Mr A was caught trying to procure a 10-year-old child for sex. Police found in his possession a number of computer files. They almost certainly contained illegal images and further damning evidence. They may also have contained clues. But officers were unable to read them because they were encrypted. Mr B was found with a large number of deeply disturbing images of children, though they stopped short of showing sexual activity. Police discovered them by piercing the protection with which he had tried to hide them on his computer. But they could not read other, perhaps more incriminating, files because they were encrypted. Mr C was charged with possessing sickening images. Encrypted files suggested that he possessed even worse. But police could not read them. In all cases the suspects refused to reveal, or claimed to have forgotten, their passwords.

The internet has transformed life for billions, making the once time-consuming swift and the once complex straightforward. Unfortunately the beneficiaries include paedophiles who now have a frighteningly easy vehicle with which to peddle the most depraved and exploitative material that would turn the stomachs of those unfortunate enough to come across it. The advance of computer technology now makes it cheap to render such material inaccessible, even to experts in software code-cracking. This is a problem that directly affects the safety of Britain’s children.

In recent years, police investigators have run up against encrypted data with increasing frequency. Even if they succeed in getting into protected files, they may be unable to comprehend the contents without a second key. This is more than frustrating when a suspect is in custody and the clock is ticking until he must be charged or released. A dangerous man could be allowed home.

The Regulation of Investigatory Powers Act 2000 allows police to charge a suspect who fails to unscramble suspicious computer files. If convicted, he faces up to two years in prison. Yet this provision has never been implemented because ministers were advised it was not immediately required. The pace of change over intervening years has made this decision look complacent, and the Home Office is rushing to catch up. Officials want to increase the potential prison term for non-cooperation, understandably believing that a paedophile will accept a two-year jail term rather than the ten years he would receive if his encrypted files were made public.

Punishing silence is a dangerous concept and should be rejected in all but severe cases. But the consultation paper circulated by the Home Office sets out the hurdles, designed to protect the innocent, which prosecutors would have to jump. For a suspect to be charged and face a prison term of more than two years for failing to unlock computer files, he would have to be a convicted paedophile; his computer would have to contain indecent pictures of children; or there would have to be evidence that he had communicated the encrypted information to someone else. The court would have to be satisfied that the encrypted data was likely to contain illegal images of children. The battle against paedophiles, like that against money-launderers, has been made more complicated by the internet. It is reasonable that law enforcement acquires stronger powers to fight back.

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