This document provides detailed information about the security features and considerations of the PQC-IIoT crate.

For the project’s invariant-level security contract, see SECURITY_INVARIANTS.md at the repository root. That document is the reference for “what must always remain true” under adversarial conditions (replay, rollback, partitions, broker compromise).

• Cryptographic Primitives
• Protocol Security
• Implementation Security
• Best Practices
• Threat Model
• Security Considerations

• NIST Round 3 finalist
• Security levels:
  • Kyber512 (Level 1)
  • Kyber768 (Level 3, recommended)
  • Kyber1024 (Level 5)
• Based on Module-LWE
• Constant-time implementation
• Side-channel resistant

• NIST Round 3 finalist
• Security levels:
  • LightSaber (Level 1)
  • Saber (Level 3, recommended)
  • FireSaber (Level 5)
• Based on Module-LWR
• Optimized for embedded systems
• Constant-time implementation

• NIST Round 3 finalist
• Security levels:
  • Falcon-512 (Level 1)
  • Falcon-1024 (Level 5)
• Based on NTRU lattices
• Compact signatures
• Fast verification

• NIST Round 3 finalist
• Security levels:
  • Dilithium2 (Level 2)
  • Dilithium3 (Level 3, recommended)
  • Dilithium5 (Level 5)
• Based on Module-LWE
• Balanced performance
• Robust implementation

• Provisioned identity (strict-mode) via signed operational certificates + key announcements bound to peer id/topic.
• v1 per-message hybrid encryption (Kyber + X25519 → AES-256-GCM) with signature authentication and sliding-window replay protection.
• v4 forward-secure sessions (authenticated handshake + hybrid DH+KEM double ratchet) with topic/context binding, bounded out-of-order acceptance, and in-session PQC refresh.
• Partition-aware policy + revocation updates (CA-signed, monotonic, retained) with fail-closed gates for high-risk operations.
• Asymmetric-cost DoS containment: size limits + peer-id sanitation + per-peer/global token-bucket budgets before expensive crypto.

• Signed payload mode: authenticity-only of application payloads when peer keys are pinned.
• Custom secure session mode: confidentiality + integrity + anti-replay at the application layer (not OSCORE/DTLS).
• OSCORE mode (RFC 8613): standards-aligned message protection (feature coap-oscore).
• For interoperability/compliance-critical deployments, OSCORE with a standard AKE (e.g., EDHOC) or DTLS is the “industrial” transport/security boundary.

• Stack allocation where possible
• Zeroization of sensitive data
• Bounds checking
• No undefined behavior

• Constant-time operations
• Memory access patterns
• Branch-free code
• Cache timing protection

• Secure error reporting
• No information leakage
• Graceful failure
• Recovery mechanisms

1. Generation

   // Use recommended security levels
   let kyber = Kyber::new_with_level(KyberSecurityLevel::Kyber768);
   let falcon = Falcon::new_with_level(FalconSecurityLevel::Falcon512);

2. Storage

   // Store keys securely
   key_storage.store_public_key(&pk)?;
   key_storage.store_secret_key(&sk)?;

3. Rotation

   // Configure key rotation
   kyber.with_key_rotation_interval(Duration::from_secs(3600));

1. MQTT

   // Strict mode requires provisioning (no TOFU):
   // - pin `trust_anchor_ca_sig_pk`
   // - install an `OperationalCertificate` for this identity
   //
   // See docs/mqtt.md for the end-to-end flow.
   let _client = SecureMqttClient::new("localhost", 1883, "client_id")?;

2. CoAP

   // Configure secure client
   let client = SecureCoapClient::new()?
       .with_dtls_config(dtls_config)?
       .with_acl(acl_rules)?;

• Quantum computing attacks
• Classical cryptanalysis
• Side-channel attacks
• Fault injection

• Man-in-the-middle
• Replay attacks
• Denial of service
• Eavesdropping

• Memory corruption
• Timing attacks
• Power analysis
• Fault injection

• 32-bit processor
• 32KB RAM minimum
• 128KB Flash minimum
• Hardware RNG

• Key generation time
• Encryption/decryption time
• Signature/verification time
• Memory usage

1. Assessment

   • Evaluate security requirements
   • Choose appropriate algorithms
   • Configure security levels

2. Implementation

   • Follow best practices
   • Enable security features
   • Configure monitoring

3. Maintenance

   • Regular updates
   • Key rotation
   • Security audits

1. Monitor security advisories
2. Evaluate impact
3. Plan updates
4. Test changes

1. Review patches
2. Test updates
3. Deploy changes
4. Verify security

1. Detect incidents
2. Assess impact
3. Contain threat
4. Recover systems
5. Learn from incident