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7.1.1 • Public • Published


codecov ETH2.0_Spec_Version 1.0.0 ES Version Node Version

Javascript library for BLS (Boneh-Lynn-Shacham) signatures and signature aggregation, tailored for use in Eth2.


yarn add @chainsafe/bls

To use native bindings you must install peer dependency @chainsafe/blst

yarn add @chainsafe/bls @chainsafe/blst

By default, native bindings will be used if in NodeJS and they are installed. A WASM implementation ("herumi") is used as a fallback in case any error occurs.

import {SecretKey, secretKeyToPublicKey, sign, verify} from "@chainsafe/bls";

(async () => {
  await init("herumi");

  // class-based interface
  const secretKey = SecretKey.fromKeygen();
  const publicKey = secretKey.toPublicKey();
  const message = new Uint8Array(32);

  const signature = secretKey.sign(message);
  console.log("Is valid: ", signature.verify(publicKey, message));

  // functional interface
  const sk = secretKey.toBytes();
  const pk = secretKeyToPublicKey(sk);
  const sig = sign(sk, message);
  console.log("Is valid: ", verify(pk, message, sig));


If you are in the browser, import from /herumi to explicitly import the WASM version

import bls from "@chainsafe/bls/herumi";

Native bindings only

If you are in NodeJS, import from /blst-native to explicitly import the native bindings. Also install peer dependency @chainsafe/blst which has the native bindings

yarn add @chainsafe/bls @chainsafe/blst
import bls from "@chainsafe/bls/blst-native";

Get implementation at runtime

If you need to get a bls implementation at runtime, import from /getImplementation.

import {getImplementation} from "@chainsafe/bls/getImplementation";

const bls = await getImplementation("herumi");

Switchable singleton

If you need a singleton that is switchable at runtime (the default behavior in <=v6), import from /switchable.

import bls, {init} from "@chainsafe/bls/switchable";

// here `bls` is uninitialized
await init("herumi");
// here `bls` is initialized
// now other modules can `import bls from "@chainsafe/bls/switchable"` and it will be initialized

The API is identical for all implementations.


Results are in ops/sec (x times slower), where x times slower = times slower than fastest implementation (blst).

Function - ops/sec blst herumi noble
verify 326.38 47.674 (x7) 17.906 (x18)
verifyAggregate (30) 453.29 51.151 (x9) 18.372 (x25)
verifyMultiple (30) 34.497 3.5233 (x10) 2.0286 (x17)
verifyMultipleSignatures (30) 26.381 3.1633 (x8) -
aggregate (pubkeys, 30) 15686 2898.9 (x5) 1875.0 (x8)
aggregate (sigs, 30) 6373.4 1033.0 (x6) 526.25 (x12)
sign 925.49 108.81 (x9) 10.246 (x90)

* blst and herumi performed 100 runs each, noble 10 runs.

Results from CI run https://github.com/ChainSafe/bls/runs/1513710175?check_suite_focus=true#step:12:13

Spec versioning

Version Bls spec hash-to-curve version
5.x.x draft #9
2.x.x draft #7
1.x.x draft #6
0.3.x initial version


test vectors




npm i @chainsafe/bls

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