SLH-DSA (SPHINCS+)

Stateless hash-based signatures standardized in FIPS 205. Security rests on the hash function — conservative assumptions, large signatures, slow signing.

This package ships the three SHA2 s (small-signature) sets via @noble/post-quantum (pure JS — works in Node and browsers, no WASM / COOP-COEP).

Loader	Variant	COSE (provisional)	PK	SK	Signature
loadSlhDsa128()	SLH-DSA-SHA2-128s	0x1220	32 B	64 B	7,856 B
loadSlhDsa192()	SLH-DSA-SHA2-192s	0x1221	48 B	96 B	16,224 B
loadSlhDsa256()	SLH-DSA-SHA2-256s	0x1222	64 B	128 B	29,792 B

note

COSE code points above are provisional for testbed/interop. Cryptosuite names follow W3C VC data-integrity patterns (slhdsa128-rdfc-2024, etc.).

warning

Unsuitable for the CTAP2 1024-byte WebAuthn buffer. Prefer where hash-only security matters and bandwidth is not tight (firmware, archival VCs).

import { loadSlhDsa128 } from "quantum-resistant-rustykey";

async function demo() {
  const slh = await loadSlhDsa128(); // or loadSlhDsa192 / loadSlhDsa256
  const kp = slh.keypair();
  const publicKey = await kp.get("public_key");
  const privateKey = await kp.get("private_key");

  const message = new TextEncoder().encode("Authored by RustyKey (SLH-DSA)");
  const signature = await slh.sign(message, privateKey);
  const isValid = await slh.verify(signature, message, publicKey);
  console.log("SLH-DSA-SHA2-128s valid?", isValid);
}

demo().catch(console.error);