{
  "slug": "fn-dsa",
  "name": "FN-DSA",
  "aka": "Falcon",
  "kind": "Digital signature",
  "family": "Lattice (NTRU, fast-Fourier sampling)",
  "standard": "FIPS 206 (draft)",
  "standard_url": "https://csrc.nist.gov/projects/post-quantum-cryptography/post-quantum-cryptography-standardization",
  "body": "NIST",
  "date": "TBD (draft under review; final expected late 2026 or 2027)",
  "status": "Draft",
  "summary": "FN-DSA is NIST's name for Falcon, the fourth post-quantum signature scheme selected in 2022. It will be published as FIPS 206. As of 2026-09 the standard is still in draft; NIST submitted the initial public draft for approval in 2025-08 and a final standard is expected in late 2026 or 2027.",
  "parameter_sets": [
    {
      "name": "FN-DSA-512 (Falcon-512)",
      "category": 1,
      "pk": 897,
      "sk": 1281,
      "ct_or_sig": 666
    },
    {
      "name": "FN-DSA-1024 (Falcon-1024)",
      "category": 5,
      "pk": 1793,
      "sk": 2305,
      "ct_or_sig": 1280
    }
  ],
  "size_label": "Signature (approx., variable-length encoding)",
  "deployments": [
    "Blockchains and constrained protocols that need the smallest post-quantum signatures (about 666 bytes at category 1)",
    "Not yet approved for FIPS 140-3 validation until FIPS 206 is final"
  ],
  "audit_focus": [
    "The floating-point Gaussian sampler is the hardest part of any post-quantum standard to implement in constant time; audit emulated-FP paths and every platform-specific FPU behavior",
    "Key generation (NTRU solve) correctness and secret-dependent timing",
    "Signature encoding and the variable-length compression format",
    "Reference implementations still change between draft versions; verify against the exact draft the project targets"
  ],
  "references": [
    [
      "NIST PQC standardization project page",
      "https://csrc.nist.gov/projects/post-quantum-cryptography"
    ],
    [
      "FIPS 206 status update (NIST, 2025)",
      "https://csrc.nist.gov/presentations/2025/fips-206-fn-dsa-falcon"
    ],
    [
      "Falcon specification",
      "https://falcon-sign.info/"
    ]
  ],
  "url": "https://pqaudit.org/algorithms/fn-dsa/",
  "updated": "2026-09-12"
}