7381ae66_ystems___MIT_Technology_Review__Description
PDFPostman www.encryptomatic.com Yes (operates via programs for PDF and ZIP) [Protection from distribution] None [Description] 
A set of plug-ins for Outlook make it possible to convert a message to a PDF file or ZIP archive with a password before sending. Then the file is sent as an attachment and may be unpacked using any PDF viewer or ZIP archive program. Embedded features of PDF and ZIP are applied for encryption.
Overview of Electronic Mail Protection Systems | MIT Technology Review
Description