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# mcookie - Unix, Linux Command

# 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)

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