Zscaler, the cloud-based managed security service startup, has raised a $100 million Series B at a valuation exceeding $1 billion, nearly tripling its total previous funding as the company races to stake out market share in the fast-evolving security space.

An IPO could be coming in the next 12 to 24 months, Zscaler CEO Jay Chaudhry tells The Wall Street Journal.

Zscaler operates more than 100 data centers around the globe, which it uses to provide a remote filtering gateway between a company's end users and the public Internet. The company's customers include United Airlines, Humana, NBC, and National Health Services of the UK.

The new investment comes less than a month after enterprise endpoint security firm CrowdStrike raised its own $100 million round, signaling that VC appetite for cloud-delivered security remains strong. Last year, the cloud managed-security market hit $7.2 billion worldwide, and it is predicted to overtake on-premises security within three years.