Research conducted by Dr. Sanaz Taheri Boshrooyeh, a PhD graduate of Koç University, Computer Science and Engineering Program, together with Prof. Dr. Alptekin Küpçü and Prof. Dr. Öznur Özkasap has led to the development of a new scalable method designed to protect user privacy on online platforms that rely on invitation-based registration. The system, called “Anonyma”, prevents even system administrators from identifying who invited a particular user to join the platform, addressing a significant privacy concern in such systems. The research and analysis results were published in Journal of Network and Computer Applications, a respected scientific journal in the field of computer networks and applications.
Today, many online platforms and services use invitation systems to control the number of users, prevent fake accounts, or ensure that communities grow in a reliable manner. In such systems, a new user can register on the platform only after receiving a certain number of invitations from existing members. However, platform administrators can usually see who invited whom. According to the researchers, this situation can allow various inferences to be made about users’ social circles, locations, or interests based on invitation links, creating a significant privacy concern.
The Anonyma system addresses this problem in invitation-based platforms. A user can prove that they have received the required number of invitations to join the system through a special mathematical invitation mechanism through cryptographic (encryption-based) methods. However, the identities of the users who issued the invitations remain hidden from both system administrators and other users. This approach preserves the reliability of the invitation mechanism while preventing information about users’ social relationships from being revealed.
The researchers also developed mechanisms to prevent misuse of the system. The design prevents the creation of fake invitations and ensures that the same invitation cannot be used for more than one user. A new user must genuinely receive invitations from a certain number of members before joining the system. This protects the reliability of invitation-based platforms while also guaranteeing user privacy.
The study also places particular emphasis on scalability. In some anonymous invitation systems, computational costs increase rapidly as the number of users grows. In Anonyma, however, the creation and verification of invitations can be performed at a constant cost. This feature makes it possible for the method to be implemented on large online platforms with a substantial number of users.
The researchers propose an extension called AnonymaX that enables anonymous invitation systems to operate across different online platforms. Users on one platform can send invitations to another platform while the identity of the inviter remains hidden. Such systems could contribute to the development of secure identity verification infrastructures across social networks, online communities, and various digital services in the future.