Microsoft KB Archive/184226

= XADM: How Advanced Security Works on a Mailbox =

Article ID: 184226

Article Last Modified on 10/28/2006

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APPLIES TO


 * Microsoft Exchange Server 4.0 Standard Edition
 * Microsoft Exchange Server 5.0 Standard Edition
 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q184226



SUMMARY
Microsoft Exchange Server supports three encryption algorithms: CAST-64, DES, and CAST-40. The level of encryption is determined by the Exchange and/or Outlook client, not the server. The U.S./Canada version of all Microsoft Exchange Client products supports all three algorithms, but defaults to CAST-64. All other international (localized) versions of Exchange Client support only the CAST-40 (40 bit) algorithm.



MORE INFORMATION
When you are using a CAST-64 or DES client, Exchange sends the message based on the encryption information in the mailbox or individual mailboxes that it is sending to. The CAST-64 and DES clients can read all encrypted mail.

When you are using a CAST-40 client, the directory for that mailbox is updated so that other users will send only 40-bit encryption. While you are logged on to the CAST-40 client, you can not read messages encrypted with CAST-64 or DES encryption.

Keywords: kbinfo KB184226

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