Hardened Dildo.io: A Cryptographically Secure, Usable Matchmaking Service

The website Dildo.io [1] has been used by many MIT students over the last few months as a matchmaking service restricted to students at MIT. However, such a service may have a key security flaw: all the information is centralized, and some central server(s) have access to everyone’s preferences. We wanted to set up a cryptographically secure matchmaking service in which no central server has access to anyone’s preferences, and we wanted to make it difficult for any client or the central server to learn about preferences. In addition, many solutions to secure matchmaking involve incredibly complex protocols, so we set out to make our system as easy to use as possible. 1 Motivation In the 21 century, online matchmaking services have become extremely popular in America. From Tinder to Match.com to OkCupid, dozens of services have popped up. However, in each of these services, a centrally controlled server stores information about the matches of its users. Data breaches, like the one that hit AshleyMadison in mid 2015[9], can reveal everyone’s private match and preference information to external parties. Thus, there is certainly place in the world for cryptographically secure matchmaking. The fundamental motivation for our project was to create a system in which no central server has access to information about individuals’ preferences. We modeled our service after Dildo.io (shown in Figure 1), a popular service started by an East Campus resident in 2016. It is an intra-MIT matchmaking service; in particular, it restricts the set of users to all undergraduate students at MIT and has approximately one thousand users [5]. To mimic this sort of user base, we constructed our system to heavily use MIT’s Athena, and Athena’s Shared File System known as AFS; because all users who have accounts on Athena can access certain shared resources through AFS, we used this as a base in order to ensure that public keys were accessible and data storage was persistent. Fundamentally, our goals for inter-user security are as follows: