Encrypt Microsoft Office Documents

If you are a Windows user, you often use the Office Suite to write documents, prepare presentations or do some financial calculations. Sensitive documents can be given a degree of protection using Office built-in encryption. Microsoft offers several features to help restrict access to documents through the use of passwords or encryption.

If encryption is enabled, the document is scrambled with an encryption code, making the contents of it unreadable to anyone who does not have the password required to decrypt the document. There are several encryption algorithms available for use with Word, Excel, and PowerPoint files.

Password and encryption options are accessible in the Security tab within the Tools -> Options dialog. You can also access them when saving the file from File -> Save As -> Tools -> Security Options(General Options for Excel documents). In the Security tab, click Advanced and select the type of encryption you want to use, and enter your password.


You also have the option of adding a registry value to set a default encryption type for all Office applications that can use encryption methods. The default encryption algorithm for a standard installation is not the strongest possible. Therefore, if you constantly encrypt your Office documents, it is advisable to set a higher level of encryption.

To set the default encryption type, open the Registry editor and navigate to HKCU\Software\Microsoft\Office\11.0\Common and create a new key called Security. Under the Security key create a new Multi-String value called DefaultEncryption and set its value to “Encryption Provider”, “Encryption Type”, “Key Size”. You can get these values from the Advanced menu in the Security tab.