Using RTF (Rich Text Format) with PGP Encryption can result in missing annotations
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Using RTF (Rich Text Format) with PGP Encryption can result in missing annotations

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Article ID: 163281

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Updated On:

Products

Encryption Management Server Gateway Email Encryption

Issue/Introduction

Microsoft Outlook can use three types of message format:

  1. HTML
  2. Plain text
  3. RTF (Rich Text Format) - this format is specific to Outlook

Using RTF with PGP encryption can result in missing annotations:

  • If the encrypted message contains inline graphics, the recipient sees no annotations around the body of the message. The message therefore appears not to have been encrypted.
  • If the encrypted message does not contain inline graphics, annotations are displayed as normal.
  • If the encrypted message has an attachment, the attachment is decrypted as expected.

This occurs whether PGP Encryption Desktop or PGP Encryption Gateway is used to encrypt or decrypt messages.

 

Environment

PGP Encryption Server and PGP Encryption Desktop 10.5 and above.

Cause

If the body of the outbound RTF message only contains formatted text, whether or not the message has an attachment, recent releases of Outlook will automatically convert the RTF message body to HTML format. The raw message will include a text/html section with this comment:

<!-- Converted from text/rtf format -->

However, if the message contains inline graphics, no conversion to HTML takes place and instead all rich text formatting and inline graphics are contained in a binary winmail.dat attachment. This winmail.dat file is encrypted by the sender's PGP Encryption Desktop or Server and decrypted by the recipient's PGP Encryption Desktop or Server. Outlook then decodes the winmail.dat file. Because winmail.dat is a binary file, no annotations can be added by PGP Encryption Desktop or Server.

Resolution

There are two main ways of working around this issue:

  1. Ask the sender to use HTML format (plain text format is also an option).
  2. Ask the sender's organization to configure Microsoft Exchange to automatically convert Rich Text Format messages to HTML format before they are sent over the Internet to external recipients.

Additional Information

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