For some unknown reason fopen("con", "w") is the
only way to make this work. Using "r+" and "w+"
causes the fopen call to fail and the fallback
(using stdin) doesn't work because writing to stdin
fails.
like des_read_password and friends (backward compatibility functions
using this new API are provided). The purpose is to remove prompting
functions from the DES code section as well as provide for prompting
through dialog boxes in a window system and the like.