mcookie



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 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  gen-
       erator 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)



                               25 September 1995                    MCOOKIE(1)

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