Pad(1) Free Speech Utilities Pad(1)NAME
PAD - Random pad utility
SYNOPSIS
Pad [OPTIONS] [infile] [-o outfile]
DESCRIPTION
PAD is a small command-line utility to separate one file into two, each
indistinguishable from white noise, and put them back together into the
original.
OPTIONS
Pad accepts the following options:
-r [num]
Pad will XOR in [num] pads generated from random data. If this
is omitted, pad will use either 1 or 0 random pads, depending
on if there is only one input file or more than one, respec‐
tively.
-s [size]
The output data will be [size] bytes. If this is less than the
smallest input file, the output will be clipped to match, if it
is larger, random data will be appended to the end. [size] can
be any value in bytes, or a string such as "2M", or "140K".
-o [outfile]
The result of all the XOR operations will be stored in this
file. If [output] is omitted, pad will name the file according
to its MD5-sum, along with the rest of the random pads.
-h
Displays usage information.
REQUIREMENTS
Aside from the usual (x86/unix, GNU C Compiler), you need OpenSSL
(http://www.openssl.org)
NOTES
Any number of input files may be specified, but if they are unequal in
size, pad will only process the number of bytes in the smallest file
unless otherwise specified by the -s flag.
Examples:
pad myfile.txt
You now have pad-md5-xxxxxx.dat and pad-md5-yyyyyy.dat.
pad pad-md5-xxxxxx.dat pad-md5-yyyyyy.dat -o output-file
You now have output-file, which is identical to the original
myfile.txt, built from your two pad files.
Let's use David Madore's method of distributed free speech:
<download pad-md5-aaaaaaa through ddddddd.dat from a pad repository>
pad-s 128k myfile.txt pad-md5-*.dat Wrote pad-md5-eeeeeee.dat
Now you upload pad-md5-eeeeeee.dat to some pad repository, and tell
your message's receiver where to get all files, aaaaaaa - eeeeeee, and
the size of the original file, let's say, 12345 bytes. Receiver:
pad-s 12345 pad-md5-*.dat -o myfile.txt Wrote myfile.txt
Now your receiver has the same file you started with, myfile.txt.
Possible Uses
Free speech enforcement:
Let's say you have a file called decss.c (for example ;), and want to
distribute it, but are afraid of censorship. Break it up into two pad
files, distribute these each on separate unrelated systems, and tell
people where to get each (and how to re-assemble them). Should someone
go to one (or both) of the hosting systems and pressure them to remove
it, each can claim they're only hosting harmless, random data. It is
mathematically impossible to prove that either one is the random one
and the other was derived from the original file.
Another possibility here (and probably better) is the use of 5 or more
pad files for this. This is shown in the second example above. See
http://www.eleves.ens.fr:8080/ho me/madore/misc/freespeech.html for
more information about this.
Privacy:
One-Time-Pad (OTP) encryption dates to long ago, and is in many ways
much more secure than other forms of encryption that can be brute
forced. Keep a private random pad between those you want to share data
with, and simply transmit messages that have been merged with this pad,
via any medium. OTP encryption is as secure as your random source (in
this case, from OpenSSL), and the pad itself. Keep in mind it's called
"One-time pad" for a reason -- If you use the same pad on two different
plaintexts, the messages (either one) can no longer be considered
secure.
AUTHOR
Pad was written by xercist <xercist@mindless.com> This manpage was for‐
matted by Aidian <aidian@spod.org>, from text written by xercist.
EXTRA
You can likely find support and/or information regarding this program
on irc.stratius.com in #pad.
Version 1.0.4 July 2000 Pad(1)
