In a significant decision (R v S and A [2008] EWCA Crim 2177) the court has ruled that a defendant in criminal proceedings cannot rely on the ‘right of silence’ to refuse to give up a password which will allow access to encrypted information held on his or her computer.

The ruling means that if material has come lawfully into the possession of the Police, failing to make that material accessible to them is an offence. Where the failure involves matters of national security, the result may be imprisonment for up to five years.

The decision confirms that data held on computer is treated as essentially the same as written material – the right not to self-incriminate does not apply to evidence which has an existence independent of the person involved. The right of silence is a strictly personal right.