noble-ed25519

Fastest 5KB JS implementation of ed25519 signatures.

• ✍️ EDDSA signatures compliant with RFC8032, FIPS 186-5
• 🪢 Consensus-friendly, compliant with ZIP215
• 🔖 SUF-CMA (strong unforgeability under chosen message attacks) and SBS (non-repudiation / exclusive ownership)
• 🪶 3.66KB (gzipped)

The module is a sister project of noble-curves, focusing on smaller attack surface & better auditability. Curves are drop-in replacement and have more features: ristretto255, x25519 / curve25519, ed25519ph, hash-to-curve, oprf. To upgrade from v1 to v2, see Upgrading.

This library belongs to noble cryptography

noble-cryptography — high-security, easily auditable set of contained cryptographic libraries and tools.

• Zero or minimal dependencies
• Highly readable TypeScript / JS code
• PGP-signed releases and transparent NPM builds with provenance
• Check out homepage & all libraries: ciphers, curves, hashes, post-quantum, 5KB secp256k1 / ed25519

Usage

npm install @noble/ed25519

deno add jsr:@noble/ed25519

deno doc jsr:@noble/ed25519 # command-line documentation

We support all major platforms and runtimes. For node.js <= 18 and React Native, additional polyfills are needed: see below.

import * as ed from '@noble/ed25519';
(async () => {
  const { secretKey, publicKey } = await ed.keygenAsync();
  // const publicKey = await ed.getPublicKeyAsync(secretKey);
  const message = new TextEncoder().encode('hello noble');
  const signature = await ed.signAsync(message, secretKey);
  const isValid = await ed.verifyAsync(signature, message, publicKey);
})();

Enabling synchronous methods

Only async methods are available by default, to keep the library dependency-free. To enable sync methods:

import { sha512 } from '@noble/hashes/sha2.js';
ed.etc.sha512 = sha512;
// Sync methods can be used now:
const { secretKey, publicKey } = ed.keygen();
// const publicKey = ed.getPublicKey(secretKey);
const sig = ed.sign(msg, secretKey);
const isValid = ed.verify(sig, msg, publicKey);

React Native: polyfill getRandomValues and sha512

import 'react-native-get-random-values';
import { sha512 } from '@noble/hashes/sha2.js';
ed.etc.sha512 = sha512;
ed.etc.sha512Async = (m: Uint8Array) => Promise.resolve(sha512(m));

API

There are 4 main methods, which accept Uint8Array-s:

• keygen() and keygenAsync()
• getPublicKey(secretKey) and getPublicKeyAsync(secretKey)
• sign(message, secretKey) and signAsync(message, secretKey)
• verify(signature, message, publicKey) and verifyAsync(signature, message, publicKey)

keygen

import * as ed from '@noble/ed25519';
(async () => {
  const keys = ed.keygen(); // needs ed.hashes.sha512
  const { secretKey, publicKey } = keys
  const keysA = await ed.keygenAsync();
})();

getPublicKey

import * as ed from '@noble/ed25519';
(async () => {
  const pubKey = ed.getPublicKey(secretKeyA); // needs ed.hashes.sha512
  const pubKeyA = await ed.getPublicKeyAsync(secretKeyA);
  const pubKeyPoint = ed.Point.fromBytes(pubKeyB);
  const pubKeyExtended = ed.utils.getExtendedPublicKey(secretKeyA);
})();

Generates 32-byte public key from 32-byte private key.

• Some libraries have 64-byte private keys - those are just priv+pub concatenated
• Use ExtendedPoint.fromHex(publicKey) if you want to convert hex / bytes into Point. It will use decompression algorithm 5.1.3 of RFC 8032.
• Use utils.getExtendedPublicKey if you need full SHA512 hash of seed

sign

import * as ed from '@noble/ed25519';
(async () => {
  const { secretKey, publicKey } = ed.keygen();
  const message = new TextEncoder().encode('hello noble');
  const signature = ed.sign(message, secretKey);
  const signatureA = await ed.signAsync(message, secretKey);
})();

Generates deterministic EdDSA signature. message would be hashed by ed25519 internally. For prehashed ed25519ph, switch to noble-curves.

verify

import * as ed from '@noble/ed25519';
(async () => {
  const { secretKey, publicKey } = ed.keygen();
  const message = new TextEncoder().encode('hello noble');
  const signature = ed.sign(message, secretKey);
  const isValid = ed.verify(signature, message, pubKey);

  const isValidFips = ed.verify(signature, message, pubKey, { zip215: false });
  const isValidA = await ed.verifyAsync(signature, message, pubKey);
})();

Verifies EdDSA signature. Has SUF-CMA (strong unforgeability under chosen message attacks). By default, follows ZIP215 ¹ and can be used in consensus-critical apps ². zip215: false option switches verification criteria to strict RFC8032 / FIPS 186-5 and provides non-repudiation with SBS (Strongly Binding Signatures) ³.

utils

A bunch of useful utilities are also exposed:

import * as ed from '@noble/ed25519';
const { bytesToHex, hexToBytes, concatBytes, mod, invert, randomBytes } = ed.etc;
const { getExtendedPublicKey, getExtendedPublicKeyAsync, randomSecretKey } = ed.utils;
const { Point } = ed;
console.log(Point.CURVE(), Point.BASE);
/*
class Point {
  static BASE: Point;
  static ZERO: Point;
  readonly X: bigint;
  readonly Y: bigint;
  readonly Z: bigint;
  readonly T: bigint;
  constructor(X: bigint, Y: bigint, Z: bigint, T: bigint);
  static CURVE(): EdwardsOpts;
  static fromAffine(p: AffinePoint): Point;
  static fromBytes(hex: Bytes, zip215?: boolean): Point;
  static fromHex(hex: string, zip215?: boolean): Point;
  get x(): bigint;
  get y(): bigint;
  assertValidity(): this;
  equals(other: Point): boolean;
  is0(): boolean;
  negate(): Point;
  double(): Point;
  add(other: Point): Point;
  subtract(other: Point): Point;
  multiply(n: bigint, safe?: boolean): Point;
  multiplyUnsafe(scalar: bigint): Point;
  toAffine(): AffinePoint;
  toBytes(): Bytes;
  toHex(): string;
  clearCofactor(): Point;
  isSmallOrder(): boolean;
  isTorsionFree(): boolean;
}
*/

Security

The module is production-ready.

We cross-test against sister project noble-curves, which was audited and provides improved security.

• The current version has not been independently audited. It is a rewrite of v1, which has been audited by cure53 in Feb 2022: PDF.
• It's being fuzzed in a separate repository

If you see anything unusual: investigate and report.

Constant-timeness

We're targetting algorithmic constant time. JIT-compiler and Garbage Collector make "constant time" extremely hard to achieve timing attack resistance in a scripting language. Which means any other JS library can't have constant-timeness. Even statically typed Rust, a language without GC, makes it harder to achieve constant-time for some cases. If your goal is absolute security, don't use any JS lib — including bindings to native ones. Use low-level libraries & languages.

Supply chain security

• Commits are signed with PGP keys, to prevent forgery. Make sure to verify commit signatures
• Releases are transparent and built on GitHub CI. Check out attested checksums of single-file builds and provenance logs
• Rare releasing is followed to ensure less re-audit need for end-users
• Dependencies are minimized and locked-down: any dependency could get hacked and users will be downloading malware with every install.
  • We make sure to use as few dependencies as possible
  • Automatic dep updates are prevented by locking-down version ranges; diffs are checked with npm-diff
• Dev Dependencies are disabled for end-users; they are only used to develop / build the source code

For this package, there are 0 dependencies; and a few dev dependencies:

• noble-hashes provides cryptographic hashing functionality
• micro-bmark, micro-should and jsbt are used for benchmarking / testing / build tooling and developed by the same author
• prettier, fast-check and typescript are used for code quality / test generation / ts compilation. It's hard to audit their source code thoroughly and fully because of their size

Randomness

We're deferring to built-in crypto.getRandomValues which is considered cryptographically secure (CSPRNG).

In the past, browsers had bugs that made it weak: it may happen again. Implementing a userspace CSPRNG to get resilient to the weakness is even worse: there is no reliable userspace source of quality entropy.

Quantum computers

Cryptographically relevant quantum computer, if built, will allow to break elliptic curve cryptography (both ECDSA / EdDSA & ECDH) using Shor's algorithm.

Consider switching to newer / hybrid algorithms, such as SPHINCS+. They are available in noble-post-quantum.

NIST prohibits classical cryptography (RSA, DSA, ECDSA, ECDH) after 2035. Australian ASD prohibits it after 2030.

Speed

npm run bench

Benchmarks measured with Apple M4.

init 11ms
keygen x 11,253 ops/sec @ 88μs/op
sign x 5,891 ops/sec @ 169μs/op
verify x 1,281 ops/sec @ 780μs/op

keygenAsync x 10,205 ops/sec @ 97μs/op
signAsync x 4,985 ops/sec @ 200μs/op
verifyAsync x 1,286 ops/sec @ 777μs/op

Point.fromBytes x 22,811 ops/sec @ 43μs/op

Compare to alternative implementations:

[email protected] getPublicKey x 1,808 ops/sec @ 552μs/op ± 1.64%
[email protected] sign x 651 ops/sec @ 1ms/op
[email protected] getPublicKey x 640 ops/sec @ 1ms/op ± 1.59%
sodium-native#sign x 83,654 ops/sec @ 11μs/op

Upgrading

noble-ed25519 v2 features improved security and smaller attack surface. The goal of v2 is to provide minimum possible JS library which is safe and fast.

That means the library was reduced 4x, to just over 300 lines. In order to achieve the goal, some features were moved to noble-curves, which is even safer and faster drop-in replacement library with same API. Switch to curves if you intend to keep using these features:

• x25519 / curve25519 / getSharedSecret
• ristretto255 / RistrettoPoint
• Using utils.precompute() for non-base point
• Support for environments which don't support bigint literals
• Common.js support
• Support for node.js 18 and older without shim

Other changes for upgrading from @noble/ed25519 1.7 to 2.0:

• Methods are now sync by default; use getPublicKeyAsync, signAsync, verifyAsync for async versions
• bigint is no longer allowed in getPublicKey, sign, verify. Reason: ed25519 is LE, can lead to bugs
• Point (2d xy) has been changed to ExtendedPoint (xyzt)
• Signature was removed: just use raw bytes or hex now
• utils were split into utils (same api as in noble-curves) and etc (sha512Sync and others)

Contributing & testing

• npm install && npm run build && npm test will build the code and run tests.
• npm run bench will run benchmarks, which may need their deps first (npm run bench:install)
• npm run build:release will build single file

Check out github.com/paulmillr/guidelines for general coding practices and rules.

See paulmillr.com/noble for useful resources, articles, documentation and demos related to the library.

License

MIT (c) 2019 Paul Miller (https://paulmillr.com), see LICENSE file.

Footnotes

1. https://zips.z.cash/zip-0215 ↩

2. https://hdevalence.ca/blog/2020-10-04-its-25519am ↩

3. https://eprint.iacr.org/2020/1244 ↩