message: Assert input and out
diff: @@ -211,12 +211,14 @@ function Blake2b (outlen, key, salt, personal) {
  }
  Blake2b.prototype.update = function (input) {
  + assert(input != null, 'input must be Uint8Array or Buffer')
  blake2bUpdate(this, input)
  return this
  }
  Blake2b.prototype.digest = function (out) {
  var buf = (!out || out === 'binary' || out === 'hex') ? new Uint8Array(this.outlen) : out
  + assert(buf.length >= this.outlen, 'out must have at least outlen bytes of space')
  blake2bFinal(this, buf)
  if (out === 'hex') return hexSlice(buf)
  return buf
  