openssl

FIPS 203, 204 and 205 explained: ML-KEM, ML-DSA and SLH-DSA tested with OpenSSL

FIPS 203 (ML-KEM) defines how to agree on a secret key, and FIPS 204 (ML-DSA) and FIPS 205 (SLH-DSA) how to sign, all three resistant to a quantum computer and final since August 2024. With OpenSSL 3.5.9 I measured their sizes: an ML-KEM-768 public key takes 1,184 bytes and an SLH-DSA-128s signature 7,856.