I was looking at the temporary internet files on my computer.  A
particular item contained the words "private cache" and had several
heavy veritcal bars and other symbols before and after the words. 
When I looked at the description, it said endoded, or encrypted. (I
have already deleted the file and am going on memory.) Can anyone tell me what
this is?

Hi!

You were most likely looking at a file which the author did not intend
your browser to save in its "temporary internet files" folder. Proxy
servers, as well as some dynamic web applications technologies (for
example, Microsoft Active Server Pages or Java Servlets) allow authors
of web pages to add the following "HTTP header" to the page being sent
to their browser:

Cache-Control: private

Essentially this should direct your browser to NOT save a local copy
of the file on your hard disk.

Why might authors do this? Security, for one. Many online banking
sites want to make sure that your account information is not stored
locally on your computer. Another reason would be the author of the
page wanting you always to retrieve a specific page directly off the
server.

Many times, when visiting a web page repeatedly over a single browsing
session, you will be seeing a local copy of that web page that your
browser had previously "cached", or stored locally. Browsers do this
to speed up your browsing experience as well as save valuable network
resources (or "bandwidth") for not only you, but also your ISP, many
ISPs betwen you, and the author's server.

As for the second part of your question mentioning the page was
"encrypted", you were likely viewing a page that had been sent to your
browser via Secure Sockets Layer, or SSL. Any online banking service
or e-commerce site implements SSL for secure communication between
their servers and your browsers. This prevents anyone from
intercepting, or snooping your internet traffic.

For more information on the above, I recommend the following sites:

World Wide Web Consortium (W3C) HTTP1.1 Header Field Definitions:
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9

About.com: Proxy Servers & You
http://compnetworking.about.com/library/weekly/aa061000a.htm

Netscape.com: Secure Sockets Layer
http://home.netscape.com/security/techbriefs/ssl.html

While you won't be able to exactly tell what site served you this file
without still having it, I hope the above will at least explain what
type of file you were looking at.

If you require any clarification, don't hesitate to ask!

I used the following search terms for your query:

Cache-Control: Private 
://www.google.com/search?hl=en&q=Cache-Control%3A+private

Proxy faq
://www.google.com/search?q=proxy+faq&hl=en

Have a great day!

Axe