shamirs-secret-sharing/table.js

A simple implementation of Shamir's Secret Sharing configured to use a finite field in GF(2^8) with 128 bit padding

import { PRIMITIVE_POLYNOMIAL, MAX_SHARES, BIT_SIZE, } from './constants.js'

export const zeroes = new Array(4 * BIT_SIZE).join('0')
export const logs = new Array(BIT_SIZE).fill(0)
export const exps = new Array(BIT_SIZE).fill(0)

for (let i = 0, x = 1; i < BIT_SIZE; ++i) {
  exps[i] = x
  logs[x] = i
  x = x << 1
  if (x >= BIT_SIZE) {
    x = x ^ PRIMITIVE_POLYNOMIAL
    x = x & MAX_SHARES
  }
}

export default {
  exps,
  logs,
  zeroes
}