Until 2004 the encryption used in Microsoft Office was flawed.
The “protect document” option was only useful to prevent accidental editing.
How to open Microsoft office protected documents
Even if you use the latest version of Office there are products that (supposedly) are able to crack the password, again, especially if you use a weak password.
A 5-digit password should be crackeable in seconds using free software from the 1st Google result for “ms word password recovery”
The following are some options you can try to open a protected document.
Option 1 – Google Docs
- Upload your protected document to Google Docs.
- Convert to Google Doc format.
- Read contents. No code required.
Option 2 – Zip trick
The protect spreadsheet in Office 2010 is still only there to prevent accidental editing, to remove simply do the following:
- Open the xlsx as a zip file. (Right click > Open with > Your preferred zip program)
- Find the sheet in the xl\worksheets folder
- Find the xml tab and clear the “password”