Yahoo hack

Russia denies Yahoo hack involvement

Two FSB officers were accused of conspiring with two alleged criminal hackers in a Department of Justice indictment announced on Wednesday.

The charges are believed to be the first that the US has filed against Russian government officials.

Yahoo's 2014 breach affected 500 million user accounts.

"As we have said repeatedly, there can be absolutely no question of any official involvement by any Russian agency, including the FSB [intelligence agency], in any illegal actions in cyberspace," said spokesman Dmitry Peskov.

Yahoo hack: Should I panic?

But should you be worried - and what can you do to protect yourself in the future?

"Don't panic," security expert Graham Cluley told the BBC, although he does add that there are plenty of reasons to be concerned.

People might suppose the breach is unlikely to affect them because the attack happened three years ago and there was no widely reported abuse of the data in the meantime.

However, hackers might have targeted users' emails.