DESCRIPTION
Maybe you have a web application and you need to store some session data
at the client side (in a cookie or hidden form fields) but you don't
want the user to be able to mess with the data. Maybe you want to save
secret information to a text file. Maybe you have better ideas of what
to do with encrypted stuff!
This little module will convert all your data into nice base64 text that
you can save in a text file, send in an email, store in a cookie or web
page, or bounce around the Net. The data you encrypt can be as simple or
as complicated as you like.
CHANGES
Version 0.05 had a few missing subroutine bodies, so quite a few things
didn't work! I'm now practising what I preach, and have written some tests!
INTERNALS
"Crypt::Simple" is really just a wrapper round a few other useful Perl
modules: you may want to read the documentation for these modules too.
We use "FreezeThaw" to squish all your data into a concise textual
representation. We use "Compress::Zlib" to compress this string, and
then use "Crypt::Blowfish" in a home-brew CBC mode to perform the
encryption. Somewhere in this process we also add a MD5 digest (using
"Digest::MD5"). Then we throw the whole thing through "MIME::Base64" to
produce a nice bit of text for you to play with.
Decryption, obviously, is the reverse of this process.
WARNING
Governments throughout the world do not like encryption because it makes
it difficult for them to look at all your stuff. Each country has a
different policy designed to stop you using encryption: some governments
are honest enough to make it illegal; some think it is a dangerous
weapon; some insist that you are free to encrypt, but only evil people
would want to; some make confusing and contradictory laws because they
try to do all of the above.
Although this modules itself does not include any encryption code, it
does use another module that contains encryption code, and this
documentation mentions encryption. Downloading, using, or reading this
modules could be illegal where you live.
AUTHOR
Marty Pauley <marty@kasei.com>
COPYRIGHT
Copyright (C) 2001 Kasei Limited
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License; either version 2 of the License,
or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.