MCOOKIE(1) User Commands MCOOKIE(1)
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 gener-
ator 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)