Formulas can be gotten by removing the worksheet passwords, see

http://www.mcgimpsey.com/excel/removepwords.html

VBA source code can be accessed using commercial crackers or hex
editors. In fact, with hex editors, you can view the code in the file -
it's tokenized so that it's not easily human readable, but it's often
easy to get the gist of the code.

The most secure way to protect code is to develop compiled COM add-ins.
Unfortunately, they won't work with XL97 or any Mac version.

In article ,
Geo Siggy wrote:

Addition to my question: I dont mean cracking the given password, thats
another topic. I mean getting to the formulas or vba source code
through a backdoor are a transfer methode.
Does anybody have a clue ...