misc-utils/mcookie.1

   1 .\" mcookie.1 --
   2 .\" Public Domain 1995 Rickard E. Faith (faith@cs.unc.edu)
   3 .TH MCOOKIE 1 "June 2011" "util-linux" "User Commands"
   4 .SH NAME
   5 mcookie \- generate magic cookies for xauth
   6 .SH SYNOPSIS
   7 .B mcookie
   8 [\fIoptions\fR]
   9 .SH DESCRIPTION
  10 .B mcookie
  11 generates a 128-bit random hexadecimal number for use with the X authority
  12 system.  Typical usage:
  13 .RS
  14 xauth add :0 . `mcookie`
  15 .RE
  16 .PP
  17 The "random" number generated is actually the output of the MD5 message
  18 digest fed with various pieces of random information: the current time, the
  19 process id, the parent process id, and optionally the contents of an input
  20 file. and several bytes of information from the first of the following
  21 devices which is present:
  22 .IR /dev/random ,
  23 .IR /dev/urandom ,
  24 files in
  25 .IR /proc ,
  26 .IR /dev/audio .
  27 .SH OPTIONS
  28 .TP
  29 \fB\-f\fR, \fB\-\-file\fR=\fIFILE\fR
  30 Use file as a macig cookie seed. When file is defined as `-' character
  31 input is read from stdin.
  32 .TP
  33 \fB\-v\fR, \fB\-\-verbose\fR
  34 Explain what is being done.
  35 .TP
  36 \fB\-V\fR, \fB\-\-version\fR
  37 Output version information and exit.
  38 .TP
  39 \fB\-h\fR, \fB\-\-help\fR
  40 Display this help and exit.
  41 .SH BUGS
  42 The entropy in the generated 128-bit is probably quite small (and,
  43 therefore, vulnerable to attack) unless a non-pseudorandom number generator
  44 is used (e.g.,
  45 .I /dev/random
  46 under Linux).
  47 .PP
  48 It is assumed that none of the devices opened will block.
  49 .SH FILES
  50 .I /dev/random
  51 .br
  52 .I /dev/urandom
  53 .br
  54 .I /dev/audio
  55 .br
  56 .I /proc/stat
  57 .br
  58 .I /proc/loadavg
  59 .SH "SEE ALSO"
  60 .BR X (1),
  61 .BR xauth (1),
  62 .BR md5sum (1)
  63 .SH AVAILABILITY
  64 The mcookie command is part of the util-linux package and is available from
  65 ftp://ftp.kernel.org/pub/linux/utils/util-linux/.