@webbuf/slhdsa

WebBuf 4 byte access

Public APIs keep WebBuf and FixedBuf wrappers. For native APIs use value.bytes or fixed.buf.bytes. This package unwraps selected native views at its WASM boundary; key/signature/secret formats and cryptographic behavior are unchanged. Inputs are not mutated and outputs retain their existing independent storage. Nonzero-offset selections are supported.

SLH-DSA (FIPS 205) stateless hash-based post-quantum digital signatures for WebBuf.

Preferred API

Use the message-level APIs for application code. They apply FIPS 205 context separation and default to hedged signing by generating addrnd with the platform CSPRNG through FixedBuf.fromRandom.

import {
  slhDsaSha2_128fKeyPair,
  slhDsaSha2_128fSign,
  slhDsaSha2_128fVerify,
} from "@webbuf/slhdsa";
import { WebBuf } from "@webbuf/webbuf";

const message = WebBuf.fromUtf8("Signed message");
const context = WebBuf.fromUtf8("example");
const { verifyingKey, signingKey } = slhDsaSha2_128fKeyPair();
const signature = slhDsaSha2_128fSign(signingKey, message, context);
const ok = slhDsaSha2_128fVerify(verifyingKey, message, signature, context);

The preferred APIs are available for all SHA2 and SHAKE SLH-DSA parameter sets.

Deterministic And Internal APIs

Seeded key generation and deterministic signing aliases are available for reproducible tests and advanced protocol work:

slhDsaSha2_128fKeyPairDeterministic(skSeed, skPrf, pkSeed);
slhDsaSha2_128fSignDeterministic(signingKey, message, context);

The slhDsa*SignInternal(...) and slhDsa*VerifyInternal(...) functions remain public for ACVP vectors and low-level conformance work. They expose FIPS 205 internal primitives and should not be the default application-facing API.

Testing

The package keeps NIST ACVP vector tests for the internal interface and adds round-trip, hedged-signing, deterministic-signing, and context-separation tests for the preferred message-level API.