ML-DSA keys in AWS KMS

AWS Key Management Service (AWS KMS) supports Module-Lattice Digital Signature Algorithm (ML-DSA) for post-quantum cryptographic signatures. This implementation follows the Federal Information Processing Standards (FIPS) 204 standard to help protect against future quantum computing threats. AWS KMS creates and protects all ML-DSA keys and signature operations in FIPS 140-3 Security Level 3 validated hardware security modules. To help balance security with performance, ML-DSA in AWS KMS offers three distinct security levels through different key specifications, ML_DSA_44, ML_DSA_65, and ML_DSA_87.

AWS KMS supports asymmetric key signatures for messages up to 4 KB using the RAW message type. For larger messages, you must externally compute the 64-byte message representation μ used in ML-DSA signing as defined in NIST FIPS 204 section 6.2. Use the EXTERNAL_MU message type in the AWS KMS Sign operation to specify this pre-processed 64-byte message. The signatures produced by the externally computed μ are the same as the RAW ones when using the same message and private key. Note that this signing is different from the "pre-hash" ML-DSA or HashML-DSA from section 5.4 of NIST FIPS 204.

For more information about using ML-DSA and the EXTERNAL_MU message type, see ML-DSA key specs.

For an example of using ML-DSA and the EXTERNAL_MU message type, see Offline verification with ML-DSA key pairs.