Android

On Android, the Protected Audience API operates with a focus on enhanced security and privacy. Relevant signals and data, such as custom audience information, are stored on the user's device. The auction itself is conducted within a Trusted Execution Environment (TEE). This allows for secure and isolated processing of auction logic and data: 

• On-device storage: Data related to user interests and custom audiences is stored directly on the user's Android device.
• TEE-based auctions: When an ad auction is triggered, the process takes place within the TEE, a secure and isolated environment. This ensures that sensitive data remains protected during the auction.

The separation of data storage and auction execution allows for effective re-marketing while adhering to stringent privacy standards.