This paper presents Musubi, a mobile social application platform that enables users to share any data type in real-time feeds created by any application on the phone. Musubi is unique in providing a disintermediated service to end users; all communication is supported using public key encryption thus leaking no user information to a third party. Despite the heavy use of cryptography to provide user authentication and access control, users found Musubi simple to use. We embed key exchange within familiar friending actions, and allow users to interact with any friend in their address books without requiring them to join a common network a priori. Our feed abstraction allows users to easily exercise access control. All data reside on the phone, granting users the freedom to apply applications of their choice.

Software products released into the field typically have some number of residual defects that either were not detected or could not have been detected during testing. This may be the result of flaws in the test cases themselves, incorrect assumptions made during the creation of test cases, or the infeasibility of testing the sheer number of possible configurations for a complex system; these defects may also be due to application states that were not considered during lab testing, or corrupted states that could arise due to a security violation. One approach to this problem is to continue to test these applications even after deployment, in hopes of finding any remaining flaws. In this paper, we present a testing methodology we call in vivo testing, in which tests are continuously executed in the deployment environment. We also describe a type of test we call in vivo tests that are specifically designed for use with such an approach: these tests execute within the current state of the program (rather than by creating a clean slate) without affecting or altering that state from the perspective of the end-user. We discuss the approach and the prototype testing framework for Java applications called Invite. We also provide the results of case studies that demonstrate Invite's effectiveness and efficiency.