Anon-Pass: Practical Anonymous Subscriptions.

Area of Science:

• Computer Science
• Cryptography
• Network Security

Background:

• Subscription services often require user identification, compromising privacy.
• Existing anonymity solutions may impose significant performance overheads.
• Balancing service provider efficiency with user anonymity is a key challenge.

Purpose of the Study:

• To design and implement a novel anonymous subscription service.
• To provide strong unlinkability guarantees for user sessions.
• To balance server computation costs with user privacy requirements.

Main Methods:

• Developed a protocol for anonymous user registration and authentication.
• Introduced the concept of 'epochs' for authentication windows.
• Implemented an efficient re-authentication mechanism for users not requiring continuous unlinkability.
• Built and evaluated a research prototype.

Main Results:

• The service provides anonymity, making users indistinguishable beyond random guessing.
• Unlinkability of user sessions across different logins is achieved.
• Short epochs were implemented, balanced by efficient re-authentication.
• Prototype demonstrated minimal client latency and low server memory usage (33 KB/user).

Conclusions:

• The developed anonymous subscription service effectively balances privacy and efficiency.
• The protocol is practical for real-world applications, including music streaming, transit passes, and web proxying.
• The system offers a viable solution for enhancing privacy in subscription-based services.