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AWS KMS and Post Quantum Cryptography: 2026 Status

9 min read

AWS PQC Status as of April 2026

Amazon Web Services has been among the first large cloud providers to ship Post Quantum Cryptography in production. The picture by service:

  • AWS KMS: hybrid ML-KEM TLS for API calls.
  • ACM: hybrid ML-KEM TLS.
  • Secrets Manager: hybrid ML-KEM TLS.
  • s2n-tls: via AWS-LC, supports X25519MLKEM768.
  • s2n-quic: inherits PQC via AWS-LC.
  • CloudFront: progressive rollout of hybrid ML-KEM TLS.
  • ALB/NLB: evaluated on a service-by-service basis.

What's Hybrid, What's Pure PQC

All current AWS deployments use hybrid X25519MLKEM768. Pure ML-KEM is not yet default, consistent with industry pattern.

The Gap You Still Need to Close

AWS KMS's hybrid TLS protects the API call (the network path between your app and KMS). It does NOT automatically make your data-at-rest quantum-safe:

  1. KMS Customer Master Keys (CMKs) still use AES-256 internally with classical key-wrapping for key hierarchy.
  2. Customer-supplied encryption (SSE-C) uses AES-256 but you provide the key; classical key delivery from your side is your problem.
  3. Client-side encryption with AWS SDKs uses whatever algorithms you configure; PQC support depends on your SDK version.

To get end-to-end PQC, encrypt locally with a PQC-aware tool (QNSQY, open-source liboqs) before uploading to S3 or putting into DynamoDB.

Timeline

  • 2024: Hybrid ML-KEM TLS enabled across KMS, ACM, Secrets Manager.
  • 2025-2026: Expansion to more services.
  • 2027-2029: Pure PQC or at-rest PQC options expected as FIPS 140-3 validations complete.

Frequently Asked Questions

Does AWS KMS encrypt my data with ML-KEM?

Not directly at rest. AWS KMS uses AES-256 at rest with classical key wrapping. The hybrid ML-KEM deployment protects the TLS API call to KMS, not the ciphertext format KMS stores.

Should I use client-side encryption for PQC coverage?

Yes, for data with long confidentiality lifetimes. Encrypt with a PQC tool before uploading to S3. This protects against both AWS-compromised and HNDL scenarios.

Does AWS s2n-tls support PQC?

Yes. Via AWS-LC, s2n-tls supports X25519MLKEM768 hybrid key exchange. Same for s2n-quic.

When will AWS be fully PQC?

Industry estimates: 2029-2032 for full AWS infrastructure PQC. This aligns with NSA CNSA 2.0 application-layer deadline of 2030.

Sources

  1. AWS KMS PQC blog

Related Articles

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Originally published at quantumsequrity.com/blog/aws-kms-quantum-migration.