Saturday, 15 November 2014

Of straws and haystacks

Much post-Snowden attention has been directed to GCHQ’s TEMPORA programme, authorised (so it is thought) by a rolling series of external interception warrants under section 8(4) of RIPA. (See foot of this post for an explanation of Section 8(4) warrants and the restrictions, particularly for communications of persons within the British Isles, on their use.)

TEMPORA captures communications in bulk from transatlantic fibre optic cables, then filters them by computer leaving a residue of sifted material that GCHQ and NSA analysts can examine. It is said to process 40 billion items a day.

The often repeated justification for bulk collection and sifting is that we have no method of identifying and separating individual communications at the point of collection, so we must gather the straws and sift the resulting haystack. The usual metaphor is looking for needles, implying objective distinctions. It may be better to think of looking for straws.

What kind of straws can be looked for? The haystack can, within the restrictions laid down by RIPA, be sifted to detect the straws of pre-existing persons of interest. However Section 8(4) warrants go beyond that.  The captured material can also be searched and analysed to form new suspicions.   Home Office official Charles Farr said of RIPA in his witness statement in the current Investigatory Powers Tribunal 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)
We do not know what proportion of initial leads are false positives, casting suspicion on blameless people. We do not know how many true positives the system misses. Moreover suspicion is a highly subjective matter.

History suggests that general collection and subject matter analysis was an established approach to external communications long before today’s separation problems arose.

The ancestor of RIPA Section 8(4) was Section 4 of the Official Secrets Act 1920, legislated in the immediate aftermath of the First World War following the lapsing of wartime powers.  It empowered the Secretary of State to issue a warrant requiring a telegraph operator to hand over telegrams entering or leaving the country:
“Where it appears to a Secretary of State that such a course is expedient in the public interest, he may, by warrant under his hand, require any person who owns or controls any telegraphic cable or wire, or any apparatus for wireless telegraphy, used for the sending or receipt of telegrams to or from any place out of the United Kingdom, to produce to him, or to any person named in the warrant, the originals and transcripts, either of all telegrams, or of telegrams of any specified class or description, or of telegrams sent from or addressed to any specified person or place, sent or received to or from any place out of the United Kingdom by means of any such cable, wire, or apparatus, and all other papers relating to any such telegram as aforesaid.”
The Attorney General Sir Gordon Hewart introduced the provision in Parliament as a measure for detecting foreign spies:
“The postal and cable censorship which we had during the War, and which was of the greatest possible value and importance, was removed shortly after the Armistice. That being so, it is necessary that there should be power at least to compel the production of the originals and the transcripts of certain telegrams. It is not a power to stop telegrams. It is merely a power to compel the production of the originals and transcripts sent to, or received from, any place out of the United Kingdom; and the main purpose of that provision is to enable the authorities to detect and deal with attempts at spying by foreign agents.”
Earl Winterton invoked a familiar mix of foreign threats and ‘nothing to hide, nothing to fear’:   
“Everyone knows we do not live in ordinary times. Everyone knows there are plots and conspiracies against this Realm which are being carried out in foreign countries and some parts of the British Empire, and that, however one may dislike the idea of imposing additional restrictions on the subject, it is necessary for the Government to have that power. I suggest there is nothing to interfere with a person going about his legitimate business. The right hon. Gentleman, for example, made great play with Clause 4 of the Bill. … Surely he does not suggest that in the critical time in which we are living to-day a Secretary of State should not have power, if it seem desirable in the opinion of the Government that he should exercise that power, to find out what is being cabled to and from this country. Of course, it is a most necessary power, which every government ought to have.”
John Thorpe MP put the State firmly ahead of the individual:
“… In my view the State is in great danger, and no power which would tend to protect it should be withheld from the Government. We heard something from the same right hon. Gentleman of the liberty of the subject. In my view, the subject has no liberty when it is in conflict with the good-being of the State. When the liberty of the individual conflicts in any way with the well-being of the State, then it becomes license.  
… The law-abiding citizen, the man who says that his country is his first consideration, need have nothing to fear whatever from the Clauses of this Bill. … The only man who has anything to fear is the man who puts self before country, the man who says, "I want liberty, and the State can look after itself." He is a danger, and I congratulate the Government on the efficient manner in which they propose to deal with him.”
The legislation duly passed. For nearly 50 years Section 4 did its work in obscurity. The 1957 Birkett Inquiry into interception of communications did not mention it. (The Birkett Committee’s terms of reference were limited to the executive power to intercept, which was different and separate from the statutory power to issue warrants under Section 4.)

Things changed in February 1967.  Section 4 came to public notice when journalist Chapman Pincher revealed in the Daily Express that cablegrams sent out of Britain were being collected from the Post Office and private cable companies for scrutiny. This incident is most famous for sparking the ensuing D-Notice row. But the substance of Pincher’s ‘Cable Vetting Sensation’ story is of interest here. He revealed that:
“There is no hold-up or censorship of the cables. But on the morning after they have been sent or received they are collected and sifted by a Post Office department concerned with security. Then any cables believed to be of special interest are passed to the Security Services. 
They are studied there, copied if necessary, and returned to the Post Office and cable offices after being held for 48 hours. 
Most of the original cables and telegrams go out through the Post Office, which owns the former Cable and Wireless Company. Cables passed through private companies—mainly branches of foreign concerns operating in Britain—are collected in vans or cars each morning and taken to the Post Office security department. 
The probe is conducted under a special warrant, signed by a Secretary of State under Section 4 of the Official Secrets Act and regularly renewed to keep it valid.”
A week later Alan Watkins in the Spectator wrote:
“Indeed, sources confirm that a Ministry of Works van regularly takes cables—it is not clear whether they form a random sample, or come from a particular sender or class of senders—along to the Ministry of Defence for examination. The authority for such action is section 4(1) of the Official Secrets Act, 1920.”
The Radcliffe Report on the D-Notice affair confirmed the substantial accuracy of Pincher’s story:
“It does involve a regular collection of copies of messages transmitted by the Post Office and other cable offices with a view to the total collected being sorted and certain defined categories of them being set aside for inspection by the intelligence agents of Her Majesty’s Government. … 
The practice is authorised in law by section 4 of the Official Secrets Act, 1920 … . According to the information given to us, this power has been regularly exercised against transmitting companies since the coming into operation of the Act. … 
In fact only a small percentage of the total telegrams handled is put aside [by the sorters for inspection]. … The Daily Express article was … not inaccurate in any sense that could expose it to hostile criticism on that score.”
The Government White Paper published simultaneously with the Radcliffe Report said it would be contrary to the public interest to say in what detailed respects the article was misleading. It also said:
“It was precisely because national security was threatened that, from the outset, the Government regarded the publication of certain information in the Daily Express of 21 February as a matter of the utmost gravity. … It is the duty of the government, in the light of all the advice they have received and the information they possess, to record that the effect on national security of that publication has been to cause damage, potentially grave, the consequences of which cannot even now be fully assessed.”
The White Paper complained that the article created:
“the sensational impression that the Government were responsible for introducing new and sinister procedures.  There were, and are, no such new and sinister procedures. The activities involve no element of prying into the private affairs of the citizen. Such activities are, in fact, carefully controlled and confined and the article was misleading when it inferred the Government might use them improperly.”
Although the government denied (supported by the Report) that any new practice had recently been introduced, the possibility that routine vetting was a long established practice was left open.

Several themes from this episode resonate today:
  • Bulk collection, sifting and examination
  • Periodically renewed warrants
  • Revelations about the extent of use of powers, answered by denials that the powers are abused
  • Assertions, to be taken on trust, that publicity has caused damage to national security
  • Intrusion into privacy rebutted on the basis of close control over the intrusion
  • Bulk collection defended on the basis that only a small percentage of the items collected is inspected

Like the 1957 Birkett Report, the Home Office and Diplock Interception Reports of 1980 and 1981 made no mention of the Section 4 powers.  The reports were limited to statistical information about non-statutory warrants.  

The reports recognised the invasion of privacy involved in interception warrants. Lord Diplock said:
“The exercise by the State of any power to read or listen to communications taking place between private citizens involves an invasion of their privacy which has always been looked upon by the public with suspicion and distaste.”
The 1920 powers lasted until 1985, when they were replaced by the Interception of Communications Act (IOCA). The preceding White Paper had promised that the legislation would include provisions “along the lines currently covered by the Official Secrets Act 1920.” Whilst IOCA folded interception of external communications into the new statutory system for issuing warrants, the warrantry power for external communications continued to be broader than for internal communications.

So what is now the Section 8(4) warrant trod its own quiet path from 1920 to 1985, exposed to public scrutiny only once as a result of the Chapman Pincher cable vetting story – to which the Government of the day reacted almost identically as did the government of today to Edward Snowden’s TEMPORA disclosures.

A vanload of cables is on a smaller scale than 40 billion items of data per day, but the principle and method is the same: general capture, selection, examination. Long before any technical argument that targeted interception is impossible, the 1920 legislation enabled the government to engage in suspicionless bulk capture followed by subject-matter analysis of external communications.

In Chapman Pincher’s day collected telegrams and cables were evidently sorted manually. Human beings looked at them all and decided which were worthy of further examination. Now the initial capture, sift and discard is computerised.  The government argues that capture involves only a technical interference with privacy compared with a human being examining intercept material:
"The Respondents accept that the interception of a communication under a s. 8(4) warrant may be regarded as giving rise to a technical interference with the Art. 8 rights of the parties to the communication even if that communication is not and/or cannot be read, looked at or listened to by any person." (Open Response, IPT proceedings)
Going back further than 1920, in 1765 Lord Camden, the judge in Entick v Carrington, held that general search warrants had no legal basis. It is perhaps idle to speculate how he might have reacted had Lord Halifax (the then Secretary of State) said:
“Fear not, Mr Entick.  True we have ransacked your home, broken the locks on your desks and cupboards and seized your papers and correspondence.  But, since we have not yet examined any of them, that is a merely technical breach of privacy.  We have strict safeguards in place to ensure that we will only look for material about that renegade Wilkes who is outside the British Isles, skulking in Paris.”

Footnote: How does a Section 8(4) warrant work?

The Foreign Secretary can issue a RIPA warrant for purposes of national security; for preventing or detecting serious crime; for safeguarding the economic well-being of the United Kingdom (if related to national security); or, in relation to serious crime, mutual legal assistance treaties with other countries. He must believe the warranted interception and disclosure to be proportionate to what it seeks to achieve; and must take into account whether the information he thinks it necessary to obtain could reasonably be obtained by other means.

A Section 8(4) warrant, unlike an ordinary RIPA Section 8(1) warrant, does not have to be targeted at the communications of a particular person or premises. It can authorise general bulk collection at the level of the cable. But while a targeted Section 8(1) warrant can be used to intercept internal communications (those sent and received within the British Isles), the overall purpose of a Section 8(4) warrant must be the collection of external communications (sent or received outside the British Isles). So external communications are those where both ends of the communication, or only one end, are outside the British Isles.

Internal and external communications tend to be inseparably mingled within a single fibre-optic cable. So RIPA allows a S.8(4) warrant to authorise the capture not only of external communications, but any internal communications unavoidably swept up with them.

After capture of the communications come selection and examination. RIPA constrains these in different ways.

Captured communications (whether internal or external) can be examined if they are within a description certified by the Secretary of State in the warrant. That description could be very broad. However they can be selected for examination only in a way permitted by RIPA’s selection rules. These govern the automated filtering down of the captured communications to a database of material and also the queries made by analysts against the database.

The rules restrict the use of selection factors targeting the communications of people known for the time being to be in the British Isles. But despite this there are several gateways via which a communication sent or received by someone in the British Isles and captured under a S8(4) warrant could end up being examined by a GCHQ analyst.

Foreign Secretary Philip Hammond touched on two of the gateways in a clarification of his recent evidence to the Intelligence and Security Committee of Parliament. He posited a communication (say an e-mail) between someone in the British Isles and someone abroad. In general terms it could not be selected where the subject of interest is the person in the British Isles. That would require a further step such as the Secretary of State’s modification of the S.8(4) warrant under the exception in RIPA S.16(3). However the e-mail could be selected for examination if the person outside the British Isles is the subject of interest.


1 comment:

  1. As ever, the government simply states the time we are living in is exceptional. That's all they ever need do to pass what they want.

    ReplyDelete