OL2002: Recipients Cannot Read Messages When 168-Bit (3DES) Encryption Is Enabled (307472)

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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.

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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.