Friday, 2 January 2015

The tangled net of GCHQ’s fishing warrant

[Updated 8 February 2015 and 10 June 2015]

The Section 8(4) RIPA warrant is the most powerful interception tool available to UK intelligence agencies. While a targeted Section 8(1) warrant has to name a person or a set of premises, a section 8(4) warrant can authorise bulk interception of millions of simultaneous communications on an internet backbone.

Periodically renewed Section 8(4) warrants are thought to authorise GCHQ’s TEMPORA programme of tapping into transatlantic fibre optic cables, which reportedly processes 40 billion items of data per day.

Following the Snowden revelations a group of NGOs including Liberty, Privacy International  and Amnesty International challenged Section 8(4) in the Investigatory Powers Tribunal. The IPT found in December that, in the light of disclosures of interception practice made by the government in the proceedings, future use of Section 8(4) warrants would be ‘in accordance with the law’ under Article 8 of the European Convention on Human Rights. The legality of previous Section 8(4) interception has still to be determined. [Now held to have been lawful: IPT judgment 6 Feb 2015, para 12.]

The justification for the Section 8(4) warrant is that investigating terrorism and crime abroad is harder than domestically. It is said that a Section 8(4) warrant is primarily aimed at external communications (sent, received or both outside the British Islands) and not primarily at people located here; and that the purpose of accessing external communications is primarily to obtain information about people abroad. (IPT judgment, [145] and [147]).

But is the purpose of Section 8(4) to gain access to external communications? Or is it to gain access to the communications of people outside the British Islands? Is it a mixture of the two? Bearing in mind that people within the British Islands may send and receive external communications, the objectives are significantly different.

In fact Section 8(4) goes some way towards both objectives, but gives full effect to neither.  The result is a warrant with an avowed purpose to intercept external communications, but which in reality sweeps up both internal and external communications and then treats them identically. Or, if its purpose is to access communications of people outside the British Islands, it nevertheless allows some access to the communications of people within the British Islands.

These points are especially significant when it is appreciated that under Section 8(4) not only capture of communications but also their searchability does not depend on pre-existing grounds for suspicion. The bulk capture stage is suspicionless. Agencies trawling the intercepted material are then not confined to looking for activities of known suspects. The agencies can use keyword and other subject-matter searches to fish for new targets in the general pool of captured internal and external communications.  It is apt to describe Section 8(4) as a fishing warrant. 

This dual use of RIPA was confirmed by senior Home Office official Charles Farr in the IPT proceedings:

“Other information that is obtained via interception is used to identify other previously unknown communications of existing targets, and to identify new targets for investigation. Indeed, a significant proportion of initial intelligence leads derive from interception operations.” (emphasis added) (Farr witness statement, paragraph 31)

This article discusses how the Section 8(4) warrant implements the two avowed purposes and concludes with some observations on points for consideration in the forthcoming likely reform of RIPA.

How far is it the purpose of Section 8(4) to gain access to external communications?

A Section 8(4) warrant, like a targeted Section 8(1) warrant, has to be for a statutory purpose: national security, preventing or detecting serious crime or safeguarding the UK’s economic wellbeing (if relevant to national security).  These purposes govern all three stages of the Section 8(4) warrant structure: Capture, Select, Examine. The scheme is illustrated in this diagram:

The first stage, Capture, is the only point at which the internal/external communication distinction is relevant. In terms of the broader Section 8(4) legislative scheme the distinction plays no more than a fleeting introductory role. This has become more obvious following the judgment of the IPT.

Section 8(4) (in conjunction with Sections 8(5) and 5(6)) authorises “the interception of external communications in the course of their transmission by means of a telecommunication system”. However it also authorises “all such conduct (including the interception of communications not identified by the warrant) as it is necessary to undertake in order to do what is expressly authorised or required by the warrant”.

In other words, internal as well as external communications can be captured under a Section 8(4) warrant if they are unavoidably swept up in the interception process. 

On 4 July 2000 the government Minister Lord Bassam, in a letter to Lord Phillips during passage of the Bill, pointed out that:

“Clause 8(5) could, for example, make lawful the interception of internal communications where these mixed with external communications on a trunk used mainly for external purposes.”

In the House of Lords debate on the Bill on 12 July 2000 he said:

“It is still the intention that Clause 8(4) warrants should be aimed at external communications. Clause 8(5) limits such a warrant to authorising the interception of external communications together with whatever other conduct is necessary to achieve that external interception. Whenever such a warrant is signed, the Secretary of State must be convinced that the conduct it will authorise as a whole is proportionate—my favourite word—to the objects to be achieved. His decision to sign will be overseen by the Interception of Communications Commissioner.”

In the IPT proceedings Charles Farr said:

“Section 5(6)(a) makes clear that the conduct authorised by a section 8(4) warrant may in principle include the interception of communications which are not external communications insofar as that is necessary in order to intercept the external communications to which the warrant relates. But the primary purpose and object of any conduct authorised or required by a section 8(4) warrant must consist in the interception of external communications.” (witness statement, paragraph 155)

With this emphasis on external communications we might expect the distinction between internal and external communications to suffuse the whole of the Section 8(4) regime including the subsequent selection and examination stages. 

In fact, as can be seen from the IPT’s judgment, the distinction has no relevance at those stages:

“It is also common ground that the interception under a s.8(4) warrant (what the Respondents call “Stage one”) occurs before any question of selection for examination (what the Respondents call “Stage two”) arises under s.16. As Mr Ryder put it, the relevance of the internal/external distinction has no relation to the s.16 examination, when a communication may be accessed and read. The identification of communication links for interception is, as he described it, a ‘generic’ exercise, not an exercise which is done specifically case by case and communication by communication.” [95] (emphasis added)

The criteria that constrain selection and examination are different from internal/external communication.

The primacy that Section 8(4) accords to external communications at the capture stage is thus of limited significance.  External and internal communications are inseparable as they pass through a fibre optic cable. If the Secretary of State’s purpose is to capture external communications, and he has a basis for believing that the warrant will fulfil that purpose and is necessary and proportionate, Section 8(4) in practice authorises the capture of all communications passing through the cable whether internal or external. The captured communications, both internal and external, then form a common pool and are treated alike.

The limited significance of the external/internal distinction in the overall scheme of Section 8(4) can also be seen in the IPT’s discussion of the position if the Secretary of State had adopted an incorrect legal interpretation of ‘external communication’.

“…the distinction only arises at “Stage one”, when there is no examination:

i) All communications, whether they be external or internal, intercepted by s.8(4) warrant come to be considered for examination by reference to s.16 of RIPA, to which we turn below. It is that section which does what Mr Ryder called in argument the “heavy lifting”.” (emphasis in original) [101]

The IPT also referred to what it termed ‘inchoate’ external communications. This reflects the fact that in many cases the intercepting agency cannot know whether it is capturing an internal or an external communication. This is because the distinction depends on the location of the sender or recipient when the communication is sent or received respectively. For communications such as e-mails, the location of the recipient cannot be determined by looking at the communication or its related communications data.  The location of the mailbox may be ascertainable, but that cannot reveal the location of a person who picks up the message after the interception has taken place.

Lord Bassam recognised this for mobile roaming during the Parliamentary debate on the Bill:

“Even after interception, it may not be practicably possible to guarantee to filter out all internal messages. Messages may well be split into separate parts which are sent by different routes. Only some of these will contain the originator and the intended final recipient. Without this information it will not be possible to distinguish internal messages from external. In some cases it may not be possible even if this information is available. For example, a message between two foreign registered mobile phones, if both happened to be roaming in the UK, would be an internal communication, but there would be nothing in the message to indicate that.” (emphasis added) (Hansard, 12 July 2000)

The IPT judgment observed:

“It is inevitable that, when a telephone call is made from a mobile phone or IPhone, or an email is sent to an email address, it will not necessarily be known whether it will be received in the United Kingdom or in the course of travel or at a foreign destination. It is accepted that once and if received abroad by the intended recipient it will be an external communication, even if the sender did not know, when he or she made the call or sent the email, that that was to be the case.” [(94(iii)]

Selection and Examination – people outside the British Islands?

The Selection and Examination stages follow Capture. Examination is the point at which human analysts can read, look at or listen to captured material.  Although they are limited to examining material described in the Secretary of State’s certificate on the warrant, that description could be as wide as all communications between the UK and a named country, or passing through a particular cable.  

More significantly, analysts can (with some exceptions) only examine material that has been selected in ways that do not breach the Section 16(2) prohibitions. These are the provisions that do the ‘heavy lifting’ referred to by the IPT. Generally they reflect the second avowed purpose of Section 8(4) – to gain access to the communications of people outside the British Isles, but not those of people within the British Isles.

Lord Bassam, in the House of Lords debate on 12 July 2000, said:

“selection may not use factors which are referable to an individual known to be for the time being in the British Islands”

However RIPA is not that straightforward. Under Section 16(2) a selection factor is prohibited if it:

“(a) is referable to an individual who is known to be for the time being in the British Islands; and
(b) has as its purpose, or one of its purposes, the identification of material contained in communications sent by him, or intended for him.”

Lord Bassam’s summary reflects (a), but not the significant additional limitation in (b). This narrows the scope of the Section 16(2) prohibition, enabling at least one kind of search to be made using the name of someone known to be within the British Isles.  

Some examples illustrate the apparent effect of the Section 16(2) prohibitions. These apply whether the captured communications were internal or external.

-         An analyst could not (without a modification to the warrant) search for Joe Smith’s communications by (say) his e-mail address if he knows that Joe Smith is within the British Islands.  

-         If Joe Smith’s communication turns up in response to:
o   a subject matter search (e.g. ‘Syria’), not referable to any individual
o   a search using someone else’s name (not known to be within the British Islands) or the name of a corporation
o   a search for his own name within the body of someone else’s communication
o   a search for his own name aimed at finding his own communications, if the agency does not know that he is for the time being within the British Islands
then according to the letter of Section 16(2) it could apparently be examined.  (However if the examination itself involves a process of further selection, an analyst could be prohibited (without a warrant modification) from focusing on communications of someone known to be within the British Islands of which s/he becomes aware during examination.)

-         If Joe Smith has left the British Islands since sending the communication, then the analyst could apparently search using his name, since Joe Smith is no longer ‘for the time being’ within the British Islands

As to the last point, the IPT judgment could be read differently (para 143):

“Communications intercepted under a s.8(4) warrant cannot be read if sent by or to a person located in the UK, by reference to the s.16(2) procedure discussed at some length above.”

However that would not take account of ‘for the time being’, which on the face of it refers to the time of search, not the time of the communication.

This extract from the Foreign Secretary’s evidence to the Intelligence and Security Committee on 23 October 2014 also seems to conflate time of communication and time of search:

“The Foreign Secretary clarified after the meeting that, if a communication is intercepted under an s.8(4) warrant, and if one end is outside of the UK, it may be selected for examination without a 16(3) modification if the subject of interest is the non-UK end of the communication; however, if the subject of interest is the party in the UK, or if both ends are UK, there needs to be a 16(3) modification or 8(1) warrant authorised by the Secretary of State before it can be selected. He undertook to write to the Committee with further detail.”

Section 16 provides some limited gateways permitting examination even if the material was selected using factors prohibited by Section 16(2). 

The most potentially significant gateway is an additional certificate under Section 16(3). This allows otherwise prohibited examination if the Secretary of State certifies that selection by factors referable to the individual in question is necessary for national security, prevention or detection of serious crime, or national security-related UK economic wellbeing; and the material relates only to communications sent during a maximum period of three months (six months for national security). The extent to which Section 16(3) has been used is not public. 

There is also a procedure known as an ‘overlapping’ Section 8(1) targeted warrant. The procedure was first described in the Interception Commissioner’s Report for 1986 under the pre-RIPA interception regime. It appears that its purpose is to buttress the examination of communications to or from persons within the British Isles legitimately available for examination through the Section 8(4) procedure. However the procedure’s exact use and legal significance is unclear. The status of overlapping warrants and their relationship to Section 16(3) were issues during the passage of the Bill.

Reform of RIPA

Several reviews of RIPA are currently in progress. They include the Investigatory Powers Review by the Independent Reviewer of Terrorism Legislation under the Data Retention and Investigatory Powers Act 2014 (DRIPA), due to report by May 2015; the RUSI Independent Surveillance Review and an inquiry by the Intelligence and Security Committee of Parliament.

Reform of RIPA will be a priority after the 2015 General Election, with legislators mindful of the sunset date of 31 December 2016 for the RIPA amendments made by DRIPA. The pros and cons of Section 8(4) warrants will be hotly contested. Among the possibilities that we can anticipate being advocated may be:
-         Abolish all suspicionless bulk capture of communications.
-         Limit selection and examination under a Section 8(4) warrant to communications of pre-existing suspects.
-         Maintain the status quo.
-         Enact more extensive powers.

There will of course be debate around broader overarching issues such as whether it is any longer appropriate to treat communications data as deserving less privacy protection than content.

RIPA is notoriously difficult to understand.  The convoluted selection and examination provisions of Section 16 are among the most difficult to untangle. Whatever the eventual policy outcomes of the forthcoming debates, any new legislation should be clear, accessible and reflect the purposes for which it is enacted. 

The discussion above highlights some specific issues that are likely to have to be considered should Section 8(4) survive in any recognisable form.

Before commenting on these, one fundamental issue that will be relevant to any interception regime is hidden legal interpretations.

Hidden Legal Interpretations

Legal interpretations are critical to the operation of RIPA. An obvious example is the interpretation of ‘external communications’.  Others mentioned in this article include overlap of selection and examination, what constitutes an agency’s knowledge of someone’s whereabouts and whether it is bound to make enquiries, the relevance and extent of the various statutory purposes said to be embodied in the legislation, the significance of ‘for the time being’ in section 16(2) and the legal effect (if any) of overlapping warrants.  There have been other examples, such as extra-territoriality.

The agencies conduct their activities on the basis of legal interpretations of the legislation which generally remain hidden from view.  It took the extraordinary event of the Snowden disclosures for the government to reveal, in the resulting IPT proceedings, its particular (and widely criticised) interpretation of external communications.

It would be a significant step forward if the Interception Commissioner (or any future equivalent oversight body) were to be charged with publishing legal interpretations on the basis of which the agencies operate under interception legislation.

Turning to specific issues around Section 8(4):

Incidental awareness

Section 16(2) is structured as if selection and examination are separate phases. Yet if that were so, analysts would be able to examine and use material of which they became incidentally aware as a result of a permitted search, but which they could not legitimately have targeted directly. 

If while reading a communication selected by means of a permissible factor an analyst becomes interested in its sender or recipient, and that person is known to be within the British Isles, does that amount to selection? Does Section 16 then prohibit further examination without a modification to the warrant? This ought to be the case, and may be supported by para 105 of the IPT judgment, but is less than clear on the face of the statute.

This kind of issue may be covered in internal intelligence agency guidance documents.  It ought to be specifically and clearly addressed in legislation. It also may bear on the use of overlapping Section 8(1) warrants.

Internal/external communications

Warrants to intercept external communications go back to Section 4 of the Official Secrets Act 1920, which used the same definition of external communications as does Section 8(4). However the distinction now has limited significance in the overall scheme of Section 8(4) warrants. It is also curious that Parliament should have knowingly hung Section 8(4) on the slender thread of something largely unascertainable.

That is not to say that the distinction has no constraining effect on the initial interception stage. For instance, could a Secretary of State sign a Section 8(4) warrant to tap a domestic cable carrying 99% internal communications if his primary purpose and object was genuinely to capture some of the 1% external communications?

The Secretary of State would have to consider whether the warrant was necessary and proportionate, including in particular whether the information thought necessary to obtain under the warrant could reasonably be obtained by other means (Section 5(4)). Such considerations, and the requirement to certify a description of intercepted material considered necessary to be examined, ought to drive a Secretary of State towards directing Section 8(4) warrants at cables that are most likely to contain the highest proportion of external communications.  That approach is borne out by Charles Farr’s witness statement in the IPT proceedings (para 154):

“Thus, when conducting interception under a section 8(4) warrant, knowledge of the way in which communications are routed over the internet is combined with regular surveys of internet traffic to identify those bearers that are most likely to contain external communications that will meet the descriptions of material certified by the Secretary of State under section 8(4)(b)(i) of RIPA. While this approach may lead to the interception of some communications that are not external, section 8(4) operations are conducted in a way that keeps this to the minimum necessary to achieve the objective of intercepting wanted external communications.”

While broad considerations of necessity and proportionality give some comfort, they are not the most concrete of protections.  If Section 8(4) were to survive in anything like its current form, consideration might be given to, for instance, explicitly restricting it to international cables.

If it remained an avowed purpose of a Section 8(4) replacement to focus on interception of external communications, then consideration could be given to extending that beyond the capture stage. The agency could be required (to the extent feasible) to sift out and discard internal communications after capture. It could be required to cease examining a communication that it realised was internal. If a selection/examination distinction based on a person's location within or outside the British Islands were to be retained, then the scope for examining communications of people within the British Islands would bear reconsideration .  

Knowledge of location of a person

The prohibited Section 16(2) selection factors refer to an individual ‘known’ to be within the British Isles.  The agency is therefore on the face of it free to search for the communications of someone whose whereabouts are unknown, or if it suspects but does not know that the individual is within the British Isles (IPT judgment, [104] - [105]).

‘Known’ presumably means known to the agency.  Does that mean known to the particular analyst responsible for setting the selector, known to a group of analysts, or include anything in the records and archives of the agency?

Does it include information within the intercept material itself? One would assume not, since the agency could never safely set a name selector to search the pool of intercept material if it was deemed to know everything within it.

However there is a relevant difference between content and related communications data captured under a Section 8(4) warrant.  The section 16(2) restrictions do not apply to the related communications data.

The government argued before the IPT that this was justified by the use of related communications data in order to determine whether someone was for the time being within the British Isles. This was necessary in order for the safeguard in Section 16(2)(a) to work properly:

“In other words, an important reason why the Intelligence Services need access to related communications data under the s.8(4) Regime is precisely so as to ensure that the s. 16 safeguard works properly and, insofar as possible, factors are not used at the selection that are - albeit not to the knowledge of the Intelligence Services - “referable to an individual who is ... for the time being in the British Islands”.” [112]

The government submitted that this was plainly the express, and sensible, purpose of Parliament.

The government argument seems implicitly to posit some duty on the agency to enquire into the location of a selection target, albeit that is not spelt out in Section 16.

The IPT accepted that the different treatment of communications data

“is justified and proportionate by virtue of the use of that communications data for the purpose of identifying the individuals whose intercepted material is to be protected by reference to s.16(2)(a).”[114]

The IPT rejected the NGOs’ argument that use of communications data for this purpose could be addressed by an exception in the legislation, saying that it was an “impossibly complicated or convoluted course”. That issue could be revisited in any reform of RIPA.

[Updated 2 Jan 2015 15.30 with additional reference to certificates; and 23.30 to substitute British Islands for British Isles (thanks to @RichGreenhill for pointing that out; and 3 Jan 2015 15:11 to add reference to RIP Bill debate on S16(3)/overlapping warrants.); and 8 February 2015 to add reference to further IPT judgment; and 10 June 2015 to add references to Sections 8(5) and 5(6).]


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