docs(architecture): resolve review #003 — type/API surface completeness

Review #003 found 11 critical, 14 warning, and 6 suggestion findings
after reviews #001 (governance/security) and #002 (cross-document
consistency/two-way-door audit) were resolved. The theme: types and
APIs that were *referenced* but never *defined*, and stale ADR sketches
that didn't match the now-updated spec docs.

Critical fixes (11):

- C1: DerivedKey #[derive(Deserialize)] contradicted the custom
  Deserialize that rejects "[REDACTED]" — dropped the derive, added
  explicit manual Serialize/Deserialize impls (protocol.md).
- C2: encrypt prose said "derived at PATHS::ENCRYPTION" but the
  signature takes key_version — updated to encryption_path_for_version
  (service.md).
- C3: derive_encryption_key returned DerivedKey, derive_encryption_key
  _for_version returned EncryptionKey (same cache) — unified on
  DerivedKey, defined CachedKey (service.md).
- C4: tokio vs std::sync::RwLock contradiction — specified
  std::sync::RwLock, dropped tokio from vault deps (ADR-018, ADR-025,
  service.md).
- C5: Missing drift rows in vault README — added #9 (key_version
  ignored) and #10 (rotate not implemented).
- C6: ADR-022 build_root_context and invoke() sketches omitted
  abort_policy (9 fields vs 10) — added the field to both sketches.
- C7: Capabilities type referenced 20+ times, never defined — added
  struct definition to core-types.md with Clone+Send+Sync, Zeroize,
  sealed builder API, immutability guard.
- C8: SessionOverlaySource on CallAdapter but never defined, crate
  violation (alknet-call can't depend on alknet-agent) — defined the
  trait in alknet-call (call-protocol.md), matching the IdentityProvider
  pattern.
- C9: CompositeOperationEnv dispatch fall-through was "a two-way door"
  — added contains() to OperationEnv trait, made the composite probe
  before dispatching, eliminating the sentinel ambiguity.
- C10: No API for Layer 2 (connection overlay) registration, CallConnection
  undefined — defined CallConnection struct + register_imported() API
  (call-protocol.md).
- C11: with_local signature diverged between two examples (4 args vs 5)
  — added capabilities as the 5th arg, made both examples consistent.

Warning fixes (14):

- W1: invoke_with_policy restructured as required method, invoke gets a
  default impl delegating to it — eliminates duplication across impls.
- W2: CachedKey defined (service.md).
- W3: EncryptionKey constructor/glue specified, added to re-export list.
- W4: Secp256k1ExtendedPrivKey defined, derive_ethereum_key glue shown.
- W5: encryption_path_for_version rejects version < 2 (v1 is TS PBKDF2).
- W6: Wire payload schemas for all event types + ResponseEnvelope →
  EventEnvelope conversion table (call-protocol.md).
- W7: Timeout section — deadline on OperationContext, composed calls
  inherit parent's deadline, CallAdapter::with_timeout().
- W8: Request ID generation spec — UUID v4 for composed calls, wire ID
  vs internal ID relationship for abort cascade.
- W9: unlock_new already-unlocked behavior specified (returns
  AlreadyUnlocked).
- W10: KeyType Serialize/Deserialize justification corrected (stale
  irpc reference removed).
- W11: OperationProvenance and CompositionAuthority defined inline in
  operation-registry.md (were only in ADR-022).
- W12: encrypt/decrypt free functions marked pub(crate), relationship
  to VaultServiceHandle methods stated.
- W13: rotate signature removed from encryption.md (it's a
  VaultServiceHandle method, not a free function).
- W14: CallAdapter::new() + with_session_source() + with_timeout()
  constructors shown.

Suggestion fixes (6): Seed: Clone note, VaultServiceInner invariant,
ExtendedPrivKey accessor signatures, CURRENT_KEY_VERSION location, ADR-018
stale actor text, derivation helpers re-export note.
This commit is contained in:
2026-06-23 10:56:05 +00:00
parent cb98f42cd4
commit 2e34590522
14 changed files with 1129 additions and 120 deletions

View File

@@ -1,6 +1,6 @@
---
status: draft
last_updated: 2026-06-22-25
last_updated: 2026-06-23
---
# Protocol
@@ -26,7 +26,7 @@ The result of key derivation. Holds the key type, private key, and public
key.
```rust
#[derive(Zeroize, Deserialize)]
#[derive(Zeroize)]
#[zeroize(drop)]
pub struct DerivedKey {
#[zeroize(skip)]
@@ -38,6 +38,12 @@ pub struct DerivedKey {
}
```
`DerivedKey` does **not** derive `Deserialize` via `#[derive]`. It has a **custom
`Deserialize` impl** that rejects redacted payloads — see
[Serialization Redaction](#serialization-redaction) below. (A derived
`Deserialize` would generate a default impl that conflicts with the manual one,
and would not produce the explicit redaction-rejection error the spec requires.)
The `#[zeroize(skip)]` attributes on `key_type` and `public_key` mean only
the `private_key` is zeroized when the `DerivedKey` is dropped. The public
key and key type are not secret material — zeroizing them is unnecessary
@@ -65,10 +71,13 @@ private key, regardless of format:
`"[REDACTED]"`. This is defense-in-depth — if a `DerivedKey` accidentally
ends up in a log, a JSON config, or debug output, the private key is not
exposed.
- **Deserialization**: rejects `private_key == "[REDACTED]"` with an error.
A JSON-deserialized `DerivedKey` with a redacted private key is invalid
and produces a deserialization error, not a corrupted key. This resolves
review #002 W8 (silent corruption on JSON-deserialized `DerivedKey`).
- **Deserialization**: a custom `Deserialize` impl rejects
`private_key == "[REDACTED]"` with a deserialization error (not a corrupted
key). This resolves review #002 W8 (silent corruption on JSON-deserialized
`DerivedKey`). The custom impl is required because `#[derive(Deserialize)]`
would generate a default impl that conflicts and would only fail incidentally
(serde type mismatch: string vs sequence), not with the explicit
redaction-rejection error the spec requires.
- **No binary-format preservation path.** ADR-025 dropped the postcard/remote
dispatch path that previously preserved private key bytes in binary
formats. `DerivedKey` is always used in-process (ADR-014: never appears
@@ -76,6 +85,49 @@ private key, regardless of format:
`DerivedKey` over the wire, it defines its own serialization for that
context — the vault's `DerivedKey` stays redact-always.
```rust
// Custom Serialize — always redacts private_key
impl serde::Serialize for DerivedKey {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where S: serde::Serializer {
use serde::SerializeStruct;
let mut s = serializer.serialize_struct("DerivedKey", 3)?;
s.serialize_field("key_type", &self.key_type)?;
s.serialize_field("private_key", "[REDACTED]")?; // never the real bytes
s.serialize_field("public_key", &self.public_key)?;
s.end()
}
}
// Custom Deserialize — rejects "[REDACTED]" with an error
impl<'de> serde::Deserialize<'de> for DerivedKey {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where D: serde::Deserializer<'de> {
#[derive(serde::Deserialize)]
struct DerivedKeyHelper {
key_type: KeyType,
private_key: Vec<u8>,
public_key: Vec<u8>,
}
let helper = DerivedKeyHelper::deserialize(deserializer)?;
// Reject redacted payloads — a JSON-deserialized DerivedKey with a
// redacted private key is invalid, not a corrupted key.
if helper.private_key == b"[REDACTED]" {
return Err(serde::de::Error::custom(
"DerivedKey.private_key is \"[REDACTED]\" — redacted payloads \
cannot be deserialized. JSON round-tripping a DerivedKey is \
not supported (the private key is gone)."
));
}
Ok(DerivedKey {
key_type: helper.key_type,
private_key: helper.private_key,
public_key: helper.public_key,
})
}
}
```
The redaction is **not the primary control** for keeping private keys off
the wire. The primary control is architectural: `DerivedKey` never appears
in call protocol payloads (ADR-014). The redaction is a safety net for
@@ -112,8 +164,10 @@ pub enum KeyType {
```
Tags `DerivedKey` and `CachedKey` so consumers know what they received.
`KeyType` is `Serialize`/`Deserialize` (it's part of the irpc protocol) and
`Clone` (it's not secret material — it's a tag).
`KeyType` is `Serialize`/`Deserialize` (retained for `EncryptedData` interop
and future use — ADR-025 removed the irpc dispatch path that previously
justified these derives, but the type remains serializable for structured
storage scenarios) and `Clone` (it's not secret material — it's a tag).
## Wire Format