Equisys technical notes

Technical guidance, explanations and fixes for our products

PRB: Cannot render digitally signed or encrypted messages from Outlook



ID: ZTN1410

This Zetafax technical note applies to:

  • Zetafax with the Exchange 5.5 or 2000/2003 connector
  • Doctiff or conventional email gateway rendering (STOLE)


When sending faxes from Outlook with encryption or digital signatures enabled, the message is rendered without error, but contains Multipurpose Internet Mail Extensions (MIME) coding similar to the screenshot below.

Digital signatures and encryption keys can be obtained from third-party companies like VeriSign, and are designed to authenticate or encrypt email messages for added security.


When using a digital signature, Outlook encapsulates the message in a special MIME format. As none of the Zetafax rendering methods support this type of attachment, it is rendered as plain text, including MIME codes.


Turn off encryption and digital signatures for each fax message using the icon on the standard Outlook toolbar.

Alternatively, to turn off encryption and digital signatures in Outlook for all messages, go to Tools, Options, Security, and disable both "Encrypt contents and attachments for outgoing messages" and "Add digital signatures to outgoing messages".


This has been identified by Equisys as a problem with the software versions given above.

Last updated: 7th October 2004 (EB/SV)

Keywords: Exchange Outlook digital sign encrypt multi-part message render

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