8.1 Any discussion about electronic evidence in the digital era must now include reference to encryption. This is an increasingly important issue for law enforcement authorities where criminals use strong encryption to thwart the legitimate investigation of officers.¹ It is important to note at the outset that encryption itself is neutral. It is used for legitimate as well as prohibited reasons. Indeed, e-commerce as we know it could not exist without encryption, since it is encryption that makes purchasing on the Internet or a mobile device safe, without fear that our payment details can be intercepted during transmission. However, in this chapter we will be primarily concerned with those who use encryption to hide material.

Encryption

8.2 Encryption is a form of cryptography. It is about disguising the contents of a message or file. Encryption (or enciphering) is the process by which a plaintext (or cleartext) message is disguised sufficiently to hide the substance of the content. As well as ordinary text, a plaintext message can be a stream of binary digits, a text file, a bitmap, a recording of sound in digital form, audio images of a video or film, or any other information. When a message has been encrypted, it is known as ciphertext. The opposite procedure – that of turning the ciphertext back into plaintext – is called decryption (or deciphering). An encryption scheme usually uses a ‘key’ to encrypt and decrypt the message. Data that is encrypted properly can be virtually impossible to decrypt. It is an art that has been practised for thousands of years,¹ but digital technology has revolutionized it. By way of example, consider the message ‘The Eagle is Alive’. The difficulty with transmitting a message in plaintext is that anybody who sees the message knows its content. They may not, of course, know its meaning, but often the actual content of the message is problematic (for instance if the message is a photograph, then you may not want people to see the image). Encryption turns the message into a code that hides the meaning. So, for example, the message ‘The Eagle is Alive’ may be shown as ‘WEK85%LSc43*4lzqnc782’. If someone obtains that message, she will have no idea what this means. Indeed, she will not even know how many characters are in the original message. As digital media, including pictures and sound files, are simply binary data, it means that anything can be encrypted, with the encrypted binary file appearing to have completely random data. A more detailed technical description of encryption is provided in Chapter 1.

Methods to obtain encrypted data

8.3 As noted, to decrypt encrypted text and render it into plaintext requires a key. In complex environments this could be an algorithm, complex data, a dongle (a physical device with a computer chip contained within it) or even biometric measurements,¹ but in most instances it is a code or password. All forms of keys are recognized in the statute that regulates the exercise of investigatory powers to acquire the means by which encrypted electronic data may be decrypted or opened.² For the purposes of this chapter, we will be restricting our analysis to passwords, because they are the most common key used in personal encryption.

Breaking the encryption without obtaining the key

8.4 It is not always necessary to use the key to convert the encrypted material into plaintext. Some examples include:

8.5 Most encryption programs are extensively tested, which means that vulnerabilities are rare. Installing keylogging software is difficult in the era of multiple devices, high-quality firewalls and anti-virus software; the installation of such software by authorities may itself also be illegal. The era of solid-state memory and cloud storage means that encryption can be near-instantaneous. While entering a house requires a legal warrant, it is also high-risk because if a drive is removed, or a connection to the cloud is broken, the plaintext contents can be programmed to be immediately encrypted. Thus, in many instances there is insufficient time to gain entry before the suspect can do any of these things.

Obtaining the key

8.6 A more productive way of breaking the encryption is to identify the key. Let us assume that the police wish to obtain the key from a person they suspect of committing a crime, whose documents are protected by encryption. The police could obtain it in the following ways:

8.7 The fifth option – compulsion – has two possible alternatives. The first is torture, which is illegal in most countries, or the second is through a legal requirement to comply. Usually, this is backed by penal sanction. It is this latter method which has begun to be adopted by countries, although subject to dissenting opinions.

Compelling disclosure in England and Wales

8.8 England and Wales became one of the first jurisdictions to (controversially) introduce specific powers to allow the police to compel the disclosure of a password. The powers are set out in Part III of the Regulation of Investigatory Powers Act 2000 (RIPA). Alongside RIPA, a Code of Practice is issued under the authority of the Act.¹ The latest version was published in 2018.² The Code expands on the rules and procedures set out in RIPA 2000, providing greater certainty to investigators, judges and suspects in understanding how the disclosure powers under the Act will be exercised.

Protected information

8.9 At the heart of the RIPA provisions is the concept of ‘protected information’. This is defined in s 56(1) as:

8.10 Encrypted data would be the most obvious example of ‘protected information’, although the provisions in RIPA are wider than this.¹ There are three powers contained in RIPA 2000 that relate to protected information:

8.11 These powers are considered below. While the first two will lead to the disclosure of information in an intelligible form, the first differs in that it does not technically require the surrendering of the key. It suffices that the person produces the data in an intelligible form. Thus, for example, if there were other documents that were encrypted that were not relevant to the crime, the police would not see them. However, in many instances it is unlikely that the police would be content with an assurance that other documents are not relevant and, instead, they will require the key to be disclosed, which will either provide access or allow the encrypted material to be rendered intelligible. In essence, the difference is who does the decryption. In the first scenario it is the suspect, whereas in the second scenario it will be the relevant investigator, or a nominated person.

Notice requiring disclosure

8.12 Where a suspect does not voluntarily provide her key, or where the police are unable to identify the key using the techniques discussed above, they may seek to serve a notice requiring disclosure of either the information sought or the key. The police can only do so with the permission of the National Technical Assistance Centre (NTAC).¹ NTAC is a government unit that became part of GCHQ (Government Communications Headquarters) in 2006, and has specialist officers dedicated to decrypting ciphertext, including through brute-force attacks and other technical solutions. NTAC will determine whether the encryption is known to NTAC and can be circumvented without the need to invoke RIPA 2000. Where they cannot, NTAC will determine whether the case is appropriate for application for a notice under s 49.

8.13 The power to require disclosure applies where protected electronic information comes into the possession of an officer¹ as a result of exercising a statutory power² or by other lawful means.³ In order to serve such a notice, s 49(2) provides that a person who has been authorized to give permission must have reasonable grounds to believe:

8.14 The person who is authorized to give permission is a circuit judge or a district judge (Magistrates’ Court).¹ Judicial permission recognizes the sensitivities of compelling the disclosure of protected information and provides reassurance that there is independent scrutiny on the grounds set out above. However, it should be remembered that the judge need only have reasonable grounds to believe the criteria is met, and this is a relatively low threshold.² The purposes mentioned above include the interests of national security, the purpose of preventing or detecting crime and the interests of the economic well-being of the United Kingdom.³ It is notable that it is crime, and not serious crime, which is a threshold required for some types of investigatory powers.⁴

8.15 Proportionality is a concept that is now well understood by the courts. Proportionality is best thought of as requiring ‘reasonableness between the objective sought and the means used to achieve that end’.¹ It requires a balance to be struck, ensuring that a measure is not disproportionate to the aim. It requires an examination of alternatives, but does not necessarily require that the least intrusive method always be chosen.² The Code of Practice suggests several aspects of proportionality that the judge should consider:

8.16 The last bullet point realistically does not add much more than the final requirement contained in the Act – that it is not reasonably practicable to obtain the information by other means. It is somewhat strange that it is included on the face of the legislation given that the consideration of alternatives is an important part of proportionality. However, its inclusion perhaps reflects the view that Parliament expects the alternatives to be seriously considered, with a s 49 notice being issued only where there is no real alternative.

Possession of a key

8.17 A person having possession of information or a key to protected information, is defined in s 56(2), RIPA 2000, as follows:

8.18 Three different scenarios exist under this definition:

8.19 In the second and third scenarios, a person may be deemed to have a key, although he does not have the key himself. This is a fairly important provision, because the managerial officers of an organization, whatever the legal form the organization takes, are the ones responsible for the proper management of the private key, rather than the operational staff members.¹ Where the relevant ciphertext is to be found on a company’s device, it would therefore make sense to serve the s 49 notice on an officer or senior manager of the organization, because she will have the power to order compliance by another.

Form of the notice

8.20 The form a disclosure notice is set out in s 49(4), RIPA 2000. It must, among other things, describe the protected information to which the notice relates;¹ specify the grounds upon which the disclosure is believed to be necessary;² specify the time by which the notice is to be complied with,³ which must allow a reasonable period for compliance, depending on the circumstances of the case;⁴ and specify the disclosure required and the form and manner in which it is to be made.⁵ Where there is a cost to complying with a s 49 notice, s 52 provides for the Secretary of State to make an appropriate contribution towards such costs, although it is the investigating authority that ultimately bears the burden of paying these.⁶

Disclosure of protected information and keys

8.21 Where a person is served with a s 49 notice requiring the disclosure of protected information in an intelligible form, she may ether provide the key or use it to render the encrypted material into an intelligible form,¹ unless the notice states that she must surrender the key. The Code of Practice specifically notes that rendering into an intelligible form means returning the data to the state that it was in before encryption was applied, even if this means that there is other protection that might prevent someone from reading it immediately.² Consider an example:

8.22 There may be times when the person to whom the notice is directed does not have the key, or cannot gain access to the key. In such instances, she must give up what keys she actually has, although she does not have to disclose every key she has in her possession.¹ It follows that where a notice is to be served on a body corporate or a firm and it is obvious that more than one person may be in possession of the key, the notice should be directed to a senior officer, partner or senior employee.² However, where it is considered that the circumstances are such that the purpose of the notice would be defeated if it were to be served on the most appropriate person (for instance, she may be the subject of an investigation), then the notice may be served on another individual.³

8.23 An exception is created as regards the disclosure of keys that are used for generating electronic signatures. Section 56(1) RIPA 2000 defines an ‘electronic signature’ as:

8.24 Where a key is used only for this purpose, it does not have to be disclosed in response to a notice, provided it has in fact not been used for any other purpose.¹ It might be useful to recall that a key pair has more than the single function of producing an electronic signature. The same key pair can be used to encrypt a message, depending on the algorithm used.

8.25 However, this exemption may be narrower than it seems. In a commercial context, where more than one person may properly have access to a key, the person served with the notice may not be able to be sure that a key, despite being intended for signature purposes, has never been used to decrypt a message encrypted with the corresponding public key (there is no disclosure obligation if the key ‘has not in fact been used for any … purpose [other than that of generating electronic signatures]’).¹ Although it will be for the prosecution to prove that a key has been used for such a purpose (that does not involve generating electronic signatures and is therefore subject to seizure), the mere assertion of this fact by the person demanding access to the key would place the recipient of the notice in a difficult position to prove a negative in resisting the demand.

Failure to comply with a notice

8.26 Where a person knowingly fails to make the disclosure required by the notice, he commits a criminal offence.¹ Section 53(2) sets out an important presumption of possession of the key:

8.27 An evidential burden is placed on the recipient. This requires her to adduce ‘sufficient evidence of the fact … to raise an issue’.¹ This does not mean she needs to prove that it was not in her possession. Instead, she must adduce some evidence (including through cross-examination) to show that it is not just a hypothetical argument.² Once such evidence is adduced, the prosecution must disprove the assertion beyond all reasonable doubt.³

8.28 A defence exists where a person can show that ‘it was not reasonably practicable for him to make the disclosure required by virtue of the giving of the section 49 notice before the time by which she was required, in accordance with that notice, to make it’ but only if ‘[he] did make the disclosure as soon after that time as it was reasonably practicable for him to do’.¹ Unlike the presumption of possession of the key, this imposes a legal burden on the defence. Thus, the defendant must prove, on the balance of probabilities, that it was not reasonably practicable to disclose the key or data in the time frame required. It only applies if she subsequently makes disclosure and that this was when it was reasonably practicable to do. Accordingly, it would not assist those who continue to refuse to disclose the key.

8.29 A person who honestly does not know the key, or cannot remember it, would not commit the offence, as she must knowingly refuse to surrender the key. If she does not remember the key, then she cannot surrender it. Whether it is credible that she has forgotten it is a matter of fact for the jury. In many instances, forensic data will be important here. While forensic software cannot say what is in an encrypted file, they can often tell when it was last viewed. If a person has been viewing the encrypted data just before the notice under s 49 is served, it is unlikely that a jury would consider it feasible that she has now forgotten the key.

Sentencing

8.30 The offence under s 53 is triable either in the Magistrates’ Court or the Crown Court. The penalty depends on what it is believed the encrypted data contains. Where it is a case of ‘national security’ or ‘child indecency’, the maximum penalty on conviction is five years’ imprisonment;¹ otherwise it is two years’ imprisonment.² A case is a ‘national security case’ if the application made under s 49 stated that the case was ‘in the interests of national security’.³ Similarly, a case is a ‘child indecency case’ if it was stated in the s 49 application that the applicant believed the suspect was involved in the taking, making, distribution or possession of indecent photographs of a child.⁴

8.31 It should be remembered that the threshold for applications under s 49 is reasonable belief. Accordingly, a suspect is at risk of the higher sentence purely because a judge is satisfied that there is reasonable belief that the encrypted material poses a threat to national security or consists of indecent photographs of children. Reasonable belief is a low threshold and is significantly below the standard of proof ordinarily required for higher sentences. For example, where there is a dispute between the prosecution and defence over the circumstances of a guilty plea, the matter is normally resolved in a ‘Newton Hearing’,¹ where the prosecution must prove its version of the facts to the ordinary criminal standard.²

8.32 At issue might be whether the lower threshold can be justified. At first sight it would seem difficult to do so. However, the point of s 53 is that the police cannot decrypt data without the cooperation of the defendant. If they could prove, to the criminal standard, that the encrypted folder contained, for example, indecent images of children, then they would not need to serve a s 49 notice in the first place. While it may be difficult to justify the full criminal standard, it might be possible for the prosecution to prove a lower standard, for example on the balance of probabilities, through, for example, circumstantial evidence (email messages, IP traces etc.) that indicates the contents of the encrypted material.¹ Presumably, the higher penalty can only be used where it is not known what the contents are. Consider an example:

8.33 The Crown Prosecution Service (CPS) may still wish to proceed with the prosecution under s 53 because the suspect has failed to comply with the s 49 notice. A literal reading of s 53 would mean that S is liable for up to five years’ imprisonment, because the grounds for seeking the notice will have included reasonable grounds for believing that S was hiding indecent photographs of children. As this is now known not to be true, S can only be sentenced to a maximum of two years’ imprisonment. For this reason, the courts adopt a strict approach to s 53 cases. In R. v Cutler (Barry George)¹ the Court of Appeal held:

8.34 This is an important point. Encryption puts evidence beyond the reach of law enforcement authorities and prosecutors. It means the full extent of the criminality cannot be ascertained, and the courts must consider this seriously. If s 53 is proven, it is a deliberate attempt to try and conceal evidence from the competent authorities, and this must merit harsh sanctions.

8.35 The seriousness of the offence is perhaps reflected in the comments of the Court of Appeal in R v Padellec (Pierre).¹ The appellant entered a plea of guilty to an offence under s 53. He came to the attention of the police as a possible acquaintance of a person known to be involved in the trafficking of children. His computer (which included an encrypted folder) was recovered, and while no indecent images of children were found, search terms relating to indecent photographs were found. The appellant alleged that he purchased the encrypted device in Belgium and had no knowledge of the key. Following negotiations, a basis for the plea was tendered and accepted by the Crown. This was as follows:

8.36 The importance of the third basis of plea is that it states the defendant did not obtain access to the images of the very worst forms of indecent photographs of children, and which would lead to more severe sentencing.¹ The judge accepted the plea, but suggested that he did so with reluctance. The Court of Appeal was scathing about the basis of plea. In giving judgment, Collins J said:

8.37 If the defendant had not viewed, or stored, images that constituted the most serious examples of indecent photographs of children, then he could have proved this by allowing access to the device. Instead, the prosecution (and the judge) decided that the defendant could admit that he had looked at illegal content but could also keep the details of this illegality secret. The Court of Appeal, quite rightly, considered this an affront to justice. They stated, correctly, that in the absence of an explanation, an assumption of the worst-case basis should be made and the person be sentenced accordingly. To avoid this, the defendant could simply provide access to the images to allow their proper classification. This does not breach the presumption of innocence as the offence itself relates solely to the provision of indecent photographs of children. The defendant conceded this. Sentencing is separate to ascertaining guilt, and it must be right that it is appropriate for the court to take into consideration the refusal to show the images to the court.

Obligations of secrecy and tipping off

8.38 There is a power to attach a secrecy provision to any disclosure requirement.¹ This will require the person to whom the notice is given, and every other person who becomes aware of its contents, to keep the giving of the notice, its contents and the things undertaken in responding to it, a secret.² Breach of this requirement is punishable by a maximum of five years’ imprisonment,³ which is a heavier sentence than that which can be imposed on someone under s 53, save where it is a national security or child indecency case. Several defences exist to this offence, including:

8.39 In all cases, a legal burden is placed on the defence: it must prove the salient facts on the balance of probabilities. Where the defence is that a disclosure has been made to, or by, a professional legal adviser, the defence does not apply where the purpose of the disclosure is to further any criminal purpose.¹

8.40 It should be noted, however, that the effectiveness of the ‘tipping off’ offence is debatable. It might be possible for a person to sign off her email correspondence with a disclaimer, such as ‘I will always explain why I revoke a key, unless the UK government prevents me using the RIP Act 2000’. Using this qualification, let us assume that a correspondent revokes a key. If the correspondent is asked for the reason and she replies that she cannot give one, it is doubtful if she can be convicted of the offence of tipping off, though this is exactly what she has done. There is no suggestion that a disclosed key cannot lawfully be revoked.

Circumventing the procedure

8.41 It has been held, albeit in a first-instance Magistrates’ Court decision, that RIPA 2000 is the only way that the authorities can compel access to encrypted data. Lauri Love is a UK citizen who was a member of the Anonymous hacker collective.¹ He was accused of hacking into US government sites and stealing information.² The US government requested his extradition and the National Crime Agency (NCA) arrested him, exercising a warrant to seize his computers. The computers were found to be encrypted, and a notice under RIPA 2000 s 49 was served, requiring him to disclose either the key or render the information intelligible. He declined to do so. The USA sought his extradition, but this was ultimately refused by the English courts, in part because of his mental health, but also because he could be tried for the offences in England and Wales.³ To date, no criminal proceedings have been brought against him.

8.42 Love applied to the Magistrates’ Court to have his computer equipment returned.¹ The court declined to order its return unless he provided a detailed list of the contents of the computer, something he has refused to do. The NCA made an application that Love be directed to provide the keys to the encryption.² The district judge, however, held that this was not a proper use of the court’s jurisdiction. The judge held that RIPA 2000 provided the statutory procedure to secure access to encrypted data. The decision of the district judge was undoubtedly the correct one. In essence, the NCA was seeking to use civil proceedings to gain access to the key, rather than rely on RIPA 2000. Had the application succeeded, the NCA could have sought to use contempt of court proceedings to require compliance with the direction, which could ultimately have led to the imprisonment of Love. However, as the judge noted, the correct avenue to enforce s 49 is to bring a prosecution for non-compliance under s 53.

8.43 While Love defeated the application, a strange impasse now exists, because his application under the Police (Property) Act 1897 was also rejected. He refused to discuss what was encrypted, hence the district judge held that its continued seizure was required. The police have the right to retain seized material to prevent it from being concealed, lost, damaged, altered or destroyed.¹ Not unreasonably, it was thought there was reason to believe that Love may seek to destroy any incriminating evidence contained on the machine should it be returned to him.

8.44 The reluctance to prosecute Love is somewhat puzzling since, on the face of it, it appears that Love did breach s 49. For whatever reason, the NCA has chosen not to prosecute. As Love refuses to comply, the NCA are left with computers that they cannot obtain access to (although presumably NTAC is trying to override the encryption) and Love is allowed to ignore the requirement to surrender the encrypted information. This demonstrates that while it is often said that RIPA compels the disclosure of encryption keys, technically it does not. Ultimately, all the legislation can do is to ensure that those who refuse to disclose the key or render information intelligible can be punished. The encrypted material, however, remains beyond reach.

The privilege against self-incrimination

8.45 Compelling someone to provide a key has proven to be controversial. In most cases, the key is a password, and this password might have been thought of by the suspect, although random password generators are also used. It has been suggested that compelling the disclosure of the key infringes the common law privilege that someone cannot be compelled to incriminate herself. It is the fact that the password is the product of one’s mind, and can only be released through testimony, that raises this argument. A key could be something physical, including another piece of code, a biometric measurement or, for example, a dongle (a piece of technology usually including a chip). Requiring a person to hand over, for example, a dongle to unlock the encryption would not necessarily breach the privilege,¹ because the key is invariably a self-produced password. The remainder of this chapter will explore how compelling the production of the key interferes with the privilege of self-incrimination in three jurisdictions: England and Wales, the USA² and Belgium.³ The position in Canada is considered in brief.

England and Wales

8.46 While the privilege of self-incrimination has long been a creature of the common law,¹ it is also considered to be a fundamental part of article 6 of the European Convention on Human Rights (ECHR).² The Human Rights Act 1998 requires public authorities, including the police and the judiciary, to act in a way compatible with the ECHR,³ and the courts must take account of the jurisprudence of the European Court of Human Rights.⁴

8.47 The first case to challenge the compatibility of Part III of RIPA was R v S (F) and A (S).¹ A third party (H) was made the subject of a control order under the Prevention of Terrorism Act 2005. S, A and H conspired to circumvent this control order by allowing H to move houses. This occurred, but shortly afterwards the police detected his presence. When the police arrived, H and S were in different rooms. S was alone in a room with a laptop. The password to an encrypted file was partly entered. S was arrested, and his premises searched, but nothing that contravened terrorism laws was found. However, the police could not examine the laptop due to the encryption. Later, A was arrested and a laptop was seized from him. Again, there was an encrypted folder on it, and the police were unable to gain access to the laptop.

8.48 Neither A nor S made any comments during their interviews and did not voluntarily disclose the passwords that would unlock the encryption. Both were served with a notice under s 49 of RIPA 2000. Neither complied, and they were prosecuted under s 53. They both entered a plea of not guilty and sought a stay of prosecution, alleging that the notices themselves were incompatible with the privilege against self-incrimination and article 6 of the ECHR. The judge at first instance refused the stay, and A and S appealed to the Court of Appeal.

8.49 The members of the Court of Appeal noted that the submissions of all parties were premised on the basis that incriminating evidence would be discovered if the laptops were examined without encryption.¹ There was no evidence of this, but the appellants conceded that incriminating material may be discovered. The members of the Court of Appeal noted that under both domestic and European jurisprudence, the privilege against self-incrimination was not absolute, and that there were several statutory provisions that overrode it. Thus, the first question was whether the privilege applied in these circumstances. It was held by the judge at first instance that the key was something held independent of the will of the suspect. If that was true, then the privilege against self-incrimination would ordinarily not apply.² The Court of Appeal held:

8.50 The logic behind this argument is that while the password may initially have been the product of the defendant’s mind, it has an independent status once used. If the password was guessed or identified, then the encryption would unlock irrespective of whether the defendant willed it or not. They also noted that the key is neutral. It is not by itself either exculpatory or incriminating – it is simply a piece of information. However, if the contents are incriminating, then knowledge of the key could in itself be incriminating. The court provided the example of an encrypted folder containing indecent photographs of children.¹ The fact that a person knows the key – and this would be shown through complying with the s 49 notice – could be used by the prosecution to show that the offender was in possession of the photographs.² Of course, that depends on the facts. Where the substantive offence does not rely on control, then the possession of the key may not be incriminating.

8.51 Ultimately, the Court of Appeal conceded that s 49 could interfere with the privilege of self-incrimination, but noted that it would only do so if the evidence that is being shielded by encryption is itself incriminating. However, the court opined that material unquestionably exists independent of the will of the individual and, therefore, there is no question of it being protected by the privilege. Thus, the only argument that could be put forward is that it is unfair for that evidence to be put before the court due to the circumstances in which it was found (through complying with s 49).¹ That being the case, the Court of Appeal held that such matters could be dealt by the trial judge under the discretionary power to exclude prosecution evidence.²

8.52 The decision in S and A has not been universally welcomed. This is partly because the logic of the Court of Appeal stretches credibility. Roberts in the Criminal Law Review observed that an encryption key, unless documented, is an ‘intangible “psychological fact”, that is to say, it is information which exists only in the suspect’s memory and that of any other person who might “know” it’.¹ The Court of Appeal would argue that this is not true because the key does exist – it is recorded and used within the encryption algorithm that is unlocked by the password. However, for all practical purposes, it is not. There is a very small chance that the password can be discovered by any other means. Indeed, if the police were able to identify the password other than through compelling the suspect to testify, there would be no need to issue a s 49 notice. As was noted above, it is almost impossible to guess a key when encryption is used properly due to the potentially vast number of possible combinations. Therefore, while in theory the key is independent of the will of the accused, it is, for all practical purposes, a psychological fact and, therefore, probably within the privilege. However, Roberts’ later point is perhaps the more salient. He notes that it does not matter whether privilege was or was not engaged because, following Brown v Stott,² English law recognizes the privilege can be set aside by statute where it is proportionate to do so.³ Given the facts of the case, the national security implications would inevitably mean that displacement was undoubtedly proportionate.

8.53 The issues were further rehearsed in Greater Manchester Police v Andrews.¹ Rather than proceedings under s 53, this was an appeal from the refusal of the circuit judge to authorize a s 49 notice being served. Andrews had previous convictions for the sexual abuse of children, and was the subject of a Sexual Offences Prevention Order. Police arrested him on suspicion of breaching this order, and seized a computer and two memory sticks. Indecent photographs of children were found on the computer, but the memory sticks were encrypted. This meant that they could not be viewed. Andrews refused to provide the passwords or software used to encrypt the devices. The police applied for permission to serve a s 49 notice, but this was refused. The judge stated that requiring Andrews to reveal the key infringed his privilege against self-incrimination, because there was no independent evidence to show that he knew what the key was.² The judge sought to use these facts to distinguish this case from R v S (F) and A (S).³ The Court of Appeal was unimpressed with the logic of the judge. They noted that as the devices were unquestionably found in his possession, that it was not unreasonable to believe that he might know of the existence of the encryption and its key.⁴ The court did not disagree that the privilege might be invoked, and noted once more that the privilege applied only in a limited way (repeating that the key was, in essence, neutral and it simply provided access to non-privileged material that was itself incriminating), and that English law allowed it to be displaced where it was proportionate to do so.⁵

8.54 Section 49 has not been challenged again, and so the legal position now seems relatively settled. As noted at the beginning of this chapter, the power is not exercised particularly frequently. This suggests that the police are only using it where they suspect that encryption is shielding serious criminality. That being the case, it is likely the courts would consider it proportionate that the privilege against self-incrimination is set aside, as they did in R v S and F.

The USA

8.55 The position in England and Wales can be usefully contrasted with the approach taken in the USA, where the Fifth Amendment protects the privilege against self-incrimination.

The Fifth Amendment privilege against self-incrimination

8.56 One of the first cases in the USA to deal with this issue was also cited in R v S (F) and A (S)¹ to illustrate the point that knowledge of the password might be relevant to the privilege against self-incrimination. The case of In re Grand Jury Subpoena to Sebastien Boucher² involved facts arising out of the search of a laptop at the US border with Canada. On 17 December 2006, Boucher and his father entered the US from Canada. A customs and border protection officer found a laptop computer in the vehicle they were travelling in. He opened the computer and switched it on without entering a password. He searched the various files in the computer and discovered approximately 40,000 images, some of which appeared to be pornographic, based on the names of the files. Boucher was asked if any of the files contained abusive images of children, to which he responded that he was not certain. The officer continued to search the files and noticed some files with names that suggested images of a minor engaging in sexually explicit conduct. He then requested the help of another officer, who determined that a number of files contained abusive images of children. Boucher was then read his Miranda rights. He told the second officer that he downloaded pornographic files and indicated that he did not intentionally download images of a minor engaging in sexually explicit conduct and deleted any such images when he came across them. Boucher was given access to the laptop and navigated to the Z drive, to which he obtained access by inserting a password. The second officer did not see Boucher do this. Boucher was subsequently arrested and his laptop was seized. After obtaining a search warrant, the government discovered that the Z drive was encrypted and the investigating authorities could not open the Z drive. A grand jury subpoena was issued for Boucher, directing him to ‘provide all documents, whether in electronic or paper form, reflecting any passwords used or associated with’ his seized computer.³

8.57 Boucher moved to quash the subpoena because, he alleged, it violated his right not to incriminate himself under the provisions of the Fifth Amendment. Whether the privilege against self-incrimination applied in this instance depended on whether the subpoena sought testimonial communication. Both parties agreed that the contents of the laptop computer were not covered by the Fifth Amendment because they were voluntarily prepared and not testimonial in nature. The magistrate court held that requiring Boucher to enter the password would disclose both that he knew the password and that he had control over the files on the encrypted drive.¹ The magistrate therefore concluded that the Fifth Amendment prevented the government from compelling Boucher to provide the password on the basis that it would compel him to display the contents of his mind and thereby incriminate himself.² The government appealed this decision,³ arguing that it was already aware of the existence and location of the information during the border examination (when the officer viewed the contents of some of the Z drive files, and ascertained that they could consist of images or videos of a minor engaging in sexually explicit conduct). On appeal, the district court agreed. The court held that requiring Boucher to ‘provid[e]‌ access to the unencrypted Z drive “adds little or nothing to the sum total of the Government’s information” about the existence and location of files that may contain incriminating information’, and therefore this did not constitute ‘compelled testimonial communication’ and did not breach Boucher’s Fifth Amendment right against self-incrimination.⁴

8.58 The Boucher case is illustrative of compelled decryption cases in the US. A defendant’s Fifth Amendment privilege against self-incrimination is implicated when the police require a suspect to enter a passcode to unlock an encrypted device, such as a telephone or computer. United States courts tend to agree that the act of entering a passcode is testimonial, which activates the privilege against self-incrimination; however, this privilege is not available if the police can show that the testimony would be considered a ‘foregone conclusion’.

8.59 This rule is based on the ‘act of production’ doctrine from Fisher v United States,¹ which was developed in the context of producing documents pursuant to a subpoena. The Supreme Court in Fisher held that the Fifth Amendment privilege against self-incrimination was implicated when the government compelled a suspect to produce documents when the act is both testimonial and incriminating.² The act of production is neither testimonial nor incriminating, however, when it ‘adds little or nothing to the sum total of the Government’s information’ and is therefore a ‘foregone conclusion’.³

8.60 Courts have adopted and applied the act of production doctrine and its foregone conclusion exception to cases of compelled decryption. Courts differ, however, on how the foregone conclusion exception should be applied on two primary fronts. First, courts differ on whether the police must show that they already have knowledge that the suspect knows his passcode, or whether the police must show that they already have knowledge of the encrypted content of the device.¹ In other words, courts differ on what constitutes the ‘testimony’ that must be a foregone conclusion. Second, courts differ on the burden of proof of this foregone conclusion: some courts have required the police to show clear and convincing evidence,² some have required proof beyond a reasonable doubt,³ some have required a showing of facts with reasonable particularity,⁴ and still others seem to gloss over the standard required entirely. This section will survey some of the more influential cases, noting that these jurisprudential splits can only be resolved by the US Supreme Court.

8.61 In the case of In re Grand Jury Subpoena Duces Tecum Dated March 25, 2011,¹ law enforcement agents began an investigation in March 2010 of an individual suspected of using a YouTube.com account for sharing explicit materials involving underage girls. During the course of their investigation, officers obtained several Internet protocol (IP) addresses from which the individual had obtained access to the Internet. Three of the addresses were subsequently traced to hotels. A review of the register in each hotel revealed a common name registered at the hotel at the relevant time, being that of one Doe. Doe was found at a hotel in California, and the police applied for and obtained a warrant to search his room. Seven items were seized, including two laptops and five external hard drives. Examiners from the Federal Bureau of Investigation analysed the digital media but could not obtain access to some parts of the hard drives because they were encrypted with a software program called TrueCrypt.

8.62 Doe refused to provide the passwords to enable the government to open and view the encrypted data, and he also refused to decrypt the data. As a result, he was served with a subpoena duces tecum, requiring him to appear before a grand jury and produce the plaintext of the encrypted files located on the hard drives of his laptop computers and the five external hard drives. Federal prosecutors offered him immunity for the act of decrypting the computer but reserved the right to use any evidence it found on the computer against him.¹ When he appeared before the grand Jury, Doe invoked his Fifth Amendment privilege against self-incrimination to not reveal the plaintext. During the hearing, the forensic examiner testified that he could obtain access to some parts of the hard drives, but he could not know for certain whether there might be data on the encrypted part of the hard drive – indeed, he accepted there might not be any data in the encrypted part of the drives. The district court determined that Doe’s failure to decrypt the relevant parts of the hard drives amounted to contempt of court and committed him to custody.

8.63 On appeal, the Eleventh Circuit Court of Appeals reversed the district court decision and held that the decryption and production of the hard drives was a testimonial act, and thus the defendant could assert his Fifth Amendment privilege against self-incrimination. The court reasoned:

8.64 Further, the ‘foregone conclusion’ exception was not available to the government because it failed to show that it had knowledge of the contents of the defendant’s device. The court noted that:

8.65 In this regard, In re Grand Jury is distinguishable from Boucher in that the government was aware of what was on Boucher’s computer because of his own actions in displaying them to the officers.¹

8.66 While there is wide agreement that the act of production doctrine and foregone conclusion exception apply to cases of compelled decryption, courts differ on what constitutes the testimony that must be a foregone conclusion. The In re Grand Jury court required the government to show that the contents of the suspect’s device would be a foregone conclusion. Interestingly, the Boucher court, while not explicit in its analysis about what testimony must be proven, found that the government knew both the contents of the device and that the suspect could decrypt the device. The Third Circuit Court of Appeals considered a similar case, although it would go on to provide detailed guidance of what type of testimony must be shown to be a foregone conclusion – and in so doing, diverged from the Eleventh Circuit in this regard.

8.67 In 2017, the Third Circuit considered the case of United States of America v Apple MacPro Computer¹ in which the suspect Doe refused to decrypt hard drives that were obtained by police pursuant to a valid search warrant. Along with the hard drives, police also seized a mobile telephone and a MacPro computer. The police were able to bypass the encryption on the MacPro computer and found evidence that Doe had downloaded photographic files constituting images of a minor engaging in sexually explicit conduct. The police suspected that the files themselves were stored on the separate encrypted hard drives that Doe refused to decrypt. Doe argued that the act of decryption would violate his Fifth Amendment privilege against self-incrimination.

8.68 The Third Circuit followed the Eleventh Circuit’s legal reasoning that the act of production and foregone conclusion rules applied to the compelled decryption of devices. Unlike the facts of the case before the Eleventh Circuit, however, the Third Circuit found that the testimony sought by the government from Doe was a foregone conclusion. The court reasoned: ‘the Government has provided evidence to show both that files exist on the encrypted portions of the devices and that Doe can access them.’¹ Among other reasons, the evidence to support this assertion was: the encrypted devices were found at Doe’s residence and he did not dispute his ownership of them, analysts found evidence on the MacPro computer that the user had visited groups that had titles used in child exploitation and had downloaded images known through hashing to be images of a minor engaging in sexually explicit conduct, and Doe’s sister had witnessed Doe unlock the hard drives to view images and videos of a minor engaging in sexually explicit conduct.² Based on these and similar facts, the magistrate had found that the testimony would be a foregone conclusion. The district court and the Third Circuit Court of Appeals both affirmed that conclusion.

8.69 Due to the overwhelming amount of proof against Doe, it could be difficult to ascertain whether the Third Circuit requirement that the testimony must be shown to be a foregone conclusion is simply the passcode or ownership of the devices, or the contents of the device. The Third Circuit had evidence in that case that Doe owned the devices and had decrypted the devices previously, and that the government knew the contents of the devices, all of which qualified as a foregone conclusion. Helpfully, the court added a footnote, that although dictum, is persuasive authority for future cases in the Third Circuit:

8.70 Other cases have cited this dictum by the Third Circuit Court of Appeals in Apple MacPro Computer to hold that the government need only show that the suspect’s knowledge of the passcode is a foregone conclusion.¹ This is consistent with an unpublished opinion of the Fourth Circuit Court of Appeals in United States of America v Gavegnano,² in which the appellant was convicted of receipt and possession of abusive images of children stored on a laptop computer owned by the government and issued to him for the purposes of his work. One of the grounds of appeal was based on the Fifth Amendment, in that he gave the password of the laptop computer to the prosecuting authorities after meeting with his lawyer. The Fourth Circuit rejected his claim, on the basis that ‘Any self-incriminating testimony that he may have provided by revealing the password was already a “foregone conclusion” because the Government independently proved that Gavegnano was the sole user and possessor of the computer’.³

8.71 Nonetheless, other courts have chosen to follow the approach set out by the Eleventh Circuit that requires the government to show, with reasonable particularity, that the contents of the device are a foregone conclusion.¹ In adopting this approach, the district court In the Matter of the Search of a Residence in Oakland, California explicitly rejected the notion that an encrypted device, in this case a telephone, was akin to a safe and that the government’s demand for a passcode is merely the same as compelling a suspect to enter a passcode to open a safe, much like the use of a key.² The court reasoned that ‘[t]‌oday’s mobile phones are not comparable to other storage equipment, be it physical or digital, and are entitled to greater privacy protection’. Quoting the US Supreme Court’s opinion in Riley v California, the District Court considered that a search of a telephone ‘would typically expose to the government far more than the most exhaustive search of a house’.³ Given the primary split between the Eleventh Circuit Court of Appeals and the Third and Fourth Circuit Courts of Appeals, it is possible that the US Supreme Court will, at some time in the future, be asked to clarify the scope of the act of production doctrine and the foregone conclusion exception in the context of compelled decryption of devices by the use of passcodes.⁴ Likewise, courts seem to be split on the issue of whether a forced use of biometric measurements constitutes ‘testimony’ such that the Fifth Amendment privilege against self-incrimination will apply.

8.72 There are several Federal District Courts¹ and at least one State Supreme Court² that have found that compelling the suspect to unlock a device, usually a telephone, with a biometric measurement such as a fingerprint or face, does not constitute testimony such that the privilege against self-incrimination is implicated. As the District Court of Idaho reasoned in the case of In the Matter of the Search of: a White Google Pixel 3 XL Cellphone in a black incipio case, ‘the Government agents will pick the fingers to be pressed on the Touch ID sensor, [and so] there is no need to engage in the thought process of the subject at all in effectuating the seizure’.³ The court in that case compared this act to other compelled displays of physical features that have been allowed by the US Supreme Court, including, ‘putting on a shirt to see whether it fits the defendant; providing a blood sample to test for alcohol content; submitting to the taking of fingerprints or photographs; providing a voice exemplar; and providing a handwriting exemplar’.⁴

8.73 Other courts disagree, however. In United States v Wright, a federal district court in Nevada held:

8.74 Another Federal District Court in Illinois agreed, and cited the Eleventh Circuit opinion in the case of In re Grand Jury Subpoena Duces Tecum Dated March 25, 2011 to support its holding that ‘the connection of a fingerprint to the electronic sources that may hold contraband … does explicitly or implicitly relate a factual assertion or disclose information’.¹ The court rejected the government’s claim that the Fifth Amendment does not apply to the compulsion to submit to fingerprinting, stating:

8.75 Similar to the issue of forced decryption through use of passcodes, the testimonial nature of biometric features used for decryption needs clarification from a higher court.

Bypassing the Fifth Amendment by compelling the assistance of third parties

8.76 Given the limitations of the cases noted above regarding compelled decryption by suspects, governments increasingly seek to compel third party intermediaries, usually technology companies or communications service providers, to provide plaintext data to law enforcement authorities. Perhaps the most famous example of the US government attempting to compel a third party intermediary to decrypt a device is the litigation over an Apple iPhone seized by the FBI in Government’s ex parte application for order compelling Apple Inc. to assist agents in search¹ before the district court of the Central District of California. The US government seized an iPhone 5C believed to have belonged to Syed Rizwan Farook, an alleged terrorist who perpetrated an attack which killed 14 people and injured 22 others in San Bernandino, California. The iPhone was protected by a passcode. Later generation iPhones have their contents encrypted by default, and the passcode acts as the password. Thus, without the password, the FBI was unable to obtain access to the contents of the device. It is also possible to set the iPhone to auto-erase the contents of the telephone if a set number of incorrect passcodes is entered.

8.77 Given these obstacles, the government sought an order under the All Writs Act¹ requiring Apple to assist the FBI in circumventing the encryption.² Contrary to what was reported in most media, the order did not require Apple to break the encryption, but rather Apple was ordered to provide reasonable technical assistance in bypassing or disabling the auto-erase function, enabling the FBI to submit unlimited passcodes to the device for electronic testing and ensuring that the device would not purposefully introduce any additional delay between passcode attempts, essentially enabling a brute-force attack.³ Apple resisted the imposition of the order, arguing that to do so would hand unparalleled powers to the government, which would render data privacy laws meaningless. They argued that any process they put in place could be exploited by others, which meant that the privacy of all its customers would be put at risk.⁴ Ultimately, the FBI were able to obtain access to the device with the help of an unnamed third party, and the litigation was discontinued.⁵

8.78 In a similar case,¹ the government sought an order before a New York court requiring Apple to bypass the passcode security on an Apple device on the basis that such an order would assist in the execution of a search warrant previously issued by the court. The court denied the government’s motion, on the basis that the government had failed to establish that the All Writs Act permitted the relief it sought, partly because Congress had considered legislation that would achieve the same result but had not adopted it. The judge also noted that a court, when deciding whether to take such discretionary action, was required to consider three additional factors:

8.79 The court said that even if the statute did apply, all three discretionary factors weighed against the issuing of the requested writ, and that the application would be denied as a matter of discretion, even if it is available as a matter of law.

8.80 These cases brought renewed attention to the encryption debates between law enforcement authorities who seek lawful access to plaintext data and the information and communication technology (ICT) companies who implement encryption by default for security purposes. In addition to security concerns, these companies also benefit from encryption by shifting control to the user, which limits the abilities of the companies to cooperate with the government. ICT companies can also benefit from appearing to champion user privacy, especially after the Snowden revelations in 2013.¹ After these revelations, both Apple and Google announced they would begin encrypting devices by default.² Around the same time, James Comey, then Director of the FBI, articulated concerns about the growing use of encryption:

8.81 To solve this ‘going dark’ problem, Reitinger argues that ‘permitting law enforcement to compel the production of keys when necessary, with judicial supervision as appropriate, is a minimal accommodation to the need for public security in a world in which criminals have an increasing array of sophisticated tools at their disposal’.¹ It is difficult to think of any other aspect of evidence where a suspect is allowed to wilfully hide evidence of his criminality from law enforcement and for this to be condoned by the criminal justice system. Using encryption, a person can hide thousands of abusive images of children on a device. They could obtain access to them every day but, if they took appropriate precautions,² law enforcement authorities would find it almost impossible to prove that the offence has taken place.³ That is not in the interest of society. This is a point made by Orenstein MJ of New York in his concluding remarks in one of the cases involving Apple:

8.82 Jim Baker, former general counsel for the FBI, was responsible for leading the government efforts to compel Apple to decrypt the iPhone in the San Bernandino case in 2016.¹ In 2019 Baker wrote that his opinion on encryption had changed in light of the serious cybersecurity threats facing the US:

8.83 Baker’s remarks illustrate how the encryption debate has turned in recent years from the ‘false dichotomy’ between security and privacy to a discussion of competing security interests.¹ ICT companies and computer scientists argue that encryption is necessary to protect users from criminals, while law enforcement authorities argue that encryption protects criminals from detection and prosecution. In reality, encryption does both. Privacy advocates and computer scientists argue that criminals will always find a way to communicate anonymously and that measures designed to allow governments to have access to keys or back doors will do more harm to regular users of these technologies.² Computer scientists in particular have raised alarms that any government proposals for ‘exceptional access’ to encrypted systems are ‘unworkable in practice, raise enormous legal and ethical questions, and would undo progress on security at a time when Internet vulnerabilities are causing extreme economic harm’.³ These same computer scientists concluded a report analysing law enforcement proposals for exceptional access with the following observations:

8.84 However, the Encryption Working Group, funded by the Carnegie Endowment for International Peace and comprising former government officials, business representatives, privacy advocates, law enforcement authorities and computer scientists in the US, believe that ‘more common ground is attainable’ if the discussion between participants focuses on the individual ‘component parts’ within the larger umbrella of encryption policy.¹ For example, while encryption for data in transit may raise many of the issues that concerned the computer scientists cited above, ‘some forms of access to encrypted information, such as access to data at rest on mobile phones’ may be possible.² By debating specific types of encryption, data and devices, it may be possible to find a sensible middle ground approach which allows for law enforcement authorities to obtain access to decrypted data without endangering cybersecurity or privacy.³

Canada

8.85 Another perspective to this debate is added by the decision of the Canadian court in R. v Beauchamp.¹ In this case, an unusual application was brought. Rather than the law enforcement agency seeking access to encrypted data, the defence sought an order to require the Crown to disclose a copy of encrypted files located on a hard drive that had been seized by the police. The Crown had not been able to decrypt the files, and as a result had no knowledge of the data that was encrypted. It was agreed that the encrypted information was both potentially inculpatory and potentially exculpatory for the accused parties. The Crown submitted that the encrypted information was beyond its control, and although it was arguably in its possession, it was not in a format that the Crown was able to view. The judge concluded that the Crown was in partial possession and control of the hard drives, but it had no knowledge of the information in the encrypted files. Smith J analysed the position as follows:

8.86 For these reasons, the application for disclosure of a copy of the encrypted files in the hard drives was refused, although the judge indicated that the applicants could, at their option, obtain disclosure of the contents if they provided the password or key to the Crown, and the Crown would then review the material. Had the application been allowed, it would have created an untenable situation. The state would have provided a file that only one party (the defence) could view. The defence would presumably extract the exculpatory evidence without giving the Crown sight of the inculpatory evidence. It is suggested that this decision struck the correct balance, which is to enable the defence to disclose the key so that both parties will have access to the plaintext material.

Belgium

8.87 The Court of Cassation in Belgium¹ has held that Belgian law can require a criminal suspect to disclose their mobile telephone passcode without violating their right to remain silent and to not incriminate oneself, provided the investigating authority can show that the mobile telephone was detected without coercion and that the suspect knows the passcode ‘without reasonable doubt’.² The Belgian Court interpreted the right to not incriminate oneself as guaranteed by the ECHR, the International Covenant on Civil and Political Rights, and Directive (EU) 2016/343 of 9 March 2016 on the strengthening of certain aspects of the presumption of innocence and of the right to be present at the trial in criminal proceedings.³ The court found that the qualified right against self-incrimination would not prevent authorities from gathering evidence that exists ‘independently of the will of the person who has knowledge of’ the passcode.⁴ It held that ‘the main purpose of the right not to incriminate oneself is to safeguard the right to a fair trial by excluding false statements made under duress’.⁵ Because the passcode remains unchanged regardless of whether it is communicated, the court determined that ‘[t]‌here is no risk of unreliable evidence’.⁶

8.88 The court found that the passcode is thus akin to the communication of biometric data, which is a permissible derogation from the right to not incriminate oneself. Even if the passcode reveals information that is subjected to substantial criminal sanctions, the communication of the passcode itself only relates to accessing an ‘already discovered IT system’.¹ Thus, the compelled decryption of a telephone passcode did not violate the suspect’s right to remain silent.

Concluding observations

8.89 Encryption is a fundamental part of modern cybersecurity. Good quality encryption provides reassurance to users that sensitive information can be securely stored. However, it is obvious that a criminal can also use encryption to hide his actions. More than this, encryption allows material to be hidden from everyone else, but remain accessible to the possessor of the cryptographic key. Throughout history, people have hidden files or objects that they do not want law enforcement authorities to find. However, that invariably affects the ability of the owner to use the files or objects. For example, a person could send photographs or physical records out of the jurisdiction where no mutual legal assistance treaty exists. This will keep the data away from investigators, but the owners will not be able to view the photographs or records themselves. Encryption, however, means that the possessor of the key can easily open a file and, for example, look at illegal material at will, while preventing law enforcement authorities from knowing what is being looked at.

8.90 The philosophical basis around the right to self-incrimination is of fundamental importance in any criminal justice system. The difficulty is in establishing a balance between the right not to incriminate oneself when accused by the state, and the rights of victims and society to liberty and security. This is a difficult balance to achieve,¹ and in this chapter we have described how various jurisdictions have approached this problem.

8.91 The balance between the competing security interests implicated by encryption will require continued scrutiny from courts and lawmakers as encryption technologies advance.¹ These issues will continue to affect criminal investigations into a wide variety of criminal conduct.² While the cases explored in this chapter mostly involved criminal offences concerning child sexual abuse materials, law enforcement authorities need to obtain access to encrypted evidence in offences ranging from cybercrime and organized crime to routine investigations into theft, assault and homicide. Thus, we can expect the law concerning access to encrypted data to continue to develop and evolve.