JavaScript Shamir Secret Sharing

A JavaScript library for Shamir Secret Sharing.

Compiling

Running GNU make will no arguments will generate jsss.js, perform all tests and minify to jsss.min.js using UglifyJS.

$ make

To only generate the human readable jsss.js, use:

$ make jsss.js

An to perform tests without minifying:

$ make test

Using

Include jsss.js or jsss.min.js in your code. For an HTML file:

<script src="jsss.js" type="text/javascript" charset="utf-8"></script>

Generating Shares

SecretSharing#generate takes the data (a number, BigInteger, or any String that BigInteger can parse), number of shares (int) and threshold (int):

SecretSharing.generate("0xf87db6f54", 10, 7);

The call will split the data into pieces <= 2^16, and return dictionary of the form:

{
  data: [piece_0, piece_1,...],
  shares: [[share0_0, share0_1,...], [share1_0, share1_1,...],...]
}

The elements in the data array are BigIntegers, as are the sub-elements in each of the arrays in the shares array.

Reconstructing Data

To reconstruct the original data, pass to SecretSharing#solve a shares array of the same form returned from SecretSharing#generate (except it may contain as few as threshold shares), the threshold (int) and optionally an outputBase (int representing the radix of the String returned, defaults to 10):

var shares = [[share0_0, share0_1,...], [share1_0, share1_1,...],...];
SecretSharing.solve(shares, 7, 16);
> "F87DB6F54"

This will return a String representing the original data using the radix passed int the outputBase variable (default 10).