Table of Contentsmcookie - generate magic cookies for xauth mcookie [-v] [-f filename ] 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/urandom, /dev/random, /dev/audio. Other files in /proc may be used as a last resort.
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.
/dev/random
/dev/urandom
/dev/audio
/proc/stat
/proc/loadavg X(1), xauth(1), md5sum(1)
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