(Updated: November 26, 2014)
Most of the documents leaked by Edward Snowden are from the American signals intelligence agency NSA, but there are also quite a number from their British counterpart GCHQ. Documents from both countries are classified as TOP SECRET and often have additional markings to further restrict their dissemination.
Where on American documents we see markings like COMINT (Communications Intelligence) and NOFORN (No Foreign Nationals), the British have the mysterious term STRAP followed by a number.
Information about American classification and dissemination markings can rather easily be found on the internet (see also The US classification system on this weblog), but there are hardly any details about the British classification system.
But luckily, there's one source available which describes STRAP and other British classification practices in detail: the extensive Defence Manual of Security from 2001. Chapter 17 (page 1131-1135) of Volume 1 gives an overview of the STRAP Security Guidelines.
In the manual, STRAP is described as a set of nationally agreed principles and procedures to enhance the "need-to-know" protection of sensitive intelligence (and related operational information) produced by the British intelligence agencies, including military sources.
It adds additional procedures to the standard security measures employed for intelligence matters. STRAP is therefore comparable with the American system of protecting the most sensitive information by control systems with separate compartments, which are generally designated by codewords.
Although on some websites it's suggested that STRAP might stand for "STRategic Action Plan", the Defence Manual clearly states that STRAP is a codeword, not an acronym. The STRAP codeword itself is not classified.
Some intelligence information, handled within the STRAP System, require more stringent protection than others. To assure this, there are three levels of STRAP protection. These levels are designated, in ascending order of sensitivity and, hence, access control: STRAP 1, STRAP 2 and STRAP 3.
Examples of STRAP documents
An example of a document from the least sensitive category, marked STRAP 1, is a slide from a powerpoint presentation about the BULLRUN program aimed at breaking encryption methods used on the internet:
Information that is somewhat more sensitive is marked STRAP 2, like this presentation slide about operation SOCIALIST, which infiltrated the network of the Belgian telecommunications provider Belgacom:
From the category of most sensitive documents, marked STRAP 3, there are no actual examples available. STRAP 3 for example protects the precise locations where these interceptions takes place. The real names of the telecommunication companies that cooperate with GCHQ are classified one level below this, at STRAP 2.
As several of these real names have been published, Snowden must somehow got access even to STRAP 3 documents. Probably because they are so sensitive, Greenwald and the papers may have decided not to publish them, but only use some of the information they contain.
STRAP protection measures
The STRAP system is designed to protect information against threats that are specific for sensitive intelligence. A principal threat is when a target becomes aware of an intelligence attack against him, so he can initiate countermeasures. Therefore, the STRAP system aims to minimise the risk of leakage of sensitive intelligence operations and products into the public domain - whether by accidental exposure or deliberate intent. This is done through the following measures:
- Restricting access to sensitive intelligence material on a strict "need-to-know" basis;
- Agreeing the appropriate facilities for its protection in transit ("STRAP Channels") use, storage and disposal;
- Providing explicit briefings and guidance for individuals who handle this type of material.
Information that requires protection under the STRAP system has to be clearly defined and labelled with the appropriate STRAP level marking. It has to be carried by authorized couriers during transit, and signed receipts have to be obtained at all stages of handover.
Within the British Ministry of Defence, the implementation of the approved STRAP security measures is overseen by individually appointed STRAP Security Officers (STRAPSOs). The overall responsibility for the review and formulation of STRAP policy and guidelines is with the STRAP Management Board.