Post-Quantum Vulnerable

Documentation: Post-Quantum Vulnerable SSL and Recommended Countermeasures

Overview

The rise of quantum computing poses a direct threat to traditional cryptographic algorithms used in SSL/TLS, such as RSA, ECDSA, and Elliptic Curve Diffie-Hellman (ECDH). These algorithms rely on problems (like integer factorization and discrete logarithms) that quantum computers can solve efficiently using Shor’s algorithm, rendering current SSL/TLS protocols post-quantum vulnerable.

This document outlines how SSL/TLS can be vulnerable in a post-quantum context and provides recommendations for post-quantum secure alternatives.

⚠️ Post-Quantum Vulnerabilities in SSL/TLS

1. Key Exchange Vulnerabilities

Traditional key exchange mechanisms such as:

• RSA key exchange

• Elliptic Curve Diffie-Hellman (ECDH)

These are vulnerable because quantum computers can derive the private keys from intercepted public data using Shor’s algorithm.

2. Digital Signature Vulnerabilities

• RSA and ECDSA signatures can be forged with quantum algorithms.

• Intercepted SSL traffic today can be decrypted in the future using harvest-now, decrypt-later attacks.

🔐 Modern Post-Quantum Safe Ciphers (Hybrid and Pure)

To mitigate quantum risks, TLS implementations must transition to quantum-resistant cryptographic algorithms. These can be:

• Hybrid schemes: Combine classical and post-quantum algorithms (interoperable and backward compatible)

• Pure PQC schemes: Use only post-quantum algorithms (ideal for future-proofing)

📌 NIST-Recommended Post-Quantum Algorithms (2024)

✅ Recommended Cipher Suites (TLS 1.3 with PQC)

As of today, post-quantum cryptography is often integrated through TLS hybrid key exchanges via extensions like [x25519+kyber512] or via Open Quantum Safe (OQS) libraries.

Example Hybrid Cipher Suites (using NIST PQC algorithms):

1. TLS_AES_256_GCM_SHA384 + X25519+Kyber768

2. TLS_CHACHA20_POLY1305_SHA256 + Kyber512

3. TLS_AES_128_GCM_SHA256 + ECDHE + Kyber1024

⚠️ These are not yet formal cipher suite names; they represent the key exchange combinations used in hybrid TLS libraries like BoringSSL, OpenSSL with OQS, and AWS s2n-tls.

🧰 Implementation Options

Libraries supporting Post-Quantum TLS:

• Open Quantum Safe (OQS)

  • Extensions for OpenSSL, BoringSSL, and liboqs

• Google BoringSSL

  • Early experimental support for hybrid schemes

• AWS s2n-tls

  • Supports hybrid post-quantum TLS 1.2 and TLS 1.3

• Cloudflare and Google Chrome (experimental support in QUIC)

🔄 Migration Strategy

1. Evaluate inventory of TLS endpoints

   • Identify services using RSA/ECDSA and vulnerable ciphers.

2. Use hybrid schemes first

   • Interoperable with legacy clients while offering PQC protection.

3. Enable PQC cipher suites in controlled environments

   • Internal APIs, backend services, etc.

4. Monitor NIST and IETF standards

   • Stay aligned with official PQC cipher standardization efforts.

5. Implement TLS 1.3

   • Required for most PQC-ready key exchange implementations.

🚫 Ciphers to Deprecate Immediately

Avoid these in future-proof systems:

• TLS_RSA_WITH_AES_256_GCM_SHA384

• TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA

• TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384

• TLS_DHE_RSA_WITH_AES_256_CBC_SHA

These are based on RSA/ECDSA and vulnerable to quantum attacks.

NIST PQC Standardization Milestones

Summary

• SSL/TLS systems that rely on RSA/ECDSA are vulnerable to quantum attacks.

• Transitioning to post-quantum key exchange and signature schemes is critical.

• Adopt hybrid schemes like X25519+Kyber during the transition phase.

• Monitor evolving standards from NIST, IETF, and TLS WG.