`just ci-conformance-contracts`	Contract satisfaction checks

Formal Methods

Gate	Command	Purpose
Lean Build	`just ci-lean-build`	Compile Lean proofs
Lean Completeness	`just ci-lean-check-sorry`	Check for incomplete proofs (sorry)
Telltale Bridge	`just ci-telltale-bridge`	Cross-validation between Lean and Quint
Kani BMC	`just ci-kani`	Bounded model checking for unsafe code

CI Artifacts

Conformance artifacts upload to CI for failure triage:

artifacts/conformance/
├── native_coop/
│   └── scenario_seed_artifact.json
├── wasm_coop/
│   └── scenario_seed_artifact.json
└── diff_report.json

The diff report highlights specific mismatches for investigation.

Telltale parity and bridge lanes emit additional artifacts:

artifacts/telltale-parity/
└── report.json

artifacts/telltale-bridge/
├── bridge.log
├── bridge_discrepancy_report.json
└── report.json

artifacts/telltale-parity/report.json uses schema aura.telltale-parity.report.v1. artifacts/telltale-bridge/bridge_discrepancy_report.json uses schema aura.telltale-bridge.discrepancy.v1.

Bridge Pipeline Fixtures

aura-quint bridge pipeline checks use deterministic fixture inputs:

Fixture	Purpose
`positive_bundle.json`	Expected consistent cross-validation outcome
`negative_bundle.json`	Expected discrepancy detection outcome
`quint_ir_fixture.json`	Export/import pipeline coverage for Quint IR

Fixtures live in crates/aura-quint/tests/fixtures/bridge/.

Formal Verification Reference - Architecture and specification patterns
Verification and MBT Guide - Practical verification workflows
Simulation Infrastructure Reference - Generative simulation details
Testing Guide - Testing infrastructure and conformance testing

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