I broke AppLovin's mediation cipher protocol

A security researcher decrypted AppLovin's ad-mediation traffic and found that despite Apple's App Tracking Transparency (ATT) privacy feature, the encrypted requests contain enough device fingerprinting data (hardware model, RAM, screen dimensions, boot time, etc.) to uniquely identify iPhones across different apps and publishers. This fingerprint data, along with tokens for approximately 12 downstream ad networks, is transmitted every ~30 seconds to AppLovin and its partners, making device fingerprinting an effective workaround to ATT's identifier restrictions.