Ads.cert, short for “advertising certificate”, is a digital security protocol used in the online advertising industry to verify the authenticity of ad inventory and prevent fraudulent activities. It works by using cryptographic signatures to validate the identity of each party involved in the ad transaction, including the advertiser, publisher, and ad exchange. This ensures that the ad being served is legitimate and not tampered with, providing a more secure and transparent environment for digital advertising. Ads.cert is a crucial tool in the fight against ad fraud and helps to build trust between advertisers and publishers in the digital advertising ecosystem.