Everything You Need to Know About Ads.cert

Reading time: 6 minutes

Programmatic ad selling has made a lot of advancements over the past few years. However, there are still plenty of challenges that the entire ad tech industry faces. 

The greatest challenge? Transparency and security throughout the digital ad supply chain.

In an attempt to accomplish transparency and security, ads.txt became the driving force among all programmatic players. Unfortunately, ad.txt. Isn’t exactly a bullet-proof solution against ad fraud — especially when you have human errors such as the misspelling of a demand partner or supply partner’s name within the ads.txt file. 

The Interactive Advertising Bureau’s (IAB) newest solution to making the digital ad supply chain a better place is ads.cert. But what is ad.cert and can it really live up to the hype of helping publishers and advertisers minimize instances of ad fraud?

Let’s discuss. 

What Exactly Is Ads.cert and How Is it Different From Ads.txt?

Simply put, ads.cert is the upgraded version of ads.txt, given to us by the IAB. It uses cryptographically signed bid requests to authenticate inventory. It also allows buyers to track that inventory’s path throughout the digital supply chain to ensure buyers that they’re only purchasing the intended inventory from authorized publishers.

You’re probably wondering how this is any different from ads.txt. The “ads” in ads.text actually stands for authorized digital sellers, and it was IAB’s initial standard for combating ad fraud. Essentially, ads.txt verifies that a business is actually authorized to sell a publisher’s inventory, which puts the publisher in control over the ad inventory pipeline to an extent.

It’s also to ensure that the buyers are only buying from authorized sellers — particularly, to combat the common ad fraud method known as domain spoofing.

While ads.cert does the same thing ads.txt does, it kicks things up a notch by validating the information passed along between the buyer and seller at each stage of the digital ad supply chain. The goal is to ensure that information isn’t vulnerable to modification or gaming, so it acts like a digital signature that helps buyer’s verify a specific website’s inventory to prevent fraudsters from getting in the middle and making a mess.

Why Does Ads.cert Matter?

The reason why ads.cert is so important is because it allows advertisers to validate publishers and whether or not they’re authorized to sell inventories to begin with. When we talk about the shortcomings of ads.txt (hence the need for ads.certs) we’re talking about the challenges that have cropped up despite the script providing a way to authenticate both parties.

Those challenges would include the following:

  • DSPS and media buyers often ignored quality ad inventories simply because of a misspelled word or name in the ads.txt file.
  • Unknown third parties were often asked to add a seller’s ads.txt files which didn’t look good in front of media buyers.
  • Ads.txt never had the capability of specifying inventory type. This often led to selling repackaged inventories — multiple times. For example, display ad inventory could essentially be sold as video inventory and garner higher CPMS under false pretenses.

With ads.cert, the goal is to validate the digital ad supply chain every step of the way. This mostly guarantees that cyber criminals aren’t able to get their hands on your inventory and manipulate it in any way. 

The type of data that an advertiser can get from an ads.cert file include:

  • The ad type, i.e., video ad slot, banner ad slot, etc
  • The IP address, which can be cross-referenced with any blocklists available
  • The user’s device type — tablet, desktop, laptop, smart phone, etc
  • The user’s browser type, such as Safari, Firefox, Chrome, and so on
  • The user’s geographical location
  • The position of the ad on the webpage, as in above the fold, below the fold, inline, and even whether or not it’s a sticky ad slot
  • The doman

In addition to the information above, sellers can also add their own signature to take the transparency even further and prove their trustworthiness. 

Ultimately, ads.cert is necessary because it ensures brand safety while increasing eCPM for your ad inventory. It also gives ad tech players the advantage of blacklisting ad fraudsters while preventing the following:

  • Unfair or fraudulent competition
  • IP and domain fraud
  • Device ID fraud

How Does Ads.cert Work?

Let’s take a quick look at exactly how ads.vert works:

  • First, the publisher will generate two keys. These keys are known as a “public key” and a “private key.” The public key remains secure but also accessible by the demand side partners (DSPs) and media buyers that validate the bid requests against their signatures. Private keys, however, are both secure and accessible for buying partners that generate and sign the bid requests (such as the supply-side partners — SSPs).
  • Next, the SSPs will attach an encrypted signature to the bid request. From there, they’ll send it along to their DSPs along with the details mentioned earlier for their available impression. (the domain, publisher’s niche, user’s location, etc.)
  • Once the DSPs receive the bid request, they must generate another signature for that same bid request. From there, the DSPs can compare their signature with the one sent by the SSPs to verify the legitimacy of the bid request in question.
  • If any alterations occur within the generated signatures, the DSPs will be able to identify it and can opt to reject the bid response if they feel it’s untrustworthy.

This all happens within milliseconds of the programmatic ad bidding process. 

The entire verification process is just one more step towards achieving full transparency in programmatic ad buying and selling. It allows advertisers to know for sure the type of ad inventory they’re buying, and that they’re not buying display inventory that has been repackaged as video ads or vice versa.

It’s essentially what all the players in the ad tech industry are calling for — except fraudsters and shady vendors, of course. 

Why Hasn’t Ads.cert Been Adopted Yet?

While all of this ads.cert verification stuff sounds great, it isn’t currently in use. The IAB actually launched ads.cert back in 2019, hoping it would be the ultimate solution or at least the best next step in the right direction. 

However, the solution has been sidelined (for now). This is mostly because the ads.cert file can only be implemented right now by upgrading your tech infrastructure to OpenRTB 3.0 as it can’t run on OpenRTB 2.5 or any older versions. 

So, what’s the issue? — Why not just upgrade?

Well, unfortunately, OpenRTB 3.0 is not what the ad tech players refer to as “backward compatible.” In other words, you won’t be able to use it with any existing legacy technology systems. All the ad tech players — demand-side platforms, supply-side platforms, ad exchanges, and ad networks would have to be willing to shell out a lot of money to hire the engineers that can either make existing systems compatible. Or successfully upgrade  the infrastructure to Open RTB 3.0.

Of course, this doesn’t mean the concept of ads.cert is going anywhere. It’s only a matter of time before ad tech players are forced to upgrade and roll out their networks utilizing Open RTB 3.0. In the meantime, advertisers and publishers are stuck with ads.txt and finding other ways to be transparent.

Looking to the Future

Ad fraud has been a huge issue within the ad tech industry, and both advertisers and publishers alike are tired of losing out on ad spend and CPMs because of it. Not only does ad fraud negatively impact your bottom line, but it genuinely messes with advertiser’s and their brand as their customer bases begin to view them as scam artists rather than true business owners.

It’s why all ad tech players are putting their heads down and trying to come up with better ways to fight it.

However, ads.txt has allowed publishers to move forward within the industry while maintaining a certain level of transparency. Ads.cert is the next step for that transparency, but it’s going to take some time to see just how effective it will be once adopted and how many publishers will follow suit. 


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