Cross-Platform End-to-End Encryption of Contact Data for Mobile Platforms using the Example of Android

Storing and synchronizing personalized or businessrelated data, especially contact data, is increasingly done by cloud services. Thereby, control over personal data is subject to the technical conditions and measures of the cloud service providers. However, abstaining from the utilization of cloud services is not an alternative as their amenities are indispensable both for private and business users. End-to-end encryption, as it is already maturely applied for various communication services, would enable users to still keep their contacts on remote storage nodes, but save them in encrypted form. Although, the principal concepts for this kind of security measure are well-studied, there is still no service for protecting cloud-based contact data by end-to-end encryption using mobile platforms. This paper presents the ideas and the architecture for end-to-end encryption of contact data using the example of Android.