Adam Adler: EncroChat: Appeal court finds ‘digital phone tapping’ admissible in criminal trials
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Appeal Court decides EncroChat-encrypted phone records can be used in criminal trials. Critics say the decision means phone tapping no longer has a ‘clear meaning in the digital age’
Judges have decided that communications collected by French and Dutch police from the encrypted phone network EncroChat using software “implants” are admissible evidence in British courts.
Police have made more than 1,000 arrests in the UK after the EncroChat phone network was compromised by French and Dutch investigators.
UK law prohibits law enforcement agencies from using evidence obtained from interception in criminal trials.But three judges found on 5 February 2021 that material gathered by French and Dutch investigators and passed to the UK’s National Crime Agency (NCA) were lawfully obtained through “equipment interference”.
“Today’s verdict implies that intercepting, or ‘tapping’ – copying other people’s live private calls and messages – has no clear meaning in the digital age,” said Duncan Campbell, who acted as a forensic expert in the case for defendants, speaking after the verdict.
“If upheld, the ruling appears to mean that tapping is only now tapping if a radio, cable or optical signal is split and copied, but not if data is copied from temporary memory. The consequences from this will be significant,” he said.
Computer Weekly is able to report legal arguments around the case for the first time today following the removal of some previous reporting restrictions imposed in the case.
Ban on intercept evidence
Historically, the UK has prevented the use of intercepted communications as legal evidence in court and has restricted its use to intelligence gathering in order to protect the secrecy of surveillance methods.
This contrasts with most other countries, including France and the Netherlands, which routinely permit the use of intercept material in court.
However, the Investigatory Powers Act 2016 – known as the Snoopers’ Charter – also allows communications obtained from mobile phones and computer equipment to be used in evidence, if they are obtained by “equipment interference” – equivalent to hacking a computer.
“It would appear that Parliament has decided that the need to keep the techniques used in the interception communications secret does not extend to techniques used in extracting data from equipment even if they may recover communications,” the judges wrote.
Was the communication stored when intercepted?
The three judges said that the question they needed to answer to determine the admissibility of messages from EncroChat as evidence was whether the communications were stored “in or by the system” at the time they were intercepted.
They dismissed arguments from expert witnesses that law enforcement obtained messages from EncroChat phones while the communications were being transmitted, rather than in storage.
Lord Burnett of Maldon, Justice Edis and Justice Whipple found that while the experts had an important role in explain how a system works, they had “no role whatever in construing an Act of Parliament”.
“They appear to have assumed that because a communication appears in RAM [computer memory] as an essential part of the process which results in transmission it did so while ‘being transmitted’,” they said. “That is an obvious error of language and analysis.”
The judges compared the transmission of a message on EncroChat to sending a letter. That requires a letter to be written, put in an envelope, have a stamp attached to it and to be placed in a post box. “Only the last act involves the letter being transmitted by a system,” they said.
The judges said it was not necessary for them to define exactly where transmission starts and ends: “We do not accept that transmission of the communication started when the use pressed ‘send’.”
They added that data taken from the EncroChat phones, was “not what has been transmitted, but a copy of it or what, in older forms of messaging, might be described as a draft”.
The appeal court decided that “all forms of storage are caught by the Investigatory Powers Act, whether or not they enable the intended recipient to access the communication,” said Campbell.
Data in a type of communication such as a mobile call typically spends 99.9% of its transmission time at rest in some format, in hundreds of memory storage locations, in dozens of en-route devices, he said.