randombytes.js

const test = require('brittle')
const sodium = require('..')

test('constants', function (t) {
  t.alike(typeof sodium.randombytes_SEEDBYTES, 'number', 'randombytes_SEEDBYTES is number')
})

test('randombytes_random', function (t) {
  for (let i = 0; i < 1e6; i++) {
    const n = sodium.randombytes_random()
    if (n > 0xffffffff || n < 0) t.fail()
  }
})

test('randombytes_uniform', function (t) {
  const p = 5381
  for (let i = 0; i < 1e6; i++) {
    const n = sodium.randombytes_uniform(5381)
    if (n >= p || n < 0) t.fail()
  }
})

test('randombytes_buf', function (t) {
  let buf = null

  buf = Buffer.alloc(10)
  sodium.randombytes_buf(buf)
  t.not(buf, Buffer.alloc(10), 'not blank')

  buf = Buffer.alloc(1024)
  sodium.randombytes_buf(buf)
  t.not(buf, Buffer.alloc(1024), 'large not blank')
})

test('randombytes_deterministic', function (t) {
  const seed1 = Buffer.allocUnsafe(sodium.randombytes_SEEDBYTES)
  const seed2 = Buffer.allocUnsafe(sodium.randombytes_SEEDBYTES)
  const buf1 = Buffer.alloc(10)
  const buf2 = Buffer.alloc(10)

  for (let i = 0; i < 1e6; i++) {
    sodium.randombytes_buf(seed1)
    sodium.randombytes_buf(seed2)

    sodium.randombytes_buf_deterministic(buf1, seed1)
    sodium.randombytes_buf_deterministic(buf2, seed1)
    if (!buf1.equals(buf2)) t.fail('should equal')

    sodium.randombytes_buf_deterministic(buf1, seed1)
    sodium.randombytes_buf_deterministic(buf2, seed2)
    if (buf1.equals(buf2)) t.fail('should not equal')

    sodium.randombytes_buf_deterministic(buf1, seed2)
    sodium.randombytes_buf_deterministic(buf2, seed1)
    if (buf1.equals(buf2)) t.fail('should not equal')

    sodium.randombytes_buf_deterministic(buf1, seed2)
    sodium.randombytes_buf_deterministic(buf2, seed2)
    if (!buf1.equals(buf2)) t.fail('should equal')
  }
})

test.skip('Various test cases', function (t) {
  sodium.randombytes_buf(Buffer.alloc(0))
  sodium.randombytes_buf(new Uint8Array(16))

  t.throws(function () {
    sodium.randombytes_buf([])
  })

  t.end()
})

test('Generates random bytes', function (t) {
  const bufConst = Buffer.alloc(64)
  sodium.randombytes_buf(bufConst)

  const buf1 = Buffer.alloc(64)
  for (let i = 0; i < 1e4; i++) {
    sodium.randombytes_buf(buf1)
    if (Buffer.compare(buf1, bufConst) === 0) {
      t.fail('Constant buffer should not be equal')
      t.end()
      return
    }
  }

  t.pass('Generated unique buffers')
  t.end()
})

test('Exceed quota', function (t) {
  const buf = Buffer.alloc(1 << 17)
  sodium.randombytes_buf(buf)

  const scores = new Array(256)
  scores.fill(0)

  for (const b of buf) {
    scores[b]++
  }

  scores
    .map(cnt => cnt / 256)
    .forEach(cnt => {
      if (cnt < 1 && cnt > 3) t.fail('Statistically unreasonable')
    })

  t.end()
})