Voting cryptography lib

Install

Browser:

npm i @wavesenterprise/voting-crypto bn.js

NodeJS:

npm i @wavesenterprise/voting-crypto secp256k1

Usage

Browser:

// For browsers with BigInt support
import { makeEncryptedBulletin } from '@wavesenterprise/voting-crypto/browser'
// For browsers without BigInt support
import { makeEncryptedBulletin } from '@wavesenterprise/voting-crypto/browser-old'

const encrypted = makeEncryptedBulletin({
  mainKey: '024bfdeb94ed1ef7011342ff5d2f47d9f3526c147c5e145cb99d440b99f41979f6',
  weight: 1,
  bulletin: [[0, 1]],
  dimension: [[1, 1, 2]],
})

NodeJS:

Generating points:

import { preGeneratePoints } from '@wavesenterprise/voting-crypto/node'

const points = preGeneratePoints({ from: 0, to: 10_000 })

Generating keys:

import { generateKeys } from '@wavesenterprise/voting-crypto/node'

const d1keys = generateKeys()

Unblind keys:

import { unblindPublicKeys } from '@wavesenterprise/voting-crypto/node'

const pairs = [d1keys, d2keys, d3keys].map((keys) => ([keys.publicKeyOfCommit, keys.privateKeyOfCommit]))
const unblindedKeys = unblindPublicKeys(pairs)

Get poly coefficients:

import { getPolynomialCoefficients } from '@wavesenterprise/voting-crypto/node'

const k = 2
const coefficients1 = getPolynomialCoefficients(d1keys.privateKey, k)

Get exponents:

import { getPolynomialCoefficientsExponents } from '@wavesenterprise/voting-crypto/node'

const exponents1 = getPolynomialCoefficientsExponents(coefficients1)

Get encrypted shadows:

import { calculateEncryptedShadows } from '@wavesenterprise/voting-crypto/node'

const shadows1 = calculateEncryptedShadows(unblindedKeys, coefficients1)

Decrypt and check shadows:

import { decryptAndCheckShadows } from '@wavesenterprise/voting-crypto/node'

const idx = 0
const shadowsSum1 = decryptAndCheckShadows({
  privateKey: d1keys.privateKey,
  idx,
  encryptedShadows: [shadows1[idx], shadows2[idx], shadows3[idx]],
  exponents: [exponents1, exponents2, exponents3],
  unblindedPublicKeys: unblindedKeys,
})

Get mainkey:

import { calculateMainKey } from '@wavesenterprise/voting-crypto/node'

const pairs = [d1keys, d2keys, d3keys].map((keys) => ([keys.publicKeyOfCommit, keys.privateKeyOfCommit]))
const mainKey = calculateMainKey(pairs)

Encrypt bulletin:
pass true as a second arg to get raw bytes output

import { makeEncryptedBulletin } from '@wavesenterprise/voting-crypto/node'

const dimension: Dimension = [[1, 1, 3]]
const weight = 100
const encrypted = makeEncryptedBulletin({
  dimension,
  mainKey,
  bulletin: [[0, weight, 0]],
  weight,
})

Verify bulletins:
weight must be multiplied
encrypted accepts raw bytes or formatted as input

import { verifyBulletin } from '@wavesenterprise/voting-crypto/node'

const result = verifyBulletin(encrypted, mainKey, dimension, weight)

Add bulletins:

import { addBulletins } from '@wavesenterprise/voting-crypto/node'

const prev = null
const added0 = addBulletins(encrypted, prev)
const added = addBulletins(encrypted, added0)
const subtracted = addBulletins(encrypted, added)

Create partial decryption:

import { createPartialDecryption } from '@wavesenterprise/voting-crypto/node'

const decryprion1 = createPartialDecryption(added, shadowsSum1)

Calculate results:

const results = await calculateResult({
  indexes: [1, 3],
  totalWeight: weight,
  exponents: [exponents1, exponents2, exponents3],
  partialDecryptions: [decryprion1, decryprion2, decryprion3],
  sum: added, 
  mainKey,
})