Microsoft Office password protection is the security feature of MS-Office productivity suite (Word, Excel, and PowerPoint) with the user-provided password. In Office setup 2007 this used the strong encryption whereas the earlier version used the weaker systems and aren’t considered secure.
Office 2007-2013 used 128-bit key and Office 2016 using 256-bit key AES password protection which also remains secure. Office 97-2003 password protection used 40-bit key RC4 contains multiple vulnerabilities, making it insecure.
Microsoft Office password protection application mainly concentrates on the main groups of passwords that can be easily set to the documents depending on encrypt password-protected document or not.