Digest.scala

def digest(in: InputStream, md: MessageDigest): Array[Byte] = {
  val buffer = new Array[Byte](0x1000)
  @tailrec
  def loop(count: Int): Array[Byte] = {
    if (count == -1)
      md.digest
    else {
      md.update(buffer, 0, count)
      loop(in read buffer)
    }
  }
  try loop(in read buffer) finally md.reset()
}