dart_ssss

A Dart library that implements Shamir's Secret Sharing Scheme over GF(256).

Given a secret in bytes, this package can assist in splitting up the secret into n parts and would be able to reconstruct the secret in bytes given a t threshold.

I would highly recommend you look at the the wikipedia page above to learn about the workings of Shamir's Secret Sharing Scheme.

Getting Started

To use dart_ssss, add it to your dependencies in pubspec.yaml:

dependencies:
    dart_ssss: any

Then import the proper package:

import 'package:dart_ssss/dart_ssss.dart';

Usage

To generate shares / parts for a secret of bytes:

void main() {
    
    List<int> secretInByteValues = [...];
    
    SecretScheme ss = new SecretScheme(numberOfPartsToGenerate, thresholdForJoining);
    
    Map<int, List<int>> shares = ss.createShares(secretInByteValues);
    
    ...

To combine shares to regenerate a secret:

    List<int> recombinedSecretInBytes = ss.combineShares(shares);
}

Tests

To run tests on this package:

    pub run test

in the package directory.

Limitations / Caveats

Given that the package is implemented over GF(256), it means that the max number of shares / parts it can generate is 255. With that said, it is not advisable to generate 255 shares / parts as an adversary can forge a secret.

Shamir's Secret Sharing Scheme does not guarantee integrity, so if you are looking for something where you can verify shares or the resulting secret, this package is not for you.

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.