@noble/hashes 2.3.0: hmac

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify @noble/hashes.hmac in pkg:npm/%40noble/hashes@2.3.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40noble/hashes@2.3.0
Demonstrate these symbols/APIs:
  - @noble/hashes.hmac

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:3e566671ee67cb9d55d6eb1da504cf3e6d59a8c90bedd50f266cb1e993e71880","contract":["assert hmac computes one-shot authentication tag matching RFC 4231 test vectors for SHA-256 and SHA-512","assert hmac.create initializes streaming instance exposing blockLen and outputLen properties","assert hmac streaming instance update supports method chaining and matches one-shot computation","assert hmac streaming instance clone forks intermediate state into independent authenticators","assert hmac digestInto writes authentication tag directly into preallocated destination buffer","assert hmac throws TypeError on non-byte keys or invalid hash functions","assert hmac streaming methods throw on destroyed instance or undersized output buffer"],"goal":"verify @noble/hashes.hmac in pkg:npm/%40noble/hashes@2.3.0","kind":"HOW","packages":["pkg:npm/%40noble/hashes@2.3.0"],"schemaVersion":1,"symbols":["@noble/hashes.hmac"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40noble/hashes@2.3.0"],"schemaVersion":1,"subject":"pkg:npm/%40noble/hashes@2.3.0","symbols":["@noble/hashes.hmac"],"verifierAdapter":"node-typescript@1"}

import { hmac, _HMAC } from '@noble/hashes/hmac.js';
import { sha256, sha512 } from '@noble/hashes/sha2.js';
import { bytesToHex, utf8ToBytes } from '@noble/hashes/utils.js';

/**
 * Computes an HMAC authentication tag using the specified hash function.
 * @param {import('@noble/hashes/utils.js').CHash} hash
 * @param {Uint8Array} key
 * @param {Uint8Array} message
 * @returns {Uint8Array}
 */
export function computeHmac(hash, key, message) {
  return hmac(hash, key, message);
}

/**
 * Computes an HMAC digest and returns it as a lowercase hex string.
 * @param {import('@noble/hashes/utils.js').CHash} hash
 * @param {Uint8Array} key
 * @param {Uint8Array} message
 * @returns {string}
 */
export function computeHmacHex(hash, key, message) {
  return bytesToHex(hmac(hash, key, message));
}

/**
 * Creates an incremental HMAC streaming instance.
 * @param {import('@noble/hashes/utils.js').CHash} hash
 * @param {Uint8Array} key
 * @returns {import('@noble/hashes/hmac.js')._HMAC<any>}
 */
export function createHmacStream(hash, key) {
  return hmac.create(hash, key);
}

/**
 * Computes an HMAC across an array of message chunks and returns lowercase hex.
 * @param {import('@noble/hashes/utils.js').CHash} hash
 * @param {Uint8Array} key
 * @param {Uint8Array[]} chunks
 * @returns {string}
 */
export function computeHmacChunksHex(hash, key, chunks) {
  const stream = hmac.create(hash, key);
  for (const chunk of chunks) {
    stream.update(chunk);
  }
  return bytesToHex(stream.digest());
}

export { hmac, _HMAC, sha256, sha512, bytesToHex, utf8ToBytes };

{
  "name": "sample-noble-hashes-hmac",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-noble-hashes-hmac",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@noble/hashes": "2.3.0"
      }
    },
    "node_modules/@noble/hashes": {
      "version": "2.3.0",
      "resolved": "https://registry.npmjs.org/@noble/hashes/-/hashes-2.3.0.tgz",
      "integrity": "sha512-oN+QwyX7VSHotibwubG3kpzbwKrfnyR6OOO+3Nk/53ADL7FmgHHz4TgrbaYKvvOw09u6QTx0oiH1cNCIOuN0CQ==",
      "license": "MIT",
      "engines": {
        "node": ">= 20.19.0"
      },
      "funding": {
        "url": "https://paulmillr.com/funding/"
      }
    }
  }
}

{
  "name": "sample-noble-hashes-hmac",
  "version": "1.0.0",
  "description": "Clean-room verification sample for @noble/hashes.hmac in pkg:npm/%40noble/hashes@2.3.0",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@noble/hashes": "2.3.0"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify @noble/hashes.hmac in pkg:npm/%40noble/hashes@2.3.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40noble/hashes@2.3.0"
  ],
  "symbols": [
    "@noble/hashes.hmac"
  ]
}

import assert from 'node:assert';
import {
  hmac,
  _HMAC,
  sha256,
  sha512,
  computeHmac,
  computeHmacHex,
  createHmacStream,
  computeHmacChunksHex,
  bytesToHex,
  utf8ToBytes,
} from '../index.js';

// 1. assert hmac computes one-shot authentication tag matching RFC 4231 test vectors for SHA-256 and SHA-512
const tc1Key = new Uint8Array(20).fill(0x0b);
const tc1Data = utf8ToBytes('Hi There');
const tc1Mac256 = computeHmac(sha256, tc1Key, tc1Data);
assert(tc1Mac256 instanceof Uint8Array, 'computeHmac returns Uint8Array');
assert.strictEqual(tc1Mac256.length, 32, 'HMAC-SHA256 produces 32-byte tag');
assert.strictEqual(
  bytesToHex(tc1Mac256),
  'b0344c61d8db38535ca8afceaf0bf12b881dc200c9833da726e9376c2e32cff7',
  'HMAC-SHA256 matches RFC 4231 TC1'
);

const tc2Key = utf8ToBytes('Jefe');
const tc2Data = utf8ToBytes('what do ya want for nothing?');
assert.strictEqual(
  computeHmacHex(sha256, tc2Key, tc2Data),
  '5bdcc146bf60754e6a042426089575c75a003f089d2739839dec58b964ec3843',
  'HMAC-SHA256 matches RFC 4231 TC2'
);
assert.strictEqual(
  computeHmacHex(sha512, tc2Key, tc2Data),
  '164b7a7bfcf819e2e395fbe73b56e0a387bd64222e831fd610270cd7ea2505549758bf75c05a994a6d034f65f8f0e6fdcaeab1a34d4a6b4b636e070a38bce737',
  'HMAC-SHA512 matches RFC 4231 TC2'
);

// 2. assert hmac.create initializes streaming instance exposing blockLen and outputLen properties
const stream256 = createHmacStream(sha256, tc2Key);
assert.strictEqual(stream256.blockLen, 64, 'HMAC-SHA256 blockLen is 64');
assert.strictEqual(stream256.outputLen, 32, 'HMAC-SHA256 outputLen is 32');

const stream512 = createHmacStream(sha512, tc2Key);
assert.strictEqual(stream512.blockLen, 128, 'HMAC-SHA512 blockLen is 128');
assert.strictEqual(stream512.outputLen, 64, 'HMAC-SHA512 outputLen is 64');

// 3. assert hmac streaming instance update supports method chaining and matches one-shot computation
const chainedStream = createHmacStream(sha256, tc2Key);
const chainedRet = chainedStream
  .update(utf8ToBytes('what do '))
  .update(utf8ToBytes('ya want '))
  .update(utf8ToBytes('for nothing?'));
assert.strictEqual(chainedRet, chainedStream, 'update returns instance for fluent chaining');
const streamedTag = chainedStream.digest();
assert.strictEqual(
  bytesToHex(streamedTag),
  computeHmacHex(sha256, tc2Key, tc2Data),
  'streaming digest matches one-shot HMAC'
);

const chunkedHex = computeHmacChunksHex(sha256, tc2Key, [
  utf8ToBytes('what do '),
  utf8ToBytes('ya want '),
  utf8ToBytes('for nothing?'),
]);
assert.strictEqual(chunkedHex, computeHmacHex(sha256, tc2Key, tc2Data), 'chunked helper matches one-shot');

// 4. assert hmac streaming instance clone forks intermediate state into independent authenticators
const forkBase = createHmacStream(sha256, tc2Key);
forkBase.update(utf8ToBytes('prefix:'));
const branchAlpha = forkBase.clone();
const branchBeta = forkBase.clone();

branchAlpha.update(utf8ToBytes('route-alpha'));
branchBeta.update(utf8ToBytes('route-beta'));

const tagAlpha = bytesToHex(branchAlpha.digest());
const tagBeta = bytesToHex(branchBeta.digest());
assert.notStrictEqual(tagAlpha, tagBeta, 'Cloned branches produce distinct digests');
assert.strictEqual(
  tagAlpha,
  computeHmacHex(sha256, tc2Key, utf8ToBytes('prefix:route-alpha')),
  'Branch Alpha matches independent computation'
);
assert.strictEqual(
  tagBeta,
  computeHmacHex(sha256, tc2Key, utf8ToBytes('prefix:route-beta')),
  'Branch Beta matches independent computation'
);

// 5. assert hmac digestInto writes authentication tag directly into preallocated destination buffer
const destBuf = new Uint8Array(32);
const intoStream = createHmacStream(sha256, tc2Key);
intoStream.update(tc2Data);
intoStream.digestInto(destBuf);
assert.strictEqual(
  bytesToHex(destBuf),
  computeHmacHex(sha256, tc2Key, tc2Data),
  'digestInto fills buffer accurately'
);

// 6. assert hmac throws TypeError on non-byte keys or invalid hash functions
assert.throws(() => {
  hmac(sha256, 'string-key', tc2Data);
}, /expected Uint8Array/i, 'throws TypeError on string key');

assert.throws(() => {
  hmac(() => {}, tc2Key, tc2Data);
}, /expected hash wrapped by utils.createHasher/i, 'throws TypeError on unwrapped hash function');

// 7. assert hmac streaming methods throw on destroyed instance or undersized output buffer
assert.throws(() => {
  intoStream.update(utf8ToBytes('after destroy'));
}, /hash was destroyed/i, 'update throws after destruction');

assert.throws(() => {
  intoStream.digest();
}, /hash was destroyed/i, 'digest throws after destruction');

const smallBuf = new Uint8Array(16);
const freshStream = createHmacStream(sha256, tc2Key);
assert.throws(() => {
  freshStream.digestInto(smallBuf);
}, /expected length >= 32/i, 'digestInto throws RangeError on insufficient buffer length');

console.log('All @noble/hashes.hmac contract assertions passed.');