此
technet article确认默认值为AES 128位密钥,SHA1,CBC.
Although there are Office 2010
settings to change how encryption is
performed,when you encrypt Open XML
Format files (.docx,.xslx,.pptx,and
so on) the default values — AES
(Advanced Encryption Standard),
128-bit key length,and CBC
(cipher block chaining) — provide
strong encryption and should be fine
for most organizations.
但是,需要注意的是,加密是出口控制的,并且所有版本的Windows都可能没有安装所有加密提供程序.本文还提到您可以通过检查注册表项来查看安装了哪些加密服务提供程序：
HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Cryptography/Defaults/Provider
