"Social networking website LinkedIn is investigating claims that over six million of its users' passwords have been leaked onto the internet.
Hackers posted a file containing encrypted passwords onto a Russian web forum.
They have invited the hacking community to help with decryption.
LinkedIn, which has over 150 million users, has not released a formal statement, but tweeted: "Our team is currently looking into reports."
http://www.bbc.co.uk/news/technology-18338956