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/.

util-linux                                          June 2011                                         MCOOKIE(1)