# MODULE-README: Security & Verification Domain
---
## I. Strategic Overview
### 1. The "Why"
This module validates the cryptographic integrity of linguistic registries before they are loaded into the active memory pool. It ensures that the **Linguistic DNA** remains untampered throughout the transit process from the compiler to the runtime sidecar.
### 2. System Impact
If this module is bypassed or compromised, the system becomes vulnerable to supply-chain attacks or **Linguistic Poisoning**. This could allow an attacker to inject malicious or corrupted trait mappings, causing the capability engine to serve incorrect instructions that break search indexing or UI rendering.
### 3. Design Patterns
* **JWS Verification**: Implements the standard for cryptographically proving that a registry snapshot was issued by an authoritative source.
* **Pre-Hydration Gate**: Acts as a mandatory check in the `ISnapshotProvider` flow, blocking the `Atomic Reference Swap` if verification fails.
### 4. Local Glossary
* **JWS Verification**: The process of cryptographically proving that a registry snapshot was issued by an authoritative source.
* **Linguistic Poisoning**: A threat vector where incorrect trait mappings are injected to degrade search quality or rendering accuracy.
* **WORM Signature**: The unique cryptographic hash tied to a specific Write-Once, Read-Many snapshot.
---
## II. Technical Interface
### 1. Primary Capability
| `verify_snapshot()` | `&str` (Payload), `&str` (Signature) | `Result<(), LmsError>` | Validates that a registry payload matches its authoritative signature. |
### 2. Side Effects & SLIs
* **Telemetry**: Records `SecurityFault` events when verification fails, which are prioritized as `ERROR` level logs.
* **Performance**: Target latency: **< 1ms** (payload size dependent). Complexity: **O(N)** where N is the payload size.
* **Dependencies**: Relies on `crate::core::resolver::bcp47::LmsError` for standardized error propagation.
### 3. Quirks & Invariants
* **Fail-Fast**: Any signature mismatch results in a hard `Err`, immediately aborting the hydration process.
* **Invariant**: The verifier must never allow an empty or whitespace-only signature to pass, regardless of the payload state.
---
## III. Usage & Implementation
### 1. Basic Instantiation
```rust
use crate::security::verifier::verify_snapshot;
fn main() {
let payload = r#"{"registry": "data"}"#;
let signature = "valid-lms-signature";
// Standard verification call
let result = verify_snapshot(payload, signature);
// Explicit use to satisfy the compiler and prove the logic gate is operational
assert!(result.is_ok());
}
```
### 2. The "Golden Path" Example
```rust
use crate::security::verifier::verify_snapshot;
use crate::core::resolver::bcp47::LmsError;
fn main() -> Result<(), LmsError> {
let payload = r#"{"locales": [{"id": "ar-EG"}]}"#;
let forged_signature = "invalid-sig";
// Attempting to verify a forged payload
let result = verify_snapshot(payload, forged_signature);
// Verify that the system identifies the security fault
match result {
Err(LmsError::SecurityFault(msg)) => {
println!("Verification blocked: {}", msg);
Ok(())
},
_ => panic!("Security check failed to intercept forged signature"),
}
}
```
---
## IV. Development & Extension Guide
### 1. How to Build it Up
To extend the security logic (e.g., adding Public Key Pinning or Hardware Security Module (HSM) support):
1. **Red Phase**: Add a failing test case in `verifier.rs` demonstrating the new threat vector or required check.
2. **Implementation**: Update the `verify_snapshot` function and mirror the `# Logic Trace` with `// [STEP X]` comments.
3. **Audit**: Ensure no heavy heap allocations are introduced that would breach the performance budget for large registry payloads.
4. **Verification**: Run `just verify-all` to confirm that the security gate still permits valid "Golden Set" registries.
### 2. Troubleshooting & Common Failures
* **SecurityFault**: Usually indicates a version mismatch between the Compiler and the SDK. Verify that the SDK public key matches the compiler's private key pair.
* **IntegrityViolation**: If the payload is malformed before it reaches the verifier, hydration will fail in Phase 0.
---
## V. Metadata
* **Author**: Francis Xavier Wazeter IV
* **Version**: 0.9.7
* **File Created**: 2026-05-02
* **Last Updated**: 2026-05-02
* **License**: GNU GPL v3
---
### Architect's Note for AI Agents
When modifying this module, the **Security-First** constraint is absolute. Do not suggest "bypass" flags for development or testing that could leak into production. All verification failures must result in a `SecurityFault` to trigger the system's **Circuit Breaker** and prevent corrupted data from entering the Flyweight pool.