Provided by: util-linux_2.20.1-5.1ubuntu20_amd64 bug

NAME

       mcookie - generate magic cookies for xauth

SYNOPSIS

       mcookie [options]

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 pieces of random information: the current time, the process id, the parent process
       id, and optionally the contents of an input file. and several bytes  of  information  from
       the  first  of the following devices which is present: /dev/random, /dev/urandom, files in
       /proc, /dev/audio.

OPTIONS

       -f, --file=FILE
              Use file as a macig cookie seed. When file is defined as  `-'  character  input  is
              read from stdin.

       -v, --verbose
              Explain what is being done.

       -V, --version
              Output version information and exit.

       -h, --help
              Display this help and exit.

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)

AVAILABILITY

       The   mcookie   command   is  part  of  the  util-linux  package  and  is  available  from
       ftp://ftp.kernel.org/pub/linux/utils/util-linux/.