Marina del Rey’s TeleSign, a mobile phone authentication service, has raised $40 million in a Series B round led by Illinois private equity fund Adams Street Partners.

Also participating in the round were New York’s March Capital Partners and existing investor Summit Partners of Mumbai.

TeleSign’s “Mobile Identity” platform is designed to protect Internet, mobile app and cloud networks from suspicious users. It verifies users by associating a valid mobile phone number with every user account.

TeleSign Chief Executive Steve Jillings said in a statement that the 200-employee company is profitable and has doubled revenue each year for the last four years. The company claims 500 clients in more than 200 countries, servicing some 3.5 billion accounts.

“This capital,” Jillings said in the release, “gives us additional resources to expand quickly and strategically into new markets, innovate rapidly and move toward our goal of a public offering.”