Drops irpc from alknet-vault entirely. The vault's dispatch is now direct method calls on VaultServiceHandle — no VaultProtocol enum, no VaultMessage, no VaultServiceActor, no mpsc channel, no Service trait, no RemoteService trait, no postcard serialization. The vault is local-only by construction. The core security argument: irpc made the vault remote-capable by default (RemoteService generated unless no_rpc is passed). The IrohProtocol handler forwards all messages without auth. The docs framed 'register an ALPN' as a server-setup change. This is the default-insecure anti-pattern — security should be opt-in, not opt-out. ADR-025 inverts the default: local-only is the only mode, and remote access requires building a separate vault-server crate (a visible architectural act, not a flag flip). The actor path was already dead code — service.md said 'prefer VaultServiceHandle directly — no channel, no serialization.' The actor existed only to make irpc's Service trait work, which existed only to make RemoteService work, which was the footgun. VaultServiceHandle's Arc<RwLock> provides concurrent reads and exclusive writes — better throughput than the actor's sequential processing. DerivedKey serialization simplifies: always redact on serialize (for logging safety), reject '[REDACTED]' on deserialize with an error. No 'postcard preserves bytes' path. This resolves review #002 W8 (silent corruption on JSON-deserialized DerivedKey). Resolves: - OQ-21: remote vault access — resolved (not deferred). Not a vault crate feature; if needed, a separate vault-server crate with its own ADR. - C7: vault-server-crate question decided — not created now, not precluded. - C8: operation access policy table dissolved — all operations local-only by default; if a vault-server crate exposes some remotely, that crate defines the policy. - W8: DerivedKey JSON deserialization — resolved (reject redacted payloads). Amends ADR-005 (irpc remains for alknet-call, not for alknet-vault), ADR-018 (vault is even more standalone — zero RPC framework deps), ADR-019 (vault is the only layer, not just the only direct-caller layer), ADR-008 (vault integration point unchanged, but now local-only by construction).
158 lines
9.2 KiB
Markdown
158 lines
9.2 KiB
Markdown
---
|
|
status: draft
|
|
last_updated: 2026-06-22-25
|
|
---
|
|
|
|
# alknet-vault
|
|
|
|
Local key vault: BIP39 mnemonic generation, SLIP-0010 Ed25519 HD key
|
|
derivation, BIP-0032 secp256k1 derivation (feature-gated), and AES-256-GCM
|
|
encryption. Holds the master seed — the root of trust for all derived keys
|
|
and encrypted credentials in the alknet system.
|
|
|
|
## What This Crate Is
|
|
|
|
alknet-vault is a **standalone crate** with zero alknet crate dependencies
|
|
(ADR-018) and zero RPC framework dependencies (ADR-025). It provides the
|
|
cryptographic primitives and runtime API for managing the root of trust.
|
|
The CLI binary (the `alknet` crate) is the sole component that talks to the
|
|
vault directly (ADR-019) — handlers receive derived/decrypted material
|
|
through capabilities, never through a vault reference.
|
|
|
|
The vault is **not a network service**. It has no ALPN, no
|
|
`ProtocolHandler` implementation, no operations registered in the call
|
|
protocol (ADR-008, ADR-014), and no remote dispatch capability (ADR-025).
|
|
The vault is **local-only by construction** — direct method calls on
|
|
`VaultServiceHandle`, no actor, no message enum, no wire format. The master
|
|
seed and derived private keys never cross the network.
|
|
|
|
## Documents
|
|
|
|
| Document | Status | Description |
|
|
|----------|--------|-------------|
|
|
| [mnemonic-derivation.md](mnemonic-derivation.md) | draft | BIP39, SLIP-0010, BIP-0032, derivation paths, key types |
|
|
| [encryption.md](encryption.md) | draft | AES-256-GCM, EncryptedData, key versioning, HD derivation (ADR-020) |
|
|
| [service.md](service.md) | draft | VaultServiceHandle lifecycle, direct dispatch, cache, error model |
|
|
| [protocol.md](protocol.md) | draft | DerivedKey redaction, KeyType, serialization behavior |
|
|
|
|
## Applicable ADRs
|
|
|
|
| ADR | Title | Relevance |
|
|
|-----|-------|-----------|
|
|
| [003](../../decisions/003-crate-decomposition.md) | Crate Decomposition | alknet-vault's standalone position |
|
|
| [008](../../decisions/008-secret-service-integration.md) | Vault Integration Point | CLI-embedded, capability source |
|
|
| [010](../../decisions/010-alpn-router-and-endpoint.md) | ALPN Router and Endpoint | Ed25519 as default curve for TLS raw key identity |
|
|
| [014](../../decisions/014-secret-material-flow-and-capability-injection.md) | Secret Material Flow and Capability Injection | Capabilities carry vault-derived material |
|
|
| [018](../../decisions/018-vault-standalone-crate.md) | Vault as Standalone Crate | Zero alknet crate dependencies |
|
|
| [019](../../decisions/019-vault-assembly-layer-only.md) | Vault Assembly-Layer-Only Access | The assembly layer is the sole caller |
|
|
| [020](../../decisions/020-hd-derivation-for-encryption-keys.md) | HD Derivation for Encryption Keys | SLIP-0010 derivation, not PBKDF2; salt unused in v2 |
|
|
| [021](../../decisions/021-key-rotation-via-version-indexed-paths.md) | Key Rotation via Version-Indexed Paths | Version-indexed paths; `rotate` re-encrypts |
|
|
| [025](../../decisions/025-vault-local-only-dispatch.md) | Vault Local-Only Dispatch | Dropped irpc; direct method calls; local-only by construction |
|
|
|
|
## Relevant Open Questions
|
|
|
|
| OQ | Title | Status | Relevance |
|
|
|----|-------|--------|-----------|
|
|
| OQ-20 | Encryption key derivation | resolved (ADR-020) | HD derivation from seed; salt field unused in v2 |
|
|
| OQ-21 | Remote vault access | resolved (ADR-025) | Vault is local-only by construction; remote access requires a separate vault-server crate with its own ADR |
|
|
| OQ-22 | Key rotation mechanism | resolved (ADR-021) | Version-indexed paths; `rotate` method |
|
|
|
|
## Key Design Principles
|
|
|
|
1. **Standalone**: The vault depends on no alknet crate and no RPC framework.
|
|
It defines its own types and errors. External crates depend on the vault;
|
|
the vault depends on nothing in alknet.
|
|
2. **Assembly-layer only**: The vault's API is consumed by the CLI binary,
|
|
not by handlers. Handlers receive material through capabilities
|
|
(ADR-014). The vault is not on the wire.
|
|
3. **Local-only by construction**: The vault has no remote dispatch
|
|
capability. Direct method calls on `VaultServiceHandle` — no actor, no
|
|
message enum, no wire format (ADR-025). Remote access, if ever needed,
|
|
requires a separate crate with its own ADR.
|
|
4. **Zeroize everything sensitive**: The mnemonic, seed, derived private
|
|
keys, encryption keys, and cached keys all implement `Zeroize` and
|
|
`ZeroizeOnDrop`. Secret material does not linger in freed heap memory.
|
|
5. **Deterministic derivation**: The same mnemonic + passphrase + path
|
|
always produces the same key. Derivation is reproducible across runs
|
|
and across nodes.
|
|
6. **OsRng for nonces**: AES-GCM IVs and any cryptographic nonces use
|
|
`OsRng` (or equivalent CSPRNG), never `rand::random()`. IV reuse under
|
|
the same key is catastrophic for GCM.
|
|
7. **No `unwrap()` or `expect()` outside tests**: vault operations
|
|
propagate errors. A poisoned lock is recovered with
|
|
`unwrap_or_else(|e| e.into_inner())`, not `unwrap()`. A panic in one
|
|
vault operation must not brick the vault for all other operations.
|
|
|
|
## Security Constraints
|
|
|
|
These are security-critical implementation requirements, not architectural
|
|
decisions (the architecture is locked by the ADRs above). They are
|
|
documented here so implementation agents don't miss them. See
|
|
[service.md → Security Constraints](service.md#security-constraints) for
|
|
the full list.
|
|
|
|
- **OsRng for IVs**: AES-GCM IVs must use `OsRng`, not `rand::random()`. The
|
|
current source uses `rand::random()` — this is a known drift from the
|
|
spec and must be corrected during implementation sync.
|
|
- **Zeroized drop**: `Seed`, `Mnemonic`, `ExtendedPrivKey`,
|
|
`Secp256k1ExtendedPrivKey`, `EncryptionKey`, `CachedKey`, and
|
|
`DerivedKey` all derive `Zeroize` and `ZeroizeOnDrop`. The cache must
|
|
clear on drop, not just on explicit `lock()`.
|
|
- **No `unwrap()` outside tests**: poisoned lock recovery uses
|
|
`unwrap_or_else(|e| e.into_inner())` or explicit error propagation. The
|
|
current source uses `unwrap()` in `VaultServiceHandle` methods — this
|
|
is a known drift and must be corrected.
|
|
- **DerivedKey redaction in serialization**: `DerivedKey` serializes the
|
|
`private_key` as `"[REDACTED]"` in all formats (ADR-025 dropped the
|
|
postcard/remote path that previously preserved bytes in binary formats).
|
|
Deserialization rejects `"[REDACTED]"` with an error (resolves review
|
|
#002 W8). The redaction is a defense-in-depth measure for logging safety,
|
|
not the primary control — the primary control is that `DerivedKey` never
|
|
crosses the call protocol wire (ADR-014).
|
|
|
|
## Known Source Drift
|
|
|
|
The vault crate carries over source from the POC. The following items are
|
|
known divergences between the current source and the spec. All must be
|
|
corrected during implementation sync. This table is the single source of
|
|
truth for drift tracking — if an item is fixed in source, update this table.
|
|
|
|
| # | Item | Current source behavior | Target behavior (per spec) | Source location | Spec reference |
|
|
|---|------|------------------------|-----------------------------|-----------------|----------------|
|
|
| 1 | IV generation | `rand::random()` | `OsRng` (CSPRNG) | `encryption.rs` L133 | [encryption.md → Security Constraints](encryption.md#security-constraints), [service.md → Security Constraints](service.md#security-constraints) |
|
|
| 2 | RwLock `unwrap()` | `unwrap()` on every `RwLock` acquisition (L142, 161, 182, 191, 196, 227, 264, 307, 340, 367) | `unwrap_or_else(\|e\| e.into_inner())` for poisoned lock recovery | `service.rs` (see line numbers) | [service.md → Security Constraints](service.md#security-constraints) |
|
|
| 3 | `CURRENT_KEY_VERSION` | `1` (HD-derived, but v1 is reserved for TS PBKDF2 legacy per ADR-020) | `2` (HD-derived, per ADR-020) | `encryption.rs` | [encryption.md → Key Versioning](encryption.md#key-versioning), [ADR-020](../../decisions/020-hd-derivation-for-encryption-keys.md) |
|
|
| 4 | irpc dependency | `VaultProtocol` enum with `#[rpc_requests]`, `VaultServiceActor`, `Client<VaultProtocol>`, irpc/postcard deps | Remove entirely — direct method calls on `VaultServiceHandle` (ADR-025) | `protocol.rs`, `service.rs`, `Cargo.toml` | [ADR-025](../../decisions/025-vault-local-only-dispatch.md) |
|
|
| 5 | `DerivedKey` dual serialization | JSON redacts, postcard preserves bytes | Always redact on serialize; reject `"[REDACTED]"` on deserialize with error (ADR-025, resolves W8) | `protocol.rs` | [protocol.md → Serialization Redaction](protocol.md#serialization-redaction), [ADR-025](../../decisions/025-vault-local-only-dispatch.md) |
|
|
| 6 | `HashMap::clear` zeroization | `KeyCache::clear()` removes entries and relies on `CachedKey`'s `Drop` impl for zeroization | Verify `HashMap::clear()` actually drops values (it does, but worth a test) | `cache.rs` | [service.md → Security Constraints](service.md#security-constraints) |
|
|
|
|
## Public API
|
|
|
|
The vault re-exports its primary types from the crate root:
|
|
|
|
```rust
|
|
// Mnemonic and seed
|
|
pub use mnemonic::{Language, Mnemonic, Seed};
|
|
|
|
// Derivation
|
|
pub use derivation::{DerivationError, ExtendedPrivKey, PATHS};
|
|
|
|
// Encryption
|
|
pub use encryption::{EncryptedData, EncryptionError};
|
|
|
|
// Key types (DerivedKey, KeyType)
|
|
pub use protocol::{DerivedKey, KeyType};
|
|
|
|
// Service (runtime)
|
|
pub use service::{VaultServiceError, VaultServiceHandle};
|
|
|
|
// Cache
|
|
pub use cache::CacheConfig;
|
|
```
|
|
|
|
The `secp256k1` feature flag gates Ethereum (BIP-0032) derivation:
|
|
|
|
```rust
|
|
#[cfg(feature = "secp256k1")]
|
|
pub mod ethereum;
|
|
``` |