Marketers will soon have another tool to fight back against ad fraud.

The Interactive Advertising Bureau (IAB) Tech Lab will likely release its spec for ads.cert later this year. This tool—a complement to the previous IAB Tech Lab initiative ads.txt—will give marketers a deeper check against unauthorized ad selling. Confused already? Here’s a primer of what you need to know:

What Is ads.cert?

Ads.cert is an authentication tool that helps marketers determine whether the impressions they receive from an ad exchange belong to the intended website, according to Jim Butler, co-chair of the IAB Tech Lab OpenRTB Working Group and CTO of global supply platforms at Oath.

To authenticate inventory and show how it has moved along the ad supply chain, ads.cert uses cryptographically stamped bid signatures, which give advertisers a clearer view into the inventory they’re buying. Ads.cert helps advertisers verify whether or not the data they receive about an ad call is accurate, according to Amy King, vice president of product marketing at Pixalate.

How Does It Differ From ads.txt?

Launched by the IAB Tech Lab in May 2017, ads.txt is a text file on publishers’ sites that lists all the vendors that are authorized to sell their inventory. Because domain spoofing and arbitrage have plagued programmatic advertising, ads.txt was created to provide ad buyers a tool to check the legitimacy of a vendor’s inventory claim.

Since its launch, adoption of ads.txt has soared and now 72.5% of the most popular 5,000 websites worldwide selling programmatic ads have adopted ads.txt, according to Pixalate's most recent figures.

As more publishers have adopted ads.txt, advertisers have increasingly restricted their campaigns to only run on websites with verified ads.txt files. According to a Google spokesperson, over 90% of the ad spend that runs through Google’s demand-side platform (DSP) for desktop and mobile web is spent on ads.txt-authorized publishers. (This figure does not include mobile app spend because the IAB Tech Lab is working on how to apply ads.txt to apps.)

Ads.txt just states which vendors have permission to sell a publisher’s inventory. Ads.cert goes a step further by verifying the authenticity of the inventory sold.

“The primary difference is that ads.txt validates sellers, whereas ads.cert validates inventory,” King said.

What’s Next?

The IAB Tech Lab is testing ads.cert but it does not have definitive data pegged for its official release, according to Dennis Buchheim, senior vice president and general manager of IAB Tech Lab.

“It’s possible we will release ads.cert at the same time as the final OpenRTB 3.0 specification, but careful consideration and review is being prioritized over ‘time to market,’” Buchheim said.

The authentication features of ads.cert only work with the OpenRTB 3.0 spec, which is not compatible with previous specs. This means that ads.cert adoption will be dependent on ad tech firms upgrading their infrastructure to use OpenRTB 3.0, which is expected to come out in Q4 2018.