Comparison of strings in a time attack safe way

safe_equals.scala

def safeEquals(a: String, b: String) = {
  val a_bytes = a.getBytes
  val b_bytes = b.getBytes
  if (a_bytes.length != b_bytes.length) {
    false
  }
  else {
    a_bytes.zip(b_bytes).foldLeft(0){ (acc, t) => acc + (t._1 ^ t._2) } == 0
  }
}