XOmail has been designed and implemented as a Multi-Level Secure system operating under control of a certified Security Kernel (“Trusted Computing Base”). All messages have a Security Label assigned to them. Individual interfaces are assigned security label ranges and status (e.g. MLS, System-High with or without advisory Labels).

External cryptographic devices can be utilized to ensure that classified messages are transmitted on authorized channels only. Logs, journals, and audit information are automatically generated and stored. Server initiated virus control can be activated.
 

Messaging Security Services

Security services are implemented according to STANAG 4406 using the S/MIME-based PCT-protocol. Digital Signatures are used to ensure that e.g.

• the origin can be verified by the recipient

• the message is unaltered

• the originator can have a proof of reception

Certificates are used to carry the signature and optional privileges. A Smart Card is typically used to hold a user’s Private Key. Certificates are handled by a replaceable Public Key Infrastructure (PKI).
 

Secure servers

Utilizing its Multi-Level Security characteristics, XOmail is able to serve as a secure gateway between networks with different security characteristics. A local server configuration may have one or more segments at different levels, and both classified and non-classified external connections. The secure server will ensure that security is under no circumstances compromised.   Security Gateways Manual inspection and re-labelling of messages (“Security Review & Release”) from System-High domains are built-in to allow release of messages below the System-High level in a trusted manner. A trusted by-pass option can be used between domains operating with the same policy.