22 May 2020   7:55:25.999 PM

ATBASH_TEST
  FORTRAN90 version
  ATBASH_ENCRYPT encrypts a plain text using the Atbash
  substitution cipher.

TEST01
  Apply ATBASH to a short phrase.

PLAIN:   "A man, a plan, a canal - Panama!"
CRYPT:   "Z nzm, z kozm, z xzmzo - Kzmznz!"
DECRYPT: "A man, a plan, a canal - Panama!"

TEST02
  Apply ATBASH to a longer phrase.

PLAIN:   "There are a thousand hacking at the branches of evil for every one who is striking at its root."
CRYPT:   "Gsviv ziv z gslfhzmw szxprmt zg gsv yizmxsvh lu vero uli vevib lmv dsl rh hgirprmt zg rgh illg."
DECRYPT: "There are a thousand hacking at the branches of evil for every one who is striking at its root."

ATBASH_TEST
  Normal end of execution.

22 May 2020   7:55:25.999 PM