Network Security Hacks [Electronic resources] نسخه متنی

Hack 28 Encrypt Your Temp Folder

Keep prying eyes out of your temporary
files.

Many
Windows applications will
create intermediary files while they do their work. They typically
store these files in a temporary folder within the current
user's settings directory. Most often these files
are created world-readable and aren't always cleaned
up when the program exits. How would you like it if your word
processor left a copy of the last document you were working on for
anyone to come across and read? Not a pretty thought, is it?

One way to guard against this situation is to encrypt your temporary
files folder. To do this, open an Explorer window and go to the
C:\Documents and Settings\<username>\Local
Settings folder. In this folder you should see another
folder called Temp. This is the folder that
holds the temporary files. Right-click the folder and bring up its
Properties dialog. Make sure the General tab is selected, and click
the button labeled Advanced. This will bring up an Advanced
Attributes dialog, as seen in Figure 2-6. Here you
can choose to encrypt the folder.

Check the "Encrypt contents to secure
data" box and click the OK button. When you have
done that, click the Apply button in the Properties dialog. Another
dialog (as seen in Figure 2-7) will open asking you
whether you would like the encryption to apply recursively.

To apply the encryption recursively, choose the
"Apply changes to this folder, subfolders and
files" option. This will
automatically create a public-key pair if you have never encrypted
any files before. Otherwise, Windows will use the public key that it
generated for you previously. When decrypting, Windows ensures that
the private keys are stored in nonpaged kernel memory, so that the
decryption key will never be left in the paging file. Unfortunately,
the encryption algorithm used, DESX, is barely an improvement on DES
and is nowhere near as strong as 3DES. However, it serves the purpose
of transparently encrypting temporary files very well. If you want to
encrypt other files, it is suggested you use a third-party utility
such as GnuPG (http://www.gnupg.org), which has Windows
binaries available on its web site.