Adobe ACROBAT 3D Manual page 346

Using eEnvelopes to send secure files
When adding security to a document, you can choose to encrypt only the attachments. The
PDF document in which documents are embedded is called an eEnvelope. Encrypting only
the document attachments is especially useful for sending secure file attachments without
modifying the file attachments themselves. The eEnvelope is not otherwise encrypted or
permission-restricted. When other users open the eEnvelope, they can extract the file
attachments and save them to disk. The saved files are identical to the original file
attachments and are no longer encrypted when saved.
For example, suppose that you want to send several documents, including non-PDF
documents, to your accountant, but you don't want anyone else to view the documents.
You can embed these documents as file attachments in an eEnvelope, encrypt the
eEnvelope so that only your accountant can open the attachments, and then email the
envelope. Anyone can open the envelope, view its cover page, and even view a list of the
contents of that envelope, but only your accountant can view the encrypted attachments
and extract them to the computer.
Attach files to an eEnvelope for secure transit.
Related Subtopics:
Creating eEnvelopes for secure delivery of file attachments