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 specified), 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)

AVAILABILITY


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

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