The Uber cybersecurity executive who was reportedly fired for his role in attempting to cover up a massive data breach last year is joining internet security start-up Cloudflare.

Joe Sullivan, who also previously worked at Facebook, wrote in a blog post on Wednesday that he's joining Cloudflare's security team. A spokesperson said in an email that he'll be filling the role of chief security officer and leading the group.

"I've had the good fortune to serve on some of the best Internet security teams in the world at eBay, Facebook, and Uber — and have still fallen short of reaching an ideal state of security," Sullivan wrote in the post.

Cloudflare's technology speeds up and protects websites from outside attacks. The venture-backed company joined the billion-dollar start-up club in 2012 and last year hired a new finance chief from Symantec to start readying an IPO. CEO Matthew Prince told Bloomberg at the time that he was aiming to take the company public by mid-2018.

Sullivan said he chose Cloudflare because the company matches his passion for "securing the whole internet," by providing free versions of its product for website operators and for other projects focused on privacy and connectivity.

Sullivan is best known for his security missteps in his role as Uber's chief security Officer, a position he held from mid-2015 until last November. He was fired after the disclosure of a breach that affected the data of more than 57 million riders and hackers. To cover up the breach, Sullivan reportedly spearheaded an operation that paid hackers $100,000 to delete the data.

In a later story, Sullivan disputed the claim that he was involved in a cover-up.