Microsoft KB Archive/307472

= OL2002: Recipients Cannot Read Messages When 168-Bit (3DES) Encryption Is Enabled =

Article ID: 307472

Article Last Modified on 7/27/2006

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APPLIES TO


 * Microsoft Outlook 2002 Standard Edition

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This article was previously published under Q307472



IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SUMMARY
By default, Microsoft Outlook 2002 defaults to 40-bit (RC2-40) encryption when another encryption algorithm is not available. If you configure Outlook to default to 168-bit (3DES) encryption instead, and then you send a message to an e-mail client that does not support that encryption algorithm, the recipient is unable to read the message.



MORE INFORMATION
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

If the UseAlternateDefaultEncryptionAlg value exists under the following registry key, Outlook is configured to use a different default encryption algorithm:

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security

If one or more recipients cannot read messages that you send when Outlook is configured in this manner, remove the UseAlternateDefaultEncryptionAlg value so that Outlook defaults to 40-bit (RC2-40) encryption. To do so:  Click Start, and then click Run. In the Open box, type regedit, and then click OK. Locate and click the UseAlternateDefaultEncryptionAlg value under the following registry key:

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security

 On the Edit menu, click Delete, and then click Yes. Quit Registry Editor.

Keywords: kbhotfixserver kbqfe kbbug kbfix kbofficexpsp1fix KB307472

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