Protocol breaks and content checking are technologies used under the hood. These technologies relate to the principal information security objectives, and ultimately how confidential information is protected using data diodes.
When protecting an isolated network against outsider attacks, there are a number of objectives and technologies that are commonly used. Objectives typically boil down to C.I.A.: confidentiality, integrity and availability.
The best possible technology for confidentiality is the unidirectional network connection by means of a data diode. However, there is a lot of technology relating to data diodes that impacts integrity and availability. In particular, protocol breaks and content checking have a subtle relation to these objectives.
This briefing paper explains how data diodes are used to protect confidential information.