Embedding Identity in DHT Systems: Security, Reputation and Social Networking Management

1. Embedding Identity in DHT Systems: Security, Reputation and Social Networking Management 2nd EMANICS Workshop on Peer-to-Peer Management Speaker: Luca Maria Aiello SecNet Group Università degli Studi di Torino, Computer Science Department Corso Svizzera, 185 – 10149, Torino, Italy aiello@di.unito.it Embedding identity in DHT systems: security, reputation and social networking management

2. SecNet group members and activities • Research topics: • Peer to Peer • Security on distributed systems • Recommendation systems • Complex network analysis • Social networks • Collaborative tagging systems • … • Giancarlo Ruffo, associate professor • Rossano Schifanella, researcher • Alessandro Basso, researcher • Marco Milanesio, PhD student • Andrè Panisson, PhD student • Luca Maria Aiello, PhD student Embedding identity in DHT systems: security, reputation and social networking management

3. Outline • Motivations • Security issues in structured p2p overlays • Likir, a novel identity based DHT • Reputation management on Likir • ID-based applications developement • Conclusions Embedding identity in DHT systems: security, reputation and social networking management

4. Outline • Motivations • Security issues in structured p2p overlays • Likir, a novel identity based DHT • Reputation management on Likir • ID-based applications developement • Conclusions Embedding identity in DHT systems: security, reputation and social networking management

5. Motivations • Structured P2P systems are mature enough for applications • Scalable, efficient, resistant against random node failures • Still inadequatefor dependableservices • Too many known attacks • Node id and user id aren't coupled • When you are cheated, you have no one to blame! • Design and implementation of a DHT middleware resistant to most known overlay attacks • Preserving: • Scalability • Decentralization • Efficiency Embedding identity in DHT systems: security, reputation and social networking management

6. Motivations Security Identity management Reputation Id-based applications Embedding identity in DHT systems: security, reputation and social networking management

7. Outline • Motivations • Security issues in structured p2p overlays • Likir, a novel identity based DHT • Reputation management on Likir • ID-based applications developement • Conclusions Embedding identity in DHT systems: security, reputation and social networking management

8. Attacker model • A malicious nodeis a participant in the system that does not followthe protocol correctly. It can: • generate packets with arbitrary content • perform IP spoofing • interceptand modifycommunications between other nodes • colludewith other attackers • run and control several nodes Embedding identity in DHT systems: security, reputation and social networking management

9. Attacks against DHTs a. Storage attacks b. Routing attacks c. DDoS attacks d. Sybil attack e. Man In The Middle Embedding identity in DHT systems: security, reputation and social networking management

10. Applying countermeasures • Random NodeIds  Sybil, routing • Few nodes per user  Sybil • Verifiable node identity  Routing, pollution • Secure communication protocol  Routing, MITM • Safe bootstrap  Routing (partitioning) No existent DHT grants these features Embedding identity in DHT systems: security, reputation and social networking management

11. Current DHT designs Chord Pastry Tapestry Viceroy Kademlia CAN Embedding identity in DHT systems: security, reputation and social networking management

12. Outline • Motivations • Security issues in structured p2p overlays • Likir, a novel identity based DHT • Reputation management on Likir • ID-based applications developement • Conclusions Embedding identity in DHT systems: security, reputation and social networking management

13. Likir Layered Id-based Kademlia-like InfRastructure Problem: loose binding between node and identity Solution: a certification service Challenge: preserving the p2p paradigm pureness Embedding identity in DHT systems: security, reputation and social networking management

14. Likir: architectural model • Many other attempts to secure overlay networks: • Myrmic • KadSec • Maelstrom • … • In Likir security problems are solved with: • Registration mechanism • Communication • protocol enhancement Embedding identity in DHT systems: security, reputation and social networking management

15. Likir: subscription Embedding identity in DHT systems: security, reputation and social networking management

16. Likir: node session Embedding identity in DHT systems: security, reputation and social networking management

17. Likir: content store All RPC used are the same defined in Kademlia. We customize only the STORE: • Simple API: • bootstrap() • put(key, obj, type, ttl) • get(key, type, userID, recent) Embedding identity in DHT systems: security, reputation and social networking management

18. Likir: security properties Routing Sybil Storage / DDOS MITM SPoF a. Random generated NodeIds • b. Verifiable identity • No masquerading • Account bound to every node • ID-based applications integration • c. Credentials bound to contents • Verifiable ownership (see later) • d. Secure communication protocol • Resistant to interleaving attacks e. The Certification Service is contacted only ONCE Embedding identity in DHT systems: security, reputation and social networking management

19. Cryptographic primitives does not effectively impact on performance The main overhead is given by the initial nonce exchange Likir: performance analysis GET PUT Embedding identity in DHT systems: security, reputation and social networking management

20. Outline • Motivations • Security issues in structured p2p overlays • Likir, a novel identity based DHT • Reputation management on Likir • ID-based applications developement • Conclusions Embedding identity in DHT systems: security, reputation and social networking management

21. Reputation system • Content credentials allows to know the publisher of any object • A reputation system can be built to punish polluters • Defined at an application level. • RS exhibits a simple APIfor the communication with applications - blacklist(userID) - • Likir does not define a specific RS • different application suites could adopt differentsystems, depending on their needs; • For our experiments we use: • Blacklist + gossip-basedapproach Embedding identity in DHT systems: security, reputation and social networking management

22. Banishment of polluters Snapshot of a simulated massive pollution attack Embedding identity in DHT systems: security, reputation and social networking management

23. Outline • Motivations • Security issues in structured p2p overlays • Likir, a novel identity based DHT • Reputation management on Likir • ID-based applications developement • Conclusions Embedding identity in DHT systems: security, reputation and social networking management

24. Putting things together in applications • In distributed identity-based commercial applications, user data are retained by central servers. • Secure infrastructure • Loss of user privacy • Exploiting DHT systems for data storage could preserveprivacy… • Respect of user data secrecy • Infrastructure prone to common attacks • Likir becomes an ideal decentralized platform for privacy preserving ID-based applications Embedding identity in DHT systems: security, reputation and social networking management

25. Decentralized social network framework • Secure • Applications share the same identity management layer • ID-based information retrieval filtering parameters available • Privacy granted through encryption • OpenID enabled • CS could work also as repository for applications showcase and download • Secure platform Identity Application layer Embedding identity in DHT systems: security, reputation and social networking management

26. Some Likir based applications • LiCha: Fully distributed instant messaging application • User data stored in the DHT • Network bandwith consumption is minimized during content retrieval due to ID-based index side filtering • Personal data are encrypted before being stored • Every content is signed by Likir layer • Fully decentralized tag based search engine • Ongoing work… Embedding identity in DHT systems: security, reputation and social networking management

27. Outline • Motivations • Security issues in structured p2p overlays • Likir, a novel identity based DHT • Reputation management on Likir • ID-based applications developement • Conclusions Embedding identity in DHT systems: security, reputation and social networking management

28. Conclusions • Embedding strong identity into the overlay layer solves many DHT security issues and offers new “beyond file sharing” opportunities for pure p2p paradigm • First DHT design facing a so wide spectrum of attacks (AFAWK) • Scalability and efficiency is preserved • The most common criticism: “Yes, that’s secure, but you introduced a centralized control and trust point! That’s no more p2p!” • CS is involved only once per peer, in a service subscription phase • Yes, we have to trust CS, but we think this is an acceptable compromise • CS solves the first bootstrap problem Embedding identity in DHT systems: security, reputation and social networking management

29. L. M. Aiello, M. Milanesio, G. Ruffo, R. Schifanella   "Tempering Kademlia with a Robust Identity Based System", In the 8th International Conference on Peer-to-Peer Computing 2008 (P2P'08), RWTH Aachen University, Germany, 2008 L. M. Aiello , L. Chisci, R. Fantacci, L. Maccari, M. Milanesio, M. Rosi   "Avoiding eclipse attacks on Kad/Kademlia: an identity based approach.", In ICC 2009 Communication and Information Systems Security Symposium, to appear References To get Likir library, or related publications visit: http://likir.di.unito.it For information, feedback and suggestions, please contact me: aiello@di.unito.it Embedding identity in DHT systems: security, reputation and social networking management

30. Embedding Identity in DHT Systems: Security, Reputation and Social Networking Management 2nd EMANICS Workshop on Peer-to-Peer Management Thank you for your attention! Speaker: Luca Maria Aiello SecNet Group Università degli Studi di Torino, Computer Science Department Corso Svizzera, 185 – 10149, Torino, Italy aiello@di.unito.it Embedding identity in DHT systems: security, reputation and social networking management