The concerns addressed herein are mostly in relation to the provisions of Part III of the Bill, which deals with lawful access to "protected information" which has been encrypted. Each of the little stories which follows describes some (possibly unintended, but nevertheless undesirable) feature of this part of the Bill. A few scenarios, starting with scenario 22, address problems identified in Part I of the Bill.

The latest version of this present text may always be downloaded from <http://www.cs.man.ac.uk/~chl/scenarios.html>.

See my Roadmap of Schedule 1 for the convoluted arrangements that are proposed for issuing Notices under Section 46 of the Bill.

Please see my document "Where we are at" and my "Comments on Report Stage Amendments" for the present state of progress (or lack of it).

Please see the companion document Amendments proposed by Dr C. H. Lindsey for some proposed solutions to the problems identified in Part III of the Bill, and Part I Amendments proposed by Dr C. H. Lindsey for further amendments specifically related to Part I.

Code of Practice

This matter assumes particular importance because the Minister, when explaining why some particular matter is not covered in the Bill, has regularly been saying that it would be covered by the Code of Practice (and claiming much benefit in this approach insofar as the code would take full account of consultations "with industry"). However, the absence of any draft code makes it exceedingly hard to discern the effect of certain parts of the Bill, and it should moreover be born in mind how relatively easy it will be for the Secretary of State to change the code as time goes by, even though an affirmative resolution of both Houses will be needed for any such change.

Dramatis personae

Introductory

Scenario 1 - public-key cryptography explained

Alice and Bob each have two "key pairs", one for "signature", and one for "encryption". Each key pair is composed of two keys, a "Public Key" (which everyone in the world can know) and a "Private Key", which must be a secret known only to its owner (Alice or Bob, as the case may be).

When Bob sends a message to Alice

1. Bob signs it with his Private Signature Key (which only he knows).
2. Bob then encrypts the message with Alice's Public Encryption Key (which everybody knows).
3. Alice decrypts the message with her Private Encryption Key (which only she knows).
4. Alice checks the message with Bob's Public Signature Key (which everybody knows) and thus she can be sure that the message came from Bob, and that it has not been tampered with.

And so Plod, even when it is Bob's criminal activities that he is investigating, has to serve his Section 46 Notice on the innocent Alice in order to find out what is in the message. Moreover, if Plod obtains Alice's Private Key as a result of his notice, he is thereby enabled to decrypt all communications received by Alice, from whomsoever they may come, and indefinitely far into the future. Which is why the Bill gives Alice the option to decrypt the message upon Plod's request, rather than handing over her cherished Private Key. Except that the Bill gives that option grudgingly, with the possibility of insisting on the key in "special" circumstances.

Note that if Plod were able to demand Bob's Private Signature Key, then he would be in a position to impersonate Bob. Which is why announced Government Policy and the relevant E.C. Directives, and the wording of the Bill all make it absolutely clear that Plod is not able to demand Signature Keys. Except that the wording of the Bill  does not actually prevent such demands (of which, again, more anon).

Scenario 2 - symmetric keys and session keys

However, it turns out that clandestine meetings are not really necessary. Bob can easily send Alice a symmetric key using Alice's Public Encryption Key. In fact, for technical reasons, this is absolutely standard practice. The symmetric key is then known as a "session key" and it is typically used for just one communication, and then discarded. Liken the session key to a key that will open just one door, whereas the Public Encryption Key is the Master Key that will open any door in the Hotel. The government claims that disclosure of a session key is always sufficient to satisfy the requirements of the Bill. We shall see.

Symmetric keys (usually in the form of a cryptographic hash of some "passphrase") are also likely to be used for protecting data stored on a hard disc. The Bill also makes provision for disclosure of keys in this case.

It also turns out that it is possible for Alice and Bob to agree on a symmetric key without ever meeting at all, and in full view of Eve, so that neither Eve, nor Plod, nor any provision of this Bill will ever be able to decrypt their communications. Indeed, it is always wise to remember that a sufficiently well-informed criminal can always circumvent any provision of Part III of this Bill.

The Form of Notices

Scenario 3 - was it delivered?

The same problem arises in S22:(1)(a) and S22:(2)(a) in connection with authorizations and notices  regarding access to communications data. With a little bit of luck, there will be some standard procedures set out in the Code of Practice to cover this. See also amendment C46(4)(a).

Scenario 4 - was it genuine?

Was the notice in the proper form? The Bill provides no proper form (it is in such format as the issuer "thinks fit"). But wait! With a little bit of luck, the Code of Practice will specify a standard format.

Who issued it? Well the office, rank or position of the issuer must appear on it (no mention of the name, but I suppose that may be taken for granted), so Alice will be able to check. But she won't be able to check whether the issuer was authorised to issue it, because it will not identify the person (Schedule 1) who gave permission for it to be issued (recall that the issuing of a Section 46 notice is a two-stage process).

Notices sent by electronic means need to be digitally signed, which means that Plod must previously  have provided Alice, in writing, with his Public Signature Key. This would only be useful if Plod expected to serve notices on Alice frequently. The Home Office have stated that matters such as these will be covered in the Code of Practice. Verbal notices should have been outlawed entirely (see amendment C46(4)(a)).

Scenario 5 - when does the notice expire?

Concern has also been raised that this lack of a duration of the notice may violate the ECHR.

Scenario 6 - who does the key have to be given to?

The key should only be deliverable to the class of persons capable of having permission to issue notices, as in Schedule 1:2.  There is suitable wording for this in S22:(3), which covers similar notices regarding communications data. The Minister promised in Committee to look into this further (Hansard Standing Committee F, 4th April, 12 noon) but nothing further has been heard of it. See amendment C46(5).

Scenario 7 - how soon?

It would be far simpler to insert the word "reasonable" at the proper place in S46:(4)(c) (see amendment C46(4)(f)). The government rejected an amendment to that effect at the Committee stage, citing S49:(3)(a) as being sufficient.

Scenario 8 - which key?

Phew! Alice is perfectly correct, as it happens. But Plod still has one straw left to clutch at:
 

Plod

Ah! But you said that your "session key" was encrypted with your Private Key. So that makes the session key protected information. And in that case I am entitled to ask you for the key that decrypts it (i.e. your Private Key). Observe that this notice is a "special circumstances" notice (S47:(4)(a)), which means that I can have the actual key, not just the plaintext.

Alice

Yes, you would indeed be entitled to ask for my Private Key as you say, but for one thing. I have just offered to give you the session key, so you can hardly say you believe that the Private Key is "necessary" under S46:(2)(b)(i), or that it fulfils S46(2)(d). Moreover, you can be certain that the session key I am giving you is the correct one because you will see that you are able to decrypt the body of the protected information with it.

Alice had to follow a tortuous route to establish her point. It could even be argued that the Bill is in contravention of the ECHR at this point, because the right it gives to the noticee could hardly be described as "foreseeable". Indeed, many lawyers who have studied the Bill have failed to notice what the Minister has now established as the correct interpretation.

And it is still not entirely certain that Alice's response to Plod's final ploy would stand up in Court, and I have therefore prepared an amendment C46(2)c to cover it.

It is vital that the Bill should give Alice the right to deliver a session key, where one is available and will satisfy Plod's need to decrypt the protected information, and it is vital that the availability of this right should be widely known, as the next scenario shows. See amendments C46(2)a, C47(2)a and C47( ).
 

The Plaintext Alternative

It is hard to envisage what those special circumstances might be, and the Government has consistently failed to give examples of how it is intended to be used, in spite of being repeatedly so asked. The most we have heard is that the power might be used where the noticee was not to be trusted (and, indeed, production of a session key could reasonably be required in that case). Also, it might be used where there were time constraints (but it takes no longer to provide plaintext than it does to provide a session key, and we are told that session keys will always suffice). And it might be used in cases involving "security", whatever that might mean (Hansard Standing Committee F, 4th April, 4.30 pm).

But, with a little bit of luck, the Code of Practice will set out in full what those "special circumstances" might be.

Scenario 9 - is our Private Key safe?

Sigh! If only Justin had known what Alice knew in the previous scenario. But the significance of session keys as a complete solution to all the problems above seems to have been completely overlooked, not least by the government. Everybody involved in this business (government included) has been talking and behaving as if loss of Private Keys were a real possibility. Real-life lawyers have already been giving the same advice as Justin. And why should this be so? Because the government has failed to point out the true situation, not least by drafting the Bill in such a way as to suggest the exact opposite of what it actually says.

I believe the Prime Minister has said he wants Britain to be the best country in which to carry on electronic business. The Bill, if interpreted as above, would make it one of the worst.

Signature-only keys

Scenario 10 - protection of Private Keys

Evidently, the encrypted key is "protected information" (by S52:(1),(4)). Hence, if it comes into the possession of Plod (by seizure of Alice's computer, for example) Plod may, by notice (S46:(1)(a)), demand Alice's passphrase, notwithstanding he would then hold Alice's signature-only key. Observe that Plod is not in breach of S46:(6)(a). He is not asking for Alice's signature-only key (which he is prohibited from doing). He is asking for her passphrase, which itself is undoubtedly an encryption key.

The Home Office take the view that a Court would regard S46:(6)(a) as prohibiting such indirect access to the signature-only key, but I regard this as being optimistic given the clear chain of reasoning exhibited above. Therefore the possibility should be explicitly prohibited (amendment C46(6)b).

Scenario 11 - authority to access Private Encryption Keys

The box will decrypt cheques upon receipt of an authorizing token digitally signed by one of Chase's transaction processing computers, which itself will only issue such tokens under the circumstances programmed into it, which will include the presence of some further token digitally signed by Bob (who is an official in the company), doubtless in conjunction with a further token digitally signed by several members of the Board of Directors authorizing Bob to exercise that authority.

Thus Bob can use his Private Signature Key (which he uses to sign all sorts of other documents within the company) to create tokens which grant access to the decryption engine inside the iron box. Thus, the present definition of "key" in S52:(1) would appear to cover

1. The Private Key in the iron box
2. The various tokens recognized by the iron box
3. Bob's Private Signature Key

For the removal of all doubt, the definition of electronic signature (S52:(1)) should be strengthened to cover such situations. See amendments C52(1)a) and C52(1)(b).

Scenario 12 - signature keys previously used for encryption

She last used it for decrypting a message 5 years ago. Nevertheless, that is enough to give Plod the right to force her to disclose it (S46:(6)(b)). But why should Plod do such a thing? Suppose Grundy, with malicious intent, sends Alice a message encrypted with the corresponding Public Key (or worse, if it really was a signature-only key, manipulates it so as to be used for encryption - not a difficult feat, technically speaking, with most systems). Of course, he ensures that Plod becomes aware of the fact, together with other suitably incriminating "evidence", and Plod decides to issue a Section 46 Notice. Alice is required to comply (and the fact that she never even decrypted Grundy's message is irrelevant).

S46:(6)(b) should merely require that the signature key had not been used for encryption within some timescale relevant to the matters that are under investigation (amendment C46(6)a).

Scenario 13 - information in obscure formats

Indeed Plod is using an inappropriate sledgehammer to crack this nut, but the present definition of "key" in S52:(1) is on his side. It should be reworded to require that a key, as used for encryption purposes, should be accompanied by an intent to conceal (amendment C52(1)c).

The Offence of failure to comply

Scenario 14 - lost or disused keys

Now Grundy sends her a message using her Public Key from 5 years ago (and provides Plod with incriminating "evidence" as before). Plod serves a Section 46 Notice, and when she fails to comply (she cannot, even though she is otherwise perfectly willing) she is prosecuted under S49, on the grounds that she "has or has had possession" of that key.

The prosecution has to show

• That Grundy's message had come into Plod's possession (under some part of S46:(1)).
• That Plod believed, on reasonable grounds (S46:(2)(a)), that Alice possessed the key to decrypt it (the fact that Grundy had sent it to Alice would appear to be reasonable enough grounds for that).
• That serving a notice was necessary and proportionate (S46:(2)(b,c,d) (we assume Grundy's "evidence" was good enough for that).
• That Plod had served the notice.
• That Alice had not complied (S49:(1)(a)).
• That Alice had had the key (S49:(1)(b)), which indeed she had.

In her defence, Alice is invited to show (S49:(2)(a)) that the key was not in her possession at the relevant time. But how can anyone ever prove that he does not possess something, especially something as intangible as a key? It is impossible, so Alice gets sent to prison for 2 years.

This situation is grossly unjust. The onus of proof has been reversed, contrary to the European Convention on Human Rights (and notwithstanding the Secretary of State's statement in that regard on the front of the Bill). Indeed FIPR have obtained Counsel's Opinion to the effect that this provision is in breach of the ECHR, whereas the government have blandly stated that the advice they have received is to the contrary, whilst nevertheless refusing, on several occasions, to disclose that advice or to cite cases or precedents in support of their view.

Note that the words "has or has had possession" (S49:(1)(b)) were added to the Bill in order to overcome objections that it contravened the ECHR. In fact, those words have made the situation worse.

This issue has been widely debated, usually with more heat than light. People speak in terms of "well everybody forgets their password from time to time" (one ex-minister even admitted that he relied on his wife to remember his). The fact is that it is the deliberate destruction of keys, as described above, that is the more likely cause of these difficulties. For a business that keeps careful records of what keys it has had and when they were destroyed there may be little problem, but that is of no comfort to a private individual such as Alice.

The Liberal Democrats introduced an amendment whose effect would be to require an "intent to impede access to protected information", and to ensure that there was no offence if, at the time of giving the notice, the accused did not have the key, and did not have any means of recovering it. The Conservatives proposed a different version of the same thing (see below). The government, however, flatly refused any concession at all in this matter.

The very least that is required is some time limit on that "had possession" phrase (amendment C49(1)).

Scenario 15 - deliberate refusal to comply

Now Bob knows that the evidence of the pictures, once decrypted, would be sufficient to earn him 10 years in jail (and let us assume that there is insufficient evidence to convict him otherwise). He also knows that the maximum penalty for failure to provide the key (or, equivalently, the plaintext) is a mere 2 years. Therefore he refuses to comply, hence at least avoiding the larger penalty.

The Conservatives have made great play with this scenario, and proposed an amendment to the Bill which went beyond that put forward by the Liberal Democrats by increasing the penalty for non compliance to 10 years, and allowing evidence of previous convictions to be adduced in support of a prosecution. The government has resisted this (whilst promising to review the sentence in the light of actual experience). Moreover, the idea of allowing previous convictions to be disclosed is repugnant to many, including myself, though apparently there are a few precedents in other legislation.

Tipping Off

Scenario 16 - excessive secrecy

• She may not tell Bob (naturally, that is the whole purpose of the exercise).
• She may not tell her other correspondents (whose messages Plod is now able to decrypt, whether or not that would be lawful).
• She may not tell her Boss (even though his whole business is now at the mercy of Plod).
• She may not tell her Boss even if he asks her directly, and if she is sacked for refusing to answer, then that is tough.
• She may not tell her colleague, whose technical assistance she requires in order to comply, and whom the Bill may elsewhere require her to consult (S52:(2)). But if she asks nicely, Plod may give her a dispensation to consult him (S50:(8)).
• She may not tell a court of law, when giving evidence, even though not to tell it might amount to perjury. Nor may she explain to the court why she is unable to answer the question.
• She may not tell her psychiatrist, even though she is having nightmares on account of the stress she has been put under.
• It has been doubted whether she may even publicly revoke her key (for that might send a covert message to Bob). However, the Home Office have now agreed that this would not be an offence (see Scenario 17).

• She may tell her lawyer, but only when asking him to explain this part of the Act to her (S50:(5)), and then only if it does not further any criminal purpose (S50:(7)).
• Her lawyer (but not, apparently, Alice, unless she is a lawyer) may tell, but only in connection with legal proceedings (S50:(6)), and then only if it does not further any criminal purpose (S50:(7)).
• That the disclosure was made by some automatic operation of her computer (S50:(4)(a), but only if she was unable to act quickly enough to stop it (S50:(4)(b)).

Many of the problems here, however, arise from the requirement that the secret must be kept from everybody, whereas it would have sufficed for the Bill to require the notice to say that the secret was to be kept from some named person, or some named class of persons (with a proviso that anyone else informed of the matter was also to be informed of that requirement of the notice). It is a simple matter of "opt-in" as opposed to "opt-out". See amendment C50(1,3,4).

Moreover, the notice ought to specify some time beyond which (subject to renewal of the notice) the secret need not be kept (such time being normally related to the duration of any warrant which contained permission for the notice to be issued).

It should also be noted that a similar problem arises in S18 in regard to interception warrants.

Scenario 17 - indirect disclosure

Alice has disclosed the company's Private Key, but has been instructed to keep the fact secret - even from her Boss. She speaks to her boss.
 

Alice	I think we should revoke our Public Key.
Boss	Why ever would we want to do that?
Alice	I couldn't possibly say.
Boss	Ah! I see! Have you been served with one of those Section 46 notices then?
Alice	I couldn't possibly say.

Has Alice committed an offence? The secret is clearly out, but Alice has not actually said anything wrong.

The Home Office have now agreed that Alice is not guilty here, but their view is still not consistent with the wording in the Bill.. See amendment C50(4).

Scenario 18 - a weepie

• Alice cannot even tell her mother.

Circumstances allowing the issue of Notices

Scenario 19 - economic well-being of the U.K.

So Dodge approaches H.M.Government for assistance. Arrangements are made to intercept communications between Frites and Bob, perhaps by the interception of satellite transmissions. This may require an interception warrant (S5:(1)), but ensuring that Dodge gets the contract surely counts as "safeguarding the economic well-being of the United Kingdom" (S5:(3)(c)) and the information sought clearly "relates to acts or intentions of persons outside the British Islands" (S5:(5)). A notice to disclose the decryption key is served on Bob; surely this too is "in the interests of the economic well-being of the United Kingdom" (S46:(3)(c)).

Can the notice also forbid Bob from tipping off Frites? Yes indeed, provided only that the police or the intelligence services were involved in the interception (S50:(2)(a) and that the "investigating techniques" needed to be kept secret (S50:(2)) (that is why they took the trouble to intercept satellite transmissions, because simply keeping the information secret from Frites is not itself grounds for requiring secrecy under S50).

But Hey! This is not Cricket!

But this ground of the "economic well-being of the U.K." arises in several places in the Bill (S5:(3)(c), S21:(2)(c), S27:(3)(c), S28:(3)(c), S30:(3)(c), S46:(3)(c)), sometimes with a restriction to matters outside the British Islands, sometimes not. What is the purpose of these provisions, if not for the kind of scenario described? It would seem so, from the rather half-hearted comments made by the opposition during the various debates. But if Parliament wishes to give the authorities those powers, then at least the restriction regarding matters outside the British Islands ought to be applied consistently, and certainly in connection with Section 46 Notices (amendment C46(5a)).

Scenario 20 - fishing

Now Hazard is not investigating any crime, nor has he reason to suppose (at this stage) that the data on Bob's computer might reveal any crime (this started out as a routine visit). In plain terms, he is "fishing". Therefore, he cannot claim (S46:(2)(b)(i)) that his key is "necessary" for "preventing or detecting crime" (S46:(3)(b) or for any other purpose in S46:(3)). Therefore he has to rely on S46:(2)(b)(ii), namely that obtaining the key is "likely to be of value" in the performance of his statutory duty.

S46:(2)(b)(ii) is a "fisher's" charter. There is no requirement so weak anywhere else in the bill (cf S21:(2) and S5:(3)). The requirements in S46:(3) provide quite adequate grounds for when Section 46 notices may be issued and are, by and large, the same as those recognized as necessary in the case of interception warrants. Attempts were made to remove this provision at the Committee stage, but were not pursued further. See amendment C46(2)b.

However, the counsel's opinion already alluded to identifies this particular provision as being a further violation of the ECHR, on grounds of its general vagueness when set against the interference with an individual's private life which it seeks to permit.

Scenario 21 - source of protected information

However, if the encrypted data was brought to him (perfectly legally) by a member of the public (a "whistleblower"), he may not obtain such permission, because he is not a police officer (S46:(1)(e)).

This anomaly should be removed.
 

Interception

Scenario 22 - Public, Private and Other systems

• Telecommunication system
• Telecommunications service
• Public telecommunications service
• Public telecommunication system (must be offered to a substantial section of the UK public)
• Private telecommunication system (must be attached, at a point in the UK, to a public telecommunication system)
• Closed telecommunication system (not officially defined, but I shall use it for telecommunication systems which are neither public nor private)

Nothing is said about Closed telecommunication systems, so presumably they are fair game for any eavesdropper (including, but not restricted to, Plod) who can arrange to listen in.

The categorisation of systems where interception is and is not lawful certainly seems odd, and one wonders whether the blanket exemption of Closed systems was intended or not. Certainly, if the requirement for a Private system to be attached to a Public one were removed (bringing its definition into line with common sense) there would be little effect on the rest of the Bill beyond making it unlawful to intercept on what is presently a Closed system (leaving the so-called transit systems unaffected). See amendment C2(1)a.

Scenario 23 - when is a system Public?

There has been an interception on this line, and the question before the Court is whether this was lawful. The matter hinges on whether the telecommunication system was a Closed or a Public one. Justin1 appears for the side which contends that it is Closed, and his twin brother Justin2 appears for the side that contends it is Public.
 

Justin1

With respect, M'Lud, I contend this IS NOT a Public Telecommunication system as defined by S2:(1) of the Act. The line is clearly a "Telecommunication System" under that section, because it facilitates the transmission of communications (those between my clients Chase and Dodge in this present case). The provision of access to, and facilities for making use of, that Telecommunication System to the employees of Chase and Dodge constitutes a "Telecommunications Service" as defined by that section. Who provides this service? Why, Chase and Dodge, of course, because they administer it, they determine who (their employees in this instance) may use it, and the purposes for which it may be used, and they have made arrangements to connect the line into their internal networks. Because Chase and Dodge do not offer this service to the public, nor even to a substantial section of the public, it is not a "Public Telecommunication Service", as defined under that section. Therefore, this particular Telecommunication System (even though it forms a part of the wider Telecommunication System operated by British Telecom, as envisioned by the definitions) is not a "Public Telecommunication System", because the service it provides is not a Public Telecommunication Service, as required by that section. Neither is it, as it so happens, a "Private Telecommunication System", as the Act is currently worded, because it is not connected to a Public Telecommunication System (but if it had been, it would have been).

Justin2

With respect, M'Lud, I contend this IS a Public Telecommunication system as defined by S2:(1) of the Act. The line is clearly a "Telecommunication System" under that section, because it facilitates the transmission of communications. It forms a part of the wider Telecommunication System operated by BT, as envisioned by the definitions. Chase and Dodge are provided with access to, and facilities for making use of, that Telecommunication System for the purpose of sending communications. Whether the communications are restricted to their employees or not is a matter for Chase and Dodge. My clients British Telecom have provided this service to Chase and Dodge in return for appropriate consideration. My clients can and do provide this service to any member or section of the public who are able and willing to pay for it. Therefore, the service provided is a "Public Telecommunication Service" as defined in that section. Therefore, this particular Telecommunication System is a "Public Telecommunication System", because the service it provides is a Public Telecommunication Service, as required by that section.

So who is right? Answer: they both are; there is no flaw in either of those arguments. The problem arises because there are two services being provided:

1. British Telecom are providing a service to Chase and Dodge
2. Chase and Dodge are providing a service to those who actually use the line (their employees)

Scenario 24 - Methods of interception

It has been suggested by some people that GTAC will be in control, downloading the filtering parameters directly into the boxes in accordance with with whatever warrants and notices are in force. This seems to be contrary to the wording of the Bill, which seems to require that such warrants and notices be served on the ISP (S11:(2), S21:(4)) (the ISP then typing the necessary parameters into the box as indeed the Smith Report implies). Nevertheless, there is considerable disquiet that there might be some intention to proceed in this way (especially as interception of conventional telephone calls currently uses such a procedure).

However, it should be noted that an ISP who permits parameters to be entered into the black box from outside will thereby have

"so modified ... [his telecommunication] system, or its operation ... as to make some or all of the contents of the communication available, while being transmitted, to a person other than the sender or intended recipient of the communication." (S2:(2))

Communications Data

There are, however, weaknesses in the definition of communications data, with the government appearing to take a broader view than the wording may justify. Moreover, it is not entirely clear that the originating computer of a communication is not itself a part of the telecommunication system. I base my understanding on the wording in S2:(1) "for the purpose of facilitating the transmission of communications". I think that was intended to exclude the end points (and S2:(2) gives some credence to this view). It is vital that this be cleared up, because things get much worse if I am wrong, as the following scenario will show. See amendment C2(1)b for an attempt to clarify this situation.

Scenario 25 - What can a notice demand?

1. A notice served on the GPO. "Record and disclose to me the addresses, postmarks, return addresses (if present on the envelope), size and weight of all letters and packets delivered to Bob. Seems legitimate, except perhaps for the size and weight bit, but a lot of extra work for the sorting office.

 
2. A notice served on Isaac. "Record and disclose to me the time, the destination and source addresses, and the size of all IP packets passing through your router destined for the Block [123.234.121.*]". Seems legitimate, except again for the size. It involves running a "sniffer" on the router, which would seriously slow it down if a sizeable proportion of packets was to be caught (note that routers do not normally retain such information, except perhaps for statistical data and sampling for monitoring network efficiency).

 
3. A notice served on Isaac. "Record and disclose to me the time, addresses, etc. and the port numbers of all TCP handshakes negotiated between Bob and Alice and passed through your router. TCP is a protocol one layer above IP. But nearly every IP packet will have a TCP packet contained within it. If Plod gets to know the port number negotiated, he will at once know whether it is email, file transfer, web access, or whatever else that is passing between Bob and Alice.

However, I would submit that this is not communications data. Isaac is contracted with Bob and Alice to deliver unopened IP packets between them. The TCP information was added by Bob, and need not be examined again until it reaches Alice (or vice versa). Thus it should not be regarded as attached to the communication "for the purposes of any telecommunication system" (S20:(4)(a)) unless Bob's and Alice's computers are held to be a part of the telecommunication system. However, it is sometimes the case that parts of the telecommunication system will look inside the TCP part, for example to prioritise different kinds of traffic, or to divert certain kinds of traffic (for example, traffic for a web site to a local proxy server). Thus this is a rather grey area in need of clarification.
 
4. A notice served on Isaac. "Record and disclose to me the time, destination address, source address and length of every email that you deposit in Bob's POP mailbox (or that you store in your mail queue for forwarding to Bob). Also the Message-ID of each such email, and the sites that it passed through on its way (Received: headers). Also the Subject:, Date:, In-Reply-To:, Cc:, Bcc:, etc. headers". Note that this only applies where Bob has contracted with Isaac to provide a mailbox or a mail queue to store Bob's mail until it is convenient for him to dial in. So this one is OK (doubts about 'length' excepted) The source and destination addresses are obviously OK. They are normally contained in the "envelope" which accompanies the email. The other items mentioned are part of the "headers" of the email, so would involve looking inside it. However, the "Received" headers are certainly communications data (they record the route taken by the message so far) and the Message-ID might be if, for example, the operator of the system is in the habit of using it for tracking messages through his system. I would contend that the other headers mentioned are part of the content of the message, and therefore should not be disclosed.

 
5. A notice served on British Telecom. "Record and disclose to me every request for Directory Assistance made by Bob using your 192 service, including which names he asked for and which telephone numbers he was given". No way. That is definitely a "communication" between Bob and British Telecom. An interception warrant would be needed.

 
6. A notice served on Isaac. "Record and disclose to me every DNS request made by Bob to your nameserver ns0.isaac.net". "DNS" is "Domain Name Service", used for translating "www.alice.co.uk" into an IP address of the form [123.234.121.232]. It is essentially the same as the 192 example above, and the same rule should apply, even though the request was made entirely automatically by, for example, Bob's Web Browser.

 
7. A notice served on Isaac. "Record and disclose to me the URL of every page that Bob requests to be downloaded from a Web Site". No, because this involves looking inside Bob's IP packets to get at the TCP information inside (and even at the HTTP information inside the TCP information). So long as it is established that Bob's and Alice's computers are not part of the telecommunication system they can only ask for the IP address that Bob is sending the packets to (but they  presumably know that this is the address of a web site).

 
8. A notice served on Isaac. "Record and disclose to me the URL of every page that Bob requests to be downloaded from a Web Site, using your proxy Web Server". Here, Bob has contracted with Isaac to access the Web through Isaac's Proxy (or more likely Isaac has talked him into doing it to reduce his - Isaac's - telecommunications bill). In this case, the request might be valid (it depends whether the service that Isaac is providing to Bob through his proxy is a "telecommunication service"). An interesting case is where Isaac redirects all port 80 traffic to his proxy whether Bob likes it or not (and without telling Bob). Some ISPs do this, I believe.

1:Yes. 2: Yes. 3: Just Maybe. 4: Yes. 5:No. 6: No. 7: No. 8: Maybe.

In particular, the government have been claiming that logs of accesses to web sites are communications data. I would contend that the wording of the Bill limits this just to who visited which site, and does not extend to the identity of the pages downloaded.

Scenario 26 - What are S21:(3) authorizations for?

Perhaps it is something like the following. Plod has visited Isaac on some pretext.
 

Plod	Nice set-up you have here.
Isaac	Yes indeed. We have to have the most up to date equipment in order to provide a full service to our customers.
FX	Just then, Plod forces open the drawer of Isaac's desk (with a jemmy he happens to be carrying), extracts a paper containing "interesting" communications data, takes out his camera and photographs it.
Isaac	What the Hell do you think you are doing?
Plod	Obtaining and photographing this communications data. I have been authorised, by a person designated by the Secretary of state (S24:(2)), to engage in such conduct in accordance with S21:(3).
Isaac	The Heck you have. You have just committed a criminal act. I shall call the Police.
Plod	I am the Police. And, in any case, S20:(2) of the Act renders my "criminal act", as you choose to call it, "lawful for all purposes".
Isaac	In any case, that is OUR information. You have breached OUR copyright. Let me have the film out of that camera immediately, or I shall sue you in Court.
Plod	No you won't, because S20:(3)(a) explicitly excludes me from any civil liability.

Is this over the top? If so, then what sort of scenario is envisaged by the Bill? More realistically, one could imagine that Plod might try to hack into Isaac's computers searching for communications data, in apparent contravention of the Computer Misuse Act.

But if such conduct is not intended (and I hope it isn't), then what scenarios are envisaged by S21:(3), which seems to allow Plod to obtain communications data without troubling Isaac? Where else is he supposed to get it from?

And how can the Bill be compatible with the ECHR if it permits such abuses?

See amendments C20(2) and C21(3) for an extreme cure and C20(2)a for a less extreme cure.