LinkedIn is joining the crowd of Internet services tying account security to mobile phones.
In a change announced Friday, the roughly 225 million users of LinkedIn's online professional networking service can now choose to require a code to be sent to their phones whenever an attempt is made to log in to an account from a device for the first time.
The code sent to the phone is needed to complete the login process. The extra step is designed to lessen the chances of computer hackers breaking into user accounts.
Google, Facebook, Microsoft and Twitter are among other major companies to deploy this two-step verification process.
LinkedIn, based in Mountain View, Calif., had about 6 million user passwords stolen and posted on the Internet in 2012.