When transferring information between different security domains, the router must use organization-defined data type identifiers to validate data essential for information flow decisions.

Information flow decisions based on invalid data may allow unintended and unauthorized data flows, and therefore, risk the confidentiality of information. They may also result in the unauthorized release (spill) of information.

Data type identifiers include, for example, file names, file types, file signatures/tokens, and multiple internal file signatures/tokens. Information systems may allow transfer of data only if compliant with data type format specifications.

This requirement applies to routers that transfer information between different security domains (e.g., cross-domain solutions).

This requirement also applies to Zero Trust initiatives.