how to create a locked excel spreadsheet

However, the opposite could happen where you decrease the protection strength of a file by re-protecting an Excel 2013 file inside of Excel 2010. This scenario would obviously work in your favor as Excel 2013 security is much harder to get past. The strength of security depends on which version of Excel you place the protection NOT the version it is created.įor example, if you created a password-protected worksheet in Excel 2007 and then unlocked & re-locked the same spreadsheet in Excel 2013, your worksheet would now have Excel 2013 level password protection (with the longer Hash and Salt Values). While Excel's password security is still relatively simple (from an experienced computer hacker's point of view) to break, there is now a huge gap in the level of security provided by versions of Excel prior to 2013 versus the versions following 2010. This is probably the most important part of this article as it is vital that you understand how secure your workbooks and worksheets are. Understanding How To Control Your Password Protection Strength The below XML code was inside a workbook where I used the password 'SpreadsheetGuru' to protect a blank worksheet.

A Hash is the output from a Hash Algorithm (complicated mathematical equation) that turns any user-generated password into a jumbled-up string of (appearingly) meaningless characters. Here's a fun fact: Excel does not actually store the password you input! Like most password protection software out there, the Excel Application stores a string of data called a Hash. I won't go into detail on where to find the password information however I will show you an example of how the code is written in both Excel 2007-2010 and in the more secure Excel 2013 version. Likewise, if you understand how these zipped files are written and organized, you can determine settings, data, and even password information made by the user who created the Excel file. Magically your Excel file is transformed into a bunch of files with lots and lots of computer (OpenXML) code! This is important to know as this is where you can dig into how an Excel file is made up. Don't believe me? Go to one of your Excel files on your computer and change its extension from. Many don't know this, but every individual Excel file is really a.

How to create a locked excel spreadsheet