PKI Compatibility

Having a PKI implementation does not eliminate the need for Registered Email. In an environment where a PKI system is correctly implemented, digital certificates can be used to provide message integrity, confidentiality, authenticity and non-repudiation. The recipient of a message can use the PKI system to prove the integrity and authenticity of a message assuming the chain of CA trust is valid and unbroken. However, the sender cannot use PKI to prove that a message was delivered to an external recipient. The PKI system does nothing for the sender to verify and prove message delivery.

The RPost system can work in conjunction with the PKI system to add value to the messaging process with proof of delivery. Further, RPost Digital Seal technology can extend authentication to the second, third+ recipient as email is forwarded (recipients can verify authorship and original content). With PKI systems, often the act of forwarding an email breaks the capability for a future recipient to verify the email origin and authenticity.

How Registered Email integrates with PKI implementations:

1. Outlook Digital Certificate Integration options.
   The RPost Add-In for Microsoft Outlook has the option to integrate with users' digital certificates. However, this option is only compatible with certain PKI implementations. The Registered Email® software can utilize commercial X.509 certificates that are stored in the Outlook Local Address Book for recipients. The user can configure one certificate from the local user certificate store to be defined as the email user certificate. If this option is used the Outlook, a user can send "Registered" messages that are encrypted and signed using the RPost Add-In.
2. RPost Mail Server Filter and PKI Integration.
   If an RPost Mail Server Filter is installed then mail clients can send "Registered" messages using the subject-line tagging method (see RPost Mail Server Filters above). If this method is used, then messages can be encrypted using any PKI implementation.