MCOOKIE(1)          Linux Programmer's Manual          MCOOKIE(1)

NAME
       mcookie - generate magic cookies for xauth

SYNOPSIS
       mcookie [-v] [-f filename ]

DESCRIPTION
       mcookie  generates a 128-bit random hexadecimal number for
       use with the X authority system.  Typical usage:
              xauth add :0 . `mcookie`

       The "random" number generated is actually  the  output  of
       the  MD5  message  digest fed with various piece of random
       information: the current time, the process id, the  parent
       process id, the contents of an input file (if -f is speci-
       fied), and several bytes of information from the first  of
       the  following  devices  which  is  present:  /dev/random,
       /dev/urandom, files in /proc, /dev/audio.

BUGS
       The entropy in the generated  128-bit  is  probably  quite
       small (and, therefore, vulnerable to attack) unless a non-
       pseudorandom number generator is used  (e.g.,  /dev/random
       under Linux).

       It  is assumed that none of the devices opened will block.

FILES
       /dev/random
       /dev/urandom
       /dev/audio
       /proc/stat
       /proc/loadavg

SEE ALSO
       X(1), xauth(1), md5sum(1)

                        25 September 1995                       1