Power sockets can be used to eavesdrop on what people type on a computer.
Security researchers found that poor shielding on some keyboard cables means useful data can be leaked about each character typed.
By analysing the information leaking onto power circuits, the researchers could see what a target was typing.
Usefully, said the pair, the six wires inside a PS/2 cable are typically "close to each other and poorly shielded". This means that information travelling along the data wire, when a key is pressed, leaks onto the earth (ground in the US) wire in the same cable.