def secure_compare(a, b)
      return false unless a.bytesize == b.bytesize

      l = a.unpack("C*")

      r, i = 0, -1
      b.each_byte { |v| r |= v ^ l[i+=1] }
      r == 0
    end
def secure_compare(a, b)
      return false unless a.bytesize == b.bytesize

      l = a.unpack("C*")

      r, i = 0, -1
      b.each_byte { |v| r |= v ^ l[i+=1] }
      r == 0
    end
After the Rack implementation