In the UK:

In early November about 30 animal rights activists are understood to have received letters from the Crown Prosecution Service in Hampshire inviting them to provide passwords that will decrypt material held on seized computers.

The letter is the first stage of a process set out under RIPA which governs how the authorities handle requests to examine encrypted material.

Once a request has been issued the authorities can then issue what is known as a Section 49 notice demanding that a person turn the data into an “intelligible” form or, under Section 51 hand over keys.

Although much of RIPA came into force many years ago, the part governing the handing over of keys only passed in to law on 1 October 2007. This is why the CPS is only now asking for access to files on the seized machines.

Alongside a S49 notice, the authorities can also issue a Section 54 notice that prevents a person revealing that they are subject to this part of RIPA.