kls-signatures

kls-signatures

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 Chik Network's BLS lib. We also have typings, so you can use it with TypeScript too!

$3

``bash
npm i kls-signatures --save # or yarn add kls-signatures
`

$3


`javascript
var loadBls = require("kls-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
`

$3

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

console.log(BLS.Util.hex_str(skBytes));
console.log(BLS.Util.hex_str(pkBytes));
console.log(BLS.Util.hex_str(signatureBytes));

`

$3

`javascript
var skc = BLS.PrivateKey.from_bytes(skBytes, false);
var pk = BLS.G1Element.from_bytes(pkBytes);

var signature = BLS.G2Element.from_bytes(signatureBytes);
`

$3


`javascript
// 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

`

$3

`javascript
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
`

$3

`javascript

// 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
`

$3


`javascript
// 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.

`javascript
sk.delete();
// ...
pk.delete();
// ...
sig1.delete();
// ...
`

$3

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.


$3


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
`bash
npm test
``