The ALG that is part of a CDS, when transferring information between different security domains, must implement organization-defined security policy filters requiring fully enumerated formats that restrict data structure and content.

Data structure and content restrictions reduce the range of potential malicious and/or unsanctioned content in cross-domain transactions. Security policy filters that restrict data structures include, for example, restricting file sizes and field lengths. Data content policy filters include: 1) Encoding formats for character sets (e.g., Universal Character Set Transformation Formats) 2) American Standard Code for Information Interchange (ASCII) 3) Restricting character data fields to only contain alpha-numeric characters 4) Prohibiting special characters 5) Validating schema structures Organization-defined security policy filters which require format restrictions depend on the environment, data, and security boundaries. Organizations implementing CDS must follow the DoD-required process of testing, baselining, and risk assessment to ensure the rigor and accuracy necessary to rely upon a CDS for cross domain security.