To expand on the previous response and add a bit of clarification,
Office 97 - Office XP use R4 encryption. Office 2003 also utilizes R4
encryption, so files are compatibility with previous Office versions,
but provides for stronger encryption types.
Additionally Office 2003 can be protected using Information Rights
Management (IRM) which AFAIK can not be cracked.
I tested a popular password cracking software which claims they can
crack a password of any length provided it is a dictionary word, and
up to 9 characters using brute force. I protected a document with a
strong password 9 characters in length and let the utility run on a PC
I wasn't using for 123 hours, 49 minutes, and 5 seconds. It never
cracked the password - I finally gave up!
Also note that the utility uses so many resources it's next to
impossible to run additional software while it is running.
Something else to keep in mind, if you purchase such a utility you are
giving your credit card number to a known crack. <g>
--
Please post all follow-up questions to the newsgroup. Requests for
assistance by email can not be acknowledged.
~~~~~~~~~~~~~~~
Beth Melton
Microsoft Office MVP
Word FAQ:
http://mvps.org/word
TechTrax eZine:
http://mousetrax.com/techtrax/
MVP FAQ site:
http://mvps.org/