Attachment encryption is similar to full message encryption with the following exceptions:
- The message body is not encrypted. Only the attachments are encrypted. The password recovery information is included in the message footer. If you wish to reply securely then click the link in the footer to launch the compose page.
- The attachments aren't wrapped in a single file. Each attachment is encrypted as a separate file.
- The attachment format depends on the type of file being encrypted. Your encrypted attachments may be a mixture of PDF files, Microsoft Office and ZIP files.
If the attachment is in a ZIP file format, you can use an approved file archiver to open the zipped files, for example: 7-Zip.