Ephemeral UUID for Protecting User Privacy in Mobile Advertisements

Recently, a universally unique identifier (UUID) for targeting ad services is supported by a smartphone OS, which can be reset and/or halted by a user. However, when a user resets the UUID, all targeted ad libraries are initialized. It means that the user cannot control ad libraries one at a time. As the user interests managed by the same UUID are easily exchanged between the ad service provider and another ad service provider, the user is anxious about the privacy violation. In addition, as the UUID can be tapped on the unencrypted network, the replay attack using the tapped UUID violates the user’s privacy. In this paper, we propose a privacy enhanced UUID that is generated by each ad service provider. As the UUID is encrypted with the time information by each access, the value of

“Enc(Time, UUID)”

is changed frequently. Thus, we call it an ephemeral UUID. The ephemeral UUID is shared through the same ad libraries in any applications, but it cannot be shared through the other ad libraries. Our UUID can be reset by the user and cannot be extracted on the network.