Description

   The encrypt function encrypts a string using the key generated by
   the setkey function.

   The first argument to encrypt is a character array of length 64
   containing 0s and 1s. The argument array is modified in place
   to a similar array representing the bits of the argument after
   having been subjected to the DES algorithm using the key set by
   setkey.

   The second argument, edflag, determines whether the first
   argument is encrypted or decrypted: if edflag is 0, the first
   argument array is encrypted; if nonzero, it is decrypted.

   No value is returned.

   See also crypt and setkey.