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securitycritical PriorityID: pqc-hybrid-mlkem-x25519-edge-tls-standard

Mandatory Hybrid ML-KEM/X25519 Key Encapsulation for Edge TLS Ingress

Mandates dual-mode hybrid post-quantum key encapsulation (X25519MLKEM768 / X25519Kyber768Draft00) across all ingress edge load balancers, TLS termination proxies, and internal microservice mesh boundaries. This neutralizes 'harvest-now, decrypt-later' (HNDL) adversarial vectors while preserving classical FIPS/RFC-compliant cryptographic fallback security. Any TLS listener configured solely with classical elliptic curves or RSA key transport violates edge transport policy.

Prohibited Anti-Pattern: Classical-Only ECDHE Key Exchange Permitted on Ingress Edge Terminations

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---
description: Mandatory Hybrid ML-KEM/X25519 Key Encapsulation for Edge TLS Ingress - Mandates dual-mode hybrid post-quantum key encapsulation (X25519MLKEM768 / X25519Kyber768Draft00) across all ingress edge load balancers, TLS termination proxies, and internal microservice mesh boundaries. This neutralizes 'harvest-now, decrypt-later' (HNDL) adversarial vectors while preserving classical FIPS/RFC-compliant cryptographic fallback security. Any TLS listener configured solely with classical elliptic curves or RSA key transport violates edge transport policy.
globs: infra/**/*.{ts,js,tf,json,yaml,yml}, src/edge/**/*.{ts,js}, src/server/**/*.{ts,js}, k8s/**/*.{yaml,yml}
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/pqc-hybrid-mlkem-x25519-edge-tls-standard"
---

# Mandatory Hybrid ML-KEM/X25519 Key Encapsulation for Edge TLS Ingress

> **Severity**: CRITICAL | **Category**: security
> **Anti-Pattern Warning**: Classical-Only ECDHE Key Exchange Permitted on Ingress Edge Terminations

## System Constraints
You are a Principal Security Architect enforcing Post-Quantum Cryptography (PQC) standards across infrastructure and edge services. You must enforce TLS 1.3 minimums and mandate hybrid ML-KEM/X25519 (X25519MLKEM768 or draft X25519Kyber768) key exchange mechanisms on all ingress entrypoints to counter harvest-now, decrypt-later (HNDL) adversaries. Reject legacy curve lists, non-hybrid configurations, TLS versions below 1.3 for public endpoints, and configurations lacking proactive quantum-safe posture.

## Strict Guidelines
- Edge TLS terminations MUST enforce TLS 1.3 as the strict minimum protocol version (`minVersion: 'TLSv1.3'`).
- Key exchange groups MUST prioritize hybrid post-quantum algorithms: `X25519MLKEM768` (preferred) or `X25519Kyber768Draft00` before classical fallbacks (`X25519`, `secp256r1`).
- Engineers MUST NOT permit pure classical key exchange (e.g., standard ECDHE with only P-256 or pure X25519) on public data-in-transit boundaries handling confidential customer payloads.
- Custom Node.js, Go, or Envoy reverse proxies MUST configure curve negotiation (`ecdhCurve`) to include `X25519MLKEM768:x25519_kyber768:X25519:secp256r1`.
- Services MUST enable Session Resumption (TLS session tickets / PSK) with cryptographically bound zeroized ticket keys rotated every 4 hours or less to prevent retroactive decryption of persisted session caches.
- Infrastructure-as-Code definitions (CDK, Terraform, Helm) MUST reject legacy TLS security policies lacking post-quantum support (e.g., AWS CloudFront Security Policy must use `TLSv1.3_2024` or higher with PQ-KEM enabled).

## Bad vs Good Implementations
### Edge HTTPS Server TLS Context Configuration

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: The server config allows TLS 1.2, omits hybrid post-quantum key encapsulation mechanisms, and relies exclusively on classical elliptic curves (prime256v1, classical X25519). Adversaries harvesting traffic today will decrypt these payloads when cryptographically relevant quantum computers (CRQCs) become operational.
```typescript
import https from 'node:https';
import fs from 'node:fs';

// CRITICAL FLAW: Enforces classical ECDH without post-quantum hybrid KEM.
// Vulnerable to Harvest-Now-Decrypt-Later (HNDL) quantum cryptanalysis.
const serverOptions: https.ServerOptions = {
  key: fs.readFileSync('/etc/ssl/certs/server.key'),
  cert: fs.readFileSync('/etc/ssl/certs/server.crt'),
  minVersion: 'TLSv1.2',
  ecdhCurve: 'prime256v1:X25519',
  ciphers: 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384'
};

export const edgeServer = https.createServer(serverOptions, (req, res) => {
  res.writeHead(200, { 'Content-Type': 'application/json' });
  res.end(JSON.stringify({ status: 'ok' }));
});
```

#### Production Standard (Correct)
> **Standard**: Configures strict TLS 1.3 and specifies hybrid ML-KEM/X25519 (X25519MLKEM768 and draft variants) as top priority curves. Classical fallback (X25519/P-256) ensures compatibility for legacy clients, but any quantum-capable client negotiates the hybrid KEM, rendering captured traffic immune to future quantum cryptanalysis.
```typescript
import tls from 'node:tls';
import https from 'node:https';
import fs from 'node:fs';

// Mandate Hybrid Post-Quantum Key Encapsulation (ML-KEM-768 + X25519)
// Supported in Node 22+ / OpenSSL 3.2+ / BoringSSL runtime engines
const pqcEcdhCurves = [
  'X25519MLKEM768',    // FIPS 203 finalized ML-KEM hybrid
  'x25519_kyber768',   // Draft hybrid interoperability fallback
  'X25519',            // Classical RFC 7748 fallback
  'secp256r1'          // Classical NIST P-256 fallback
].join(':');

const secureTlsOptions: https.ServerOptions = {
  key: fs.readFileSync('/etc/ssl/certs/server.key'),
  cert: fs.readFileSync('/etc/ssl/certs/server.crt'),
  minVersion: 'TLSv1.3',
  maxVersion: 'TLSv1.3',
  ecdhCurve: pqcEcdhCurves,
  honorCipherOrder: true,
  // Session ticket key auto-rotation interval configuration
  ticketKeys: fs.readFileSync('/run/secrets/tls_current_ticket_key.bin')
};

export const edgeServer = https.createServer(secureTlsOptions, (req, res) => {
  res.writeHead(200, { 'Content-Type': 'application/json' });
  res.end(JSON.stringify({ status: 'quantum-secure' }));
});
```
Recommended MCP Servers (mcp-serverlist.com)

Equip agent with system tools to verify code for this stack.

TLS Cryptographic Auditor MCP
Scans TLS termination configs and active sockets for supported KEM groups and cipher curves.
Recommended Agent Skills (askills.dev)

Ready-to-use executable skill functions tailored to this stack.

Open Quantum Safe TLS Validator
Automated security validation skill utilizing liboqs and OpenSSL 3 to assert hybrid ML-KEM handshakes.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Mandatory Hybrid ML-KEM/X25519 Key Encapsulation for Edge TLS Ingress

Mandatory Hybrid ML-KEM/X25519 Key Encapsulation for Edge TLS Ingress defines an industrial-grade behavioral standard for security engineering. Mandates dual-mode hybrid post-quantum key encapsulation (X25519MLKEM768 / X25519Kyber768Draft00) across all ingress edge load balancers, TLS termination proxies, and internal microservice mesh boundaries. This neutralizes 'harvest-now, decrypt-later' (HNDL) adversarial vectors while preserving classical FIPS/RFC-compliant cryptographic fallback security. Any TLS listener configured solely with classical elliptic curves or RSA key transport violates edge transport policy. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Classical-Only ECDHE Key Exchange Permitted on Ingress Edge Terminations Without an explicit system instruction file, developers spend hours debugging silent failures.
Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure ModeAI Symptom (The Anti-Pattern)SeverityProduction Impact & Remedy
AI Hallucination & Deprecation DriftClassical-Only ECDHE Key Exchange Permitted on Ingress Edge TerminationsCritical
Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production.
Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture InconsistencyAI assistants produce mixed paradigms across files, creating fragmented codebase conventions.Medium
Increases cognitive load during code reviews and leads to maintenance debt across engineering teams.
Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.
Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

1

Edge TLS terminations MUST enforce TLS 1.3 as the strict minimum protocol version (`minVersion

Edge TLS terminations MUST enforce TLS 1.3 as the strict minimum protocol version (`minVersion: 'TLSv1.3'`).

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
2

Key exchange groups MUST prioritize hybrid post-quantum algorithms

Key exchange groups MUST prioritize hybrid post-quantum algorithms: `X25519MLKEM768` (preferred) or `X25519Kyber768Draft00` before classical fallbacks (`X25519`, `secp256r1`).

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
3

Engineers MUST NOT permit pure classical key exchange (e.g., standard ECDHE with only P-256 or pure X25519) on public data-in-transit boundaries handling confidential customer payloads.

Engineers MUST NOT permit pure classical key exchange (e.g., standard ECDHE with only P-256 or pure X25519) on public data-in-transit boundaries handling confidential customer payloads.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
4

Custom Node.js, Go, or Envoy reverse proxies MUST configure curve negotiation (`ecdhCurve`) to include `X25519MLKEM768

Custom Node.js, Go, or Envoy reverse proxies MUST configure curve negotiation (`ecdhCurve`) to include `X25519MLKEM768:x25519_kyber768:X25519:secp256r1`.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
5

Services MUST enable Session Resumption (TLS session tickets / PSK) with cryptographically bound zeroized ticket keys rotated every 4 hours or less to prevent retroactive decryption of persisted session caches.

Services MUST enable Session Resumption (TLS session tickets / PSK) with cryptographically bound zeroized ticket keys rotated every 4 hours or less to prevent retroactive decryption of persisted session caches.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
6

Infrastructure-as-Code definitions (CDK, Terraform, Helm) MUST reject legacy TLS security policies lacking post-quantum support (e.g., AWS CloudFront Security Policy must use `TLSv1.3_2024` or higher with PQ-KEM enabled).

Infrastructure-as-Code definitions (CDK, Terraform, Helm) MUST reject legacy TLS security policies lacking post-quantum support (e.g., AWS CloudFront Security Policy must use `TLSv1.3_2024` or higher with PQ-KEM enabled).

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
Technical Questions & Answers

Frequently Asked Technical Questions

Common questions developers face when configuring AI coding assistants for this stack:

Q:Why is Mandatory Hybrid ML-KEM/X25519 Key Encapsulation for Edge TLS Ingress critical for AI coding assistants?

Mandates dual-mode hybrid post-quantum key encapsulation (X25519MLKEM768 / X25519Kyber768Draft00) across all ingress edge load balancers, TLS termination proxies, and internal microservice mesh boundaries. This neutralizes 'harvest-now, decrypt-later' (HNDL) adversarial vectors while preserving classical FIPS/RFC-compliant cryptographic fallback security. Any TLS listener configured solely with classical elliptic curves or RSA key transport violates edge transport policy. Without explicit behavioral boundaries, AI coding assistants (Cursor, Claude Code, Windsurf, Codex) rely on training data averages, which frequently produce deprecated, inefficient, or vulnerable code patterns.

Q:How does adopting this rule prevent AI hallucinations?

This rule explicitly declares what the AI must avoid (Classical-Only ECDHE Key Exchange Permitted on Ingress Edge Terminations) and prescribes verified positive examples. Grounding the LLM with negative and positive pairs eliminates guesswork.

Q:Which AI coding environments are supported?

This specification is multi-platform compatible: Cursor (.cursor/rules/*.mdc & .cursorrules), Anthropic Claude Code (CLAUDE.md), Windsurf (.windsurfrules), Codex / Cline (AGENTS.md), and GitHub Copilot (.github/copilot-instructions.md).

Q:Can I combine this rule with other technology stacks?

Yes. Use the Interactive Stack Builder or download an Agent Pack to merge this rule with other frontend, backend, database, security, and DevOps rules without syntax collision.

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