When OpenSSL generates keys you'll always see a series of periods/dots (.) and pluses (+).

openssl dhparam -text -noout -outform PEM -5 2048


  ............+........+...................................................................................................................................................................+..........................+......+......+..........................................................................................................................................................................................+....................................................................................................................................................................+..............................................................................................................................+.............................................................................................................................+.......+............................................................................................................................+..+.......................................................+....................................................................................................................................+..................................+...........................................................+...........................................................................................................................................................................................................................................................................................................+.+...................................................................................................+................................................................................................+.....+....+.................+.......................................................+.............................................................................................+...............................................................................................................................................................+................+....................................................+....................................................................................+...........................................................................................................................................................................................................................................................................................................................................................................................................................................................+.......................................................................+......................................................................................................................................................................................................................+............................................................+...........................................................................+.............................................................+.......................................+....................................................................................+............................................................................................................................................................+..................+...........................................................+.......................................................................................+.....................................................................................................................+...............................................................................................+.............................+.....................................+..................+...........................................................................................................+...........................................+...+.............................................................................................................................................................................+....................................................+............+.............................................................................................................................................................+.....................................+.....+.........................+...........................................................+..........................................................................................+............................................................................................................................................+.................................................+..........................................................................................+.......................+..........................................................................................+......................................................................................................................................................................................+.................................................................................................+...........................................................+.............................................................................................................................+......................+.............................................................................................................................+........................................+..........................................................................+..............................................+............................................................+...+.................................................................................+............................................+................+..........+.........+.....................................+...........................................+..........................................................................................................+........................................................................................................................................................................................................................................................................................................................................................+...........................................................................+..........................+..................................+...........................................................+................................................................................+..+.........................+..................................................................................................................................+........................+.......................................................+..........................................................................................+..........................................+.+...................................................+............................................................................................................+.........................................................................................................................................................................................................+.................................................................................................+....................+.......................................................................................................................+...............................+............................................................................+...............................+....................................................................................................................................................................................................................................................................................................................................................................................................................................+.........................................+.....................+........................................................................+.....................+..........+...............................................................+...........+...............................+....++*++*


What do they mean?

When computing DHPARAM you will get these as the output while computing Diffie Hellman parameters:

. : A potential prime number was generated.
+ : Number is being tested for primality.
* : A prime number was found.


References:


source code: dh_cb function in dhparam.c
man page: dhparam

