As can be seen in Technical Requirements For End-to-End Encryption under "Disadvantages", genuine end-to-end encryption with external communication partners is only possible if their public keys are already present on the sending device. Conversely, the external communication partners must be in possessions of the corresponding public key of the internal sender.

 

The SEPPmail Secure E-Mail Gateway is able to automatically adapt itself to the situation of the internal and external recipient and to automatically select the most suitable technology for securing the email to be sent.

Here, the following technologies are available:

•S/MIME
 

•OpenPGP
 

•Domain encryption
 

•GINA (technology for the spontaneous communication with anyone)
 

(please also refer to Encryption Hierarchy)

 
Generally, an email server does not transmit an internal email to an external recipient. However, since an encryption gateway is positioned between the email server and the Internet in the email flow, if applicable, internal emails must be transmitted externally up to the encryption gateway in order to use the latter for internal email encryption.