bls

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

Usage

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 bls from "@chainsafe/bls";

(async () => {
    // class-based interface
    const secretKey = bls.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 = bls.secretKeyToPublicKey(sk);
    const sig = bls.sign(sk, message);
    console.log("Is valid: ", bls.verify(pk, message, sig));
})();

Browser

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.

Benchmarks

• blst: src/blst-native (node.js-only, bindings to C via node-gyp)
• herumi: src/herumi (node.js & browser, wasm)
• noble: noble-bls12-381 (node.js & browser, pure JS)

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

spec

test vectors

License

Apache-2.0