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Product Version | Office 2010 Compatible (The default encryption algorithm is AES 128-bit. AES 192-bit and AES 256-bit are supported.) (Recommended Choice) | Office 2007 Compatible (The default encryption algorithm is AES 128-bit. AES 192-bit and AES 256-bit are supported) | Office 2003 Compatible (RC4 Encryption) | Office XP Compatible | Office 2000 Compatible | Office 97 Compatible |
|---|---|---|---|---|---|---|
Office for Mac 2011 (Recommended Version) | Yes | Yes | Yes | Yes | Yes | Yes |
Office 2010 (Recommended Version) | Yes | Yes | Yes | Yes | Yes | Yes |
Office for Mac 2008 | No | Yes (AES 128-bit, read-only) | Yes | Yes | Yes | Yes |
Office 2007 SP2 | Yes | Yes | Yes | Yes | Yes | Yes |
Office 2003 with Office 2007 SP2 Compatibility Pack | Yes | Yes | Yes | Yes | Yes | Yes |
Office 2003 | No | No | Yes | Yes | Yes | Yes |
Office XP | No | No | No | Yes | Yes | Yes |
Office 2000 | No | No | No | No | Yes | Yes |
Office 97 | No | No | No | No | No | Yes |
*Note: Encryption functionality is available on Word, Excel, PowerPoint, and Access. However, not all Office suite products have encryption functionality (e.g. Outlook, Publisher, etc.).
**Note: Documents that are saved as Open XML Format files and encrypted by using Office 2010 can only be read by Office 2010, Office 2007 SP2, and Office 2003 with the Office 2007 SP2 compatibility pack. To ensure compatibility with all previous versions of Office, you can create a registry key (if it does not already exist) under HKCU\Software\Microsoft\Office\14.0\<application>\Security\Crypto\ called CompatMode and disable it by setting it to 0. The values that you can enter for <application> represent the specific Office application that you are configuring this registry key for. For example, you can enter Access, Excel, PowerPoint, or Word. It is important to realize that, when you set CompatMode to 0, Office 2010 uses an Office 2007 compatible encryption format, instead of the enhanced security that is provided by default when you use Office 2010 to encrypt Open XML Format files.
Reference http://technet.microsoft.com/en-us/library/cc179125.aspx#section3
***Note #2: If your organization uses the Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint File Formats to encrypt Open XML Format files, you should review the following information:
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