microsoft.com Home  
Microsoft
http://www.microsoft.com/office/ork  
Using Security Features in Outlook

Encryption Strengths for Secure E-mail Messaging

There are two classes of encryption key strengths available from Microsoft: 128-bit Domestic Only and 40-bit International.

The following table summarizes the capabilities of Domestic Only encryption.

Encryption algorithm Key length
RSA 128 bit
3DES 168 bit
CAST 64 bit
DES 56 bit
RSA 40 bit
CAST 40 bit

The following table summarizes the capabilities of International encryption.

Encryption algorithm Key length
RSA 40 bit
CAST 40 bit

Note   For signing, the Digital Signature Key lengths for Domestic and International encryption are RSA 1024-bit and RSA 512-bit, respectively.

Microsoft Office 2000 includes a technology that determines whether the user’s installation is capable of 128-bit Domestic encryption operations. Microsoft provides 128-bit encryption capabilities in Microsoft Internet Explorer 3.02, Internet Explorer 4.x, Internet Explorer Service Packs, Windows NT 4.0, and Windows NT 4.0 Service Packs. These are the programs that the Windows® installer tests for certified 128-bit encryption capabilities during Office 2000 Setup.

If your system already has 128-bit encryption capabilities, Office 2000 installs new 128-bit encryption components during Setup. Systems that do not already have 128-bit encryption capabilities receive 40-bit encryption components.

If 128-bit encryption capabilities are required, and if installation is allowed by US government restrictions, then the Outlook 2000 Domestic Security Pack installs 128-bit encryption components for Internet Explorer 4.x or later and Outlook 2000. The Domestic Security Pack is installed after the Office 2000 installation is completed.

Note   When users exchange e-mail messages internationally, Outlook uses the minimum encryption strength that is supported by the e-mail client application of both the sender and the recipient of the message.

Top

See also

You can upgrade to 128-bit encryption for Outlook 2000 by downloading the Outlook 2000 Domestic Security Patch. For more information, see the Outlook 2000 high encryption page on the Office Update Web site at http://officeupdate.microsoft.com/info/outlook2000highencrypt.htm.



Topic Contents   |   Previous   |   Next   |   Top

Friday, March 5, 1999
© 1999 Microsoft Corporation. All rights reserved. Terms of use.

License