bls_dart

BLS12-381 min_pk signature operations for Dart & Flutter, powered by blst via flutter_rust_bridge.

Uses the DST string BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_, matching Sui Move's bls12381_min_pk_verify.

Web is not supported because blst is a native C/assembly library.

Installation

dependencies:
  bls_dart: ^0.1.0

Usage

import 'package:bls_dart/bls_dart.dart';

void main() async {
  // Initialize the Rust runtime once before calling any BLS function.
  await RustLib.init();

  // Verify a single signature.
  final valid = bls12381MinPkVerify(
    sigBytes: signature,  // 96-byte compressed G2 signature
    pkBytes: publicKey,   // 48-byte compressed G1 public key
    msg: message,         // arbitrary-length message bytes
  );

  // Aggregate multiple signatures into one.
  final aggSig = bls12381MinPkAggregate(
    sigsBytes: [sig1, sig2, sig3], // list of 96-byte signatures
  );
  // Returns 96-byte aggregate signature, or empty Uint8List on error.

  // Verify an aggregate signature (all signers signed the same message).
  final aggValid = bls12381MinPkVerifyAggregate(
    pksBytes: [pk1, pk2, pk3],  // list of 48-byte public keys
    msg: message,
    aggSigBytes: aggSig,        // 96-byte aggregate signature
  );
}

API reference

bls12381MinPkVerify

bool bls12381MinPkVerify({
  required List<int> sigBytes,   // 96-byte compressed G2 signature
  required List<int> pkBytes,    // 48-byte compressed G1 public key
  required List<int> msg,        // message bytes
})

Returns true when the signature is valid, false otherwise (including malformed inputs).

bls12381MinPkAggregate

Uint8List bls12381MinPkAggregate({
  required List<Uint8List> sigsBytes, // list of 96-byte signatures
})

Returns the 96-byte aggregate signature, or an empty Uint8List on error (empty list, malformed input).

bls12381MinPkVerifyAggregate

bool bls12381MinPkVerifyAggregate({
  required List<Uint8List> pksBytes,   // list of 48-byte public keys
  required List<int> msg,              // shared message
  required List<int> aggSigBytes,      // 96-byte aggregate signature
})

Returns true when the aggregate signature is valid, false otherwise.

Key sizes

Type	Size (bytes)	Curve point
Public key	48	G1
Signature	96	G2
Aggregate signature	96	G2

How it works

bls_dart wraps the blst C library (v0.3) through a thin Rust shim compiled via flutter_rust_bridge. The native library is built automatically by Cargokit when you run flutter build or flutter test.

All three functions are synchronous after the one-time RustLib.init() call — no Future overhead per operation.

License

MIT — see LICENSE.

Publishing (maintainers)

bls_dart uses a two-package publish flow because rust_lib_bls_dart (the cargokit native build plugin) must be on pub.dev first.

Local development uses a gitignored pubspec_overrides.yaml that redirects to path: rust_builder. The committed pubspec.yaml always declares the hosted dep — so no file edits are needed before publishing.

# Step 1 — publish the native builder sub-package
cd rust_builder && flutter pub publish

# Step 2 — publish the main package
cd .. && flutter pub publish