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 pieces 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 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/.

								 25 September 1995							MCOOKIE(1)