(let [kraw (kwork/genkey)
        jumbled-key (kwork/jumble kraw)
        index (io/file index-file)
        dump (io/file dump-file)
        index-f (io/file index-final)
        dump-f (io/file dump-final)
        tmp-index (java.io.File/createTempFile "ussa__11_" "90001__"
                                               (.getParentFile index))
        tmp-dump (java.io.File/createTempFile "ussa__11_" "90001__"
                                              (.getParentFile dump))]
    [(try
        (do
          (.createNewFile index-f)
          (.createNewFile dump-f)
          (.deleteOnExit index)
          (.deleteOnExit dump)
          (with-open [index-is (io/input-stream index)
                      tmpindex-os (io/output-stream tmp-index)]
            (.write tmpindex-os jumbled-key 0 (alength jumbled-key)) ;; write key
            (kwork/encf index-is tmpindex-os kraw) ;; write dump contents
            (.renameTo tmp-index index-f))
          (with-open [dump-is (io/input-stream dump)
                      tmpdump-os (io/output-stream tmp-dump)]
            (kwork/encf dump-is tmpdump-os kraw)
            (.renameTo tmp-dump dump-f)))
          )
     (catch Exception e (println (str "EXCEPTION " e))))]
    (do
      (System/gc)
      (.renameTo tmp-index index-f)
      (.renameTo tmp-dump dump-f))))