Digital identity authentication company Payfone has partnered with O2, a U.K.-based mobile network operator. The initiative aims to protect mobile users from digital fraud, including cyber-hacks, account takeover attacks, SIM swap attacks, and other forms of fraud.

The two are collaborating on Payfone’s Instant Authentication for Mobile, a behind-the-scenes, identity verification solution that enables enterprises to authenticate their clients quickly and securely by using a Trust Score that is generated by analyzing millions of digital signals against multiple authentication factors. One of those factors is real-time authentication from O2, which relies on a mobile phone and does not require the user to switch between channels, such as in two-factor authentication.

Payfone CEO Rodger Desai said, “Payfone is already on track to authenticate 50,000,000 transactions per day in the United States, and extending our capabilities into the United Kingdom is a major milestone for us as we continue our expansion into 35 worldwide markets.”

Originally a mobile payments company, Payfone was founded in 2008. The New York-based company has since pivoted to focus on authentication solutions, adopting the motto, “Delight users. Defeat hackers.” Payfone, whose technologies are currently used by six of the top 10 U.S. banks, processes millions of signals per day to authenticate and score transactions; the company currently authenticates 10 million transactions per day. Last spring, Payfone announced it would power mobile ID authentication for Zelle.