The goal of the Research Task Group in Cross Domain Security Solutions (IST-068/RTG-031) of the NATO Science and Technology Organization (STO)  was to improve the sharing of information in military environments and to facilitate the evolution of a flexible infrastructure by utilizing the eXtensible Markup Language (XML) to create suitable security solutions.

In 2010, the group published for a proposal for an XML Labelling and Metadata Binding specification.

This work has gone on to be developed into two new Standards Agreements (STANAGS), which in turn, are cover documents for the associated Allied Data Publications (ADatPs)):

• STANAG 4774 – Confidentiality Metadata Label Syntax – an XML schema that can be used to represent a confidentiality (security) label.
• STANAG 4778 – Metadata Binding Mechanism - an XML Schema that can be used to bind arbitrary metadata (including metadata that uses the confidentiality metadata label syntax, to pieces of information.

Both of these STANAGs are currently in the process of being ratified by the NATO Nations.

STANAG 4774 defines the structure of a confidentiality label, which includes elements such as the policy identifier, classifications and security categories. The non-normative Annexes B and D of STANAG 4774 provide descriptions of two security labelling policies, “NATO” and “PUBLIC”, in the form of Security Policy Information Files (SPIFs), which provide the value domains for the elements of the confidentiality label.

The SPIFs in the STANAG obviously can only contain a snapshot of the NATO security labelling policy, as new categories are added and removed to support missions and exercises. However, an up-to-date SPIF is maintained in the NATO Metadata Registry and Repository (NMRR) (login required), along with the STANAG 4774 and 4778 XML schemas, and other associated artefacts.