ArkheKernel

Deterministic Rust microkernel with bit-identical replay and post-quantum sealed audit chains.

Changelog · License

Identical inputs produce bit-identical WAL bytes (BLAKE3-keyed chain) → bit-identical state, byte-for-byte. Hybrid Ed25519 + ML-DSA 65 (NIST FIPS 204, CNSA 2.0) is a first-class signing class — post-quantum migration is built in, not bolted on.

Quick start

Five-minute build, no formal-verification dependencies required:

use arkhe_kernel::abi::{CapabilityMask, EntityId, Principal, Tick, TypeCode};
use arkhe_kernel::state::{ActionCompute, ActionContext, InstanceConfig, Op};
use arkhe_kernel::{ArkheAction, Kernel};
use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, ArkheAction)]
#[arkhe(type_code = 1, schema_version = 1)]
struct Hello;

impl ActionCompute for Hello {
    fn compute(&self, _ctx: &ActionContext) -> Vec<Op> {
        vec![Op::SpawnEntity {
            id: EntityId::new(1).unwrap(),
            owner: Principal::System,
        }]
    }
}

let mut kernel = Kernel::new();
kernel.register_action::<Hello>();
let inst = kernel.create_instance(InstanceConfig::default());
kernel.submit(inst, Principal::System, None, Tick(0), TypeCode(1), Vec::new()).unwrap();
let report = kernel.step(Tick(0), CapabilityMask::SYSTEM);
assert_eq!(report.actions_executed, 1);
assert_eq!(report.effects_applied, 1);

End-to-end deterministic-replay proof:

cargo run -p dice

Why ArkheKernel

• Hybrid PQC baseline from day 1. SignatureClass is {None, Ed25519, Hybrid} out of the box — no opt-in feature flag, no migration project. Hybrid mode dual-signs every WAL record (Ed25519 + ML-DSA 65, AND-mode verify) so audit chains stay verifiable through the post-quantum transition.
• Byte-identical replay invariant. Most event-sourcing systems guarantee state-equivalence under replay. ArkheKernel guarantees the serialized WAL bytes themselves match across runs, runtimes, and CPU architectures. The chain hash (BLAKE3-keyed over postcard-canonical records) is the public invariant.
• Tamper-evident, anchored verification. Wal::verify_chain_anchored / replay_into_verified authenticate a WAL against a caller-supplied trust anchor (minimum signature tier + pinned verifying keys + expected chain tip) — rejecting signature downgrade, key substitution, and tail truncation. The kernel supplies the mechanism; the caller owns the trust-root policy. Untrusted snapshots gate the same way via KernelSnapshot::deserialize_verified.
• Formal verification anchored. TLA+ refinement modules cover chain hash determinism, state-machine refinement, replay invariance, and observer chain-non-affecting. Apalache typecheck is a CI gate, not a side project. A machine-readable axiom inventory pins every cited invariant to its implementation witness.

Architecture

+----------------------------------------+
|  persist  WAL chain, snapshots,        |  BLAKE3 keyed-hash, postcard
|           Hybrid PQC signatures        |  canonical bytes, replay
+------------------^---------------------+
                   |
+------------------+---------------------+
|  runtime  Kernel orchestrator,         |  step-stage commit-or-rollback,
|           observer pipeline,           |  Effect<Authorized,'i> phantom
|           InstanceView read API        |
+------------------^---------------------+
                   |
+------------------+---------------------+
|  state    Action / Component / Event   |  sealed traits, per-instance
|           types                        |  store, authorization phantoms
+------------------^---------------------+
                   |
+------------------+---------------------+
|  abi      EntityId / TypeCode /        |  identifiers, principals,
|           CapabilityMask / errors      |  capability bits
+----------------------------------------+

Single-direction DAG, pub(crate) cross-stratum edges only. The layer-DAG CI gate catches reverse imports as a structural error before they become a runtime bug.

Determinism guarantees

• A1 D1-Total — bit-identical WAL records across runs given the same config + canonical input sequence + manifest digest.
• A2 single-thread — Kernel: !Sync via PhantomData<Rc<()>>. The kernel is provably single-threaded at the type level.
• A12 panic-free — every kernel-internal Drop is total; no reachable panic in production code paths.
• A14 header pinning — WAL header pins kernel semver, ABI version, postcard version, BLAKE3 version, world id, and manifest digest. Replay against an incompatible header is a structural error, not a silent bit-rot.

Layer A — 7 catastrophic byte-identity invariants

A small set of byte-level guarantees where any change invalidates every chain ever produced. Concrete examples:

• DOMAIN_CTX — the BLAKE3 chain key derivation literal is pinned via a frozen-hex regression test. Any edit to the literal breaks every pre-existing WAL chain.
• WAL postcard field order — the on-wire field layout is pinned; a reorder changes chain hash inputs.
• #[derive(ArkheAction | ArkheComponent | ArkheEvent)] byte-emission — derive macros pin the canonical-encoding byte sequence so a silent AST mutation, varint-behaviour shift, or field reorder is caught before it reaches the chain hash.

Escalating a Layer A invariant requires an 8-field audit-trail entry in formal/axiom-test-cite.toml — date, commit hash, user consent, rationale, literal diff, chain-invalidation status, verify-chain reference, and spec anchor.

Full axiom catalog (A1–A24 + S1) → book/.

Crypto stack (supply-chain reviewed)

#![forbid(unsafe_code)], no async, no std::thread, no HashMap (only BTreeMap / BTreeSet for deterministic iteration).

Crypto provider extensibility

Drop-in HSM / KMS providers without patching kernel code. The PqcSigner and PqcVerifier traits are sealed — only same-crate impls satisfy them — so the kernel stays sealed while the provider seam stays open:

pub trait PqcSigner: private_seal::Sealed + Send + Sync {
    fn sign(&self, msg: &[u8]) -> Result<Vec<u8>, PqcSignError>;
    fn verifying_key_bytes(&self) -> Vec<u8>;
}

The current build ships a software-only ML-DSA 65 signer (SoftwareMlDsa65Signer); HSM / KMS providers integrate by adding a sealed-trait extension impl in the same crate without touching the kernel surface.

Formal verification

Optional path — required for contributors touching the formal layer, not for first-time users.

• 5 verification tiers — 25 invariants (24 axioms + S1) tagged as machine-checked (TLA+ + Kani, 9), type-proven (Rust types, 10), type-adjacent (sealed-trait shape pins, 4), runtime-asserted (observer first-panic eviction, 1), or social-contract (S1: clock monotonicity). See book/ for the full per-axiom breakdown.
• TLA+ refinement — five refinement modules (cr1 chain hash invariant, cr2 state-machine refinement, cr3 replay determinism, cr4 observer capability confinement, r4_implementation_refinement layer-DAG enforcement) on a shared runtime_core base. Apalache typecheck on every push.
• Kani harness suite — 5 implementation-level proofs in the sibling ArkheForge repository (published alongside v0.14): authorize, dispatch, replay, memory_bounds_check, and hybrid_and_mode (PQC AND-mode verify).
• Axiom-cite gate — formal/axiom-test-cite.toml is a machine-readable inventory; CI verifies every cited TLA+ invariant name appears in its tla_module file and every cited impl test exists as fn <name> in some cited path. Catches inventory drift, not theorem soundness.
• Process discipline — an 8-category cosmetic-vs-semantic commit denylist guards security-critical, formal-artifact, timing-side- channel, and fuel-budget surfaces from drive-by edits.

Performance

ArkheKernel ships three signing modes (SignatureClass::{None, Ed25519, Hybrid}); throughput depends on the choice:

Numbers measured on Apple M3 Max, single-thread, via criterion (95% confidence intervals, outlier detection, warm-up). Reproduce locally:

cargo bench -p arkhe-kernel

Per-primitive measurements live in arkhe-kernel/benches/ (chain_hash, signing, codec, dispatch). HTML reports with full distribution graphs land in target/criterion/ after cargo bench.

These are honest performance disclosures, not audited industry benchmarks — the bench code is the spec, and external readers reproduce on their own hardware to verify.

Stability

v0.14 — pre-public. The kernel version advances only when a release changes the persisted wire format (the v0.13 → v0.14 ML-DSA stabilization being the first such advance); cosmetic fixes keep the version. Version 1.0 is intentionally never reached.

Documentation

• Architecture book: book/ (cd book && mdbook serve for local preview)
• API reference: docs.rs/arkhe-kernel
• Operator runbook: docs/runbook/
• Build reproducibility: docs/build-reproducibility.md

License

Dual-licensed under either of:

• Apache License 2.0, (LICENSE-APACHE)
• MIT License, (LICENSE-MIT)

at your option. Contributions are accepted under the same dual-license terms.

Powered by ArkheKernel — bit-identical causality across virtual worlds.