interception. Entitled “The Value of Bulk Passive”, it contained the following
summary:
“Bulk [interception] also gives us the ability, and flexibility, to detect target use
of new technologies and find alternative selectors ... If we didn’t have this,
we’d be limited to basic contact chaining, which would restrict us to operating
in the domain of the original selector ... and we’d not be able to tell whether
new technologies were of interest.”
5.48.
The same document identified bulk interception as being “critical” for work that
required retrospective analysis, was urgent or time-bounded, and for detection
work that was based on the use of a technology or on patterns of behaviour or
movement. The author recognised that CNE would in future be far more broadly
deployed than it was at present, but expressed the view that bulk interception
would continue to be pivotal to the success of CNE: it was the use of bulk
interception that provided the basic understanding of the system which could
then be targeted by CNE.
5.49.
A number of recent papers expressed the view that bulk interception remained
valuable despite the “significant threat to the value of bulk passive” that was
posed by the increased use of encryption. The documents overall indicate that
GCHQ’s public warnings about the “going dark” threat accurately reflect its
private thoughts; but also that it perceives bulk interception as retaining a
significant value, particularly in combination with CNE (or EI) and other
techniques.
Conclusion
5.50.
I concluded in AQOT, in relation to bulk interception, that:
“its utility, particularly in fighting terrorism in the years since the London
bombings of 2005, has been made clear to me through the presentation of
case studies and contemporaneous documents on which I have had the
ability to interrogate analysts and other GCHQ staff.”211
5.51.
Outlines of six of the dozen case studies on which I based that conclusion were
annexed to AQOT,212 including three in which exercise of the power by GCHQ
led to arrests or the prevention of an attack in other countries. Though it was
possible to cite those case studies only in outline, they illustrate in particular the
ability of bulk data to identify previously unknown perpetrators of suspicious
activity. As I stated in AQOT 7.27: “They leave me in not the slightest doubt that
bulk interception, as it is currently practised, has a valuable role to play in
protecting national security.”
211
212
AQOT (June 2015), 14.45.
AQOT, Annex 9 (para 1 of that Annex was included in error).
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