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    0.2.1-beta.3 • Public • Published


    JavaScript library that implements BLS signatures with aggregation as in Boneh, Drijvers, Neven 2018, using the relic toolkit for cryptographic primitives (pairings, EC, hashing).

    This library is a JavaScript port of the Chia Network's BLS lib. We also have typings, so you can use it with TypeScript too!


    npm i bls-signatures --save # or yarn add bls-signatures

    Creating keys and signatures

      var loadBls = require("bls-signatures");
      var BLS = await loadBls();
      var seed = Uint8Array.from([
        0,  50, 6,  244, 24,  199, 1,  25,  52,  88,  192,
        19, 18, 12, 89,  6,   220, 18, 102, 58,  209, 82,
        12, 62, 89, 110, 182, 9,   44, 20,  254, 22
      var sk = BLS.AugSchemeMPL.key_gen(seed);
      var pk = sk.get_g1();
      var message = Uint8Array.from([1,2,3,4,5]);
      var signature = BLS.AugSchemeMPL.sign(sk, message);
      let ok = BLS.AugSchemeMPL.verify(pk, message, signature);
      console.log(ok); // true

    Serializing keys and signatures to bytes

      var skBytes = sk.serialize();
      var pkBytes = pk.serialize();
      var signatureBytes = signature.serialize();

    Loading keys and signatures from bytes

      var skc = BLS.PrivateKey.from_bytes(skBytes, false);
      var pk = BLS.G1Element.from_bytes(pkBytes);
      var signature = BLS.G2Element.from_bytes(signatureBytes);

    Create aggregate signatures

      // Generate some more private keys
      seed[0] = 1;
      var sk1 = BLS.AugSchemeMPL.key_gen(seed);
      seed[0] = 2;
      var sk2 = BLS.AugSchemeMPL.key_gen(seed);
      var message2 = Uint8Array.from([1,2,3,4,5,6,7]);
      // Generate first sig
      var pk1 = sk1.get_g1();
      var sig1 = BLS.AugSchemeMPL.sign(sk1, message);
      // Generate second sig
      var pk2 = sk2.get_g1();
      var sig2 = BLS.AugSchemeMPL.sign(sk2, message2);
      // Signatures can be non-interactively combined by anyone
      var aggSig = BLS.AugSchemeMPL.aggregate([sig1, sig2]);
      ok = BLS.AugSchemeMPL.aggregate_verify([pk1, pk2], [message, message2], aggSig);
      console.log(ok); // true

    Arbitrary trees of aggregates

      seed[0] = 3;
      var sk3 = BLS.AugSchemeMPL.key_gen(seed);
      var pk3 = sk3.get_g1();
      var message3 = Uint8Array.from([100, 2, 254, 88, 90, 45, 23]);
      var sig3 = BLS.AugSchemeMPL.sign(sk3, message3);
      var aggSigFinal = BLS.AugSchemeMPL.aggregate([aggSig, sig3]);
      ok = BLS.AugSchemeMPL.aggregate_verify([pk1, pk2, pk3], [message, message2, message3], aggSigFinal);
      console.log(ok); // true

    Very fast verification with Proof of Possession scheme

      // If the same message is signed, you can use Proof of Posession (PopScheme) for efficiency
      // A proof of possession MUST be passed around with the PK to ensure security.
      var popSig1 = BLS.PopSchemeMPL.sign(sk1, message);
      var popSig2 = BLS.PopSchemeMPL.sign(sk2, message);
      var popSig3 = BLS.PopSchemeMPL.sign(sk3, message);
      var pop1 = BLS.PopSchemeMPL.pop_prove(sk1);
      var pop2 = BLS.PopSchemeMPL.pop_prove(sk2);
      var pop3 = BLS.PopSchemeMPL.pop_prove(sk3);
      ok = BLS.PopSchemeMPL.pop_verify(pk1, pop1);
      console.log(ok); // true
      ok = BLS.PopSchemeMPL.pop_verify(pk2, pop2);
      console.log(ok); // true
      ok = BLS.PopSchemeMPL.pop_verify(pk3, pop3);
      console.log(ok); // true
      var popSigAgg = BLS.PopSchemeMPL.aggregate([popSig1, popSig2, popSig3]);
      ok = BLS.PopSchemeMPL.fast_aggregate_verify([pk1, pk2, pk3], message, popSigAgg);
      console.log(ok); // true
      // Aggregate public key, indistinguishable from a single public key
      var popAggPk = pk1.add(pk2).add(pk3);
      ok = BLS.PopSchemeMPL.verify(popAggPk, message, popSigAgg);
      console.log(ok); // true
      // Aggregate private keys
      var aggSk = BLS.PrivateKey.aggregate([sk1, sk2, sk3]);
      ok = (BLS.PopSchemeMPL.sign(aggSk, message).equal_to(popSigAgg));
      console.log(ok); // true

    HD keys using EIP-2333

      // You can derive 'child' keys from any key, to create arbitrary trees. 4 byte indeces are used.
      // Hardened (more secure, but no parent pk -> child pk)
      var masterSk = BLS.AugSchemeMPL.key_gen(seed);
      var child = BLS.AugSchemeMPL.derive_child_sk(masterSk, 152);
      var grandChild = BLS.AugSchemeMPL.derive_child_sk(child, 952);
      // Unhardened (less secure, but can go from parent pk -> child pk), BIP32 style
      var masterPk = masterSk.get_g1();
      var childU = BLS.AugSchemeMPL.derive_child_sk_unhardened(masterSk, 22);
      var grandchildU = BLS.AugSchemeMPL.derive_child_sk_unhardened(childU, 0);
      var childUPk = BLS.AugSchemeMPL.derive_child_pk_unhardened(masterPk, 22);
      var grandchildUPk = BLS.AugSchemeMPL.derive_child_pk_unhardened(childUPk, 0);
      ok = (grandchildUPk.equal_to(grandchildU.get_g1()));
      console.log(ok); // true

    Please refer to the library's typings for detailed API information. Use cases can be found in the original lib's readme.

    Important note on usage: Since this library is a WebAssembly port of the c++ library, JavaScript's automatic memory management isn't available. Please, delete all objects manually if they are not needed anymore by calling the delete method on them, as shown in the example below.

      // ...
      // ...
      // ...


    Building requires Node.js (with npm) and Emscripten to be installed. The build process is the same as for the c++ lib, with one additional step: pass the Emscripten toolchain file as an option to CMake. From the project root directory, run:

    #git submodule update --init --recursive
    mkdir js_build
    cd js_build
    cmake ../ -DCMAKE_TOOLCHAIN_FILE={path_to_your_emscripten_installation}/emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake
    cmake --build . --

    Run the build after any changes to the library, including readme and tests, as the library will be deployed from the build directory, and the build system copies all the files from the source dir.

    Run tests

    Tests are run in node.js and Firefox, therefore you need to install node.js and Firefox. To run tests, build the library, then go to the js_bindings folder in the build directory and run

    npm test


    npm i @aguycalled/bls-signatures

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