1 / 33

Privacy in Content Oriented Networking: Threats and countermeasures

Privacy in Content Oriented Networking: Threats and countermeasures . Abdelberi Chaabane, Emiliano De Cristofaro , Mohamed Ali Kaafar , and Ersin Uzun. A brief History of networking. 3 Interconnecting information. Telephony. TCP/IP. 2 Interconnecting hosts.

nat
Download Presentation

Privacy in Content Oriented Networking: Threats and countermeasures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Privacy in Content Oriented Networking: Threats and countermeasures Abdelberi Chaabane, Emiliano De Cristofaro, Mohamed Ali Kaafar, and ErsinUzun

  2. A brief History of networking 3 Interconnecting information Telephony TCP/IP 2 Interconnecting hosts 1 Interconnecting wires

  3. Change in Communication Paradigm • Today Internet struggles • Scalability • Mobility • Security • Move to Content-oriented Network • Traffic is already content-oriented • CDN, overlays, P2P • Users/applications care “what to receive” • They don’t care “from whom” • Host based communication model is getting ‘’outdated’’

  4. Notable Content Oriented Networking Architectures DONA NetInf Network of Information

  5. Macro-building blocks • Named Content • Objects are named to facilitate data dissemination and search • Content Based Routing • Routing content rather than host • Content Delivery • Using multipath routing and leveraging in network caching • In Network caching • All components provide caching capability

  6. CCN Operations

  7. Contributions • Systematic study of privacy challenges in CON • Exposing several worrisome issues • Proposing some countermeasures • Highlighting open problems • Comparing CON to Today’s Internet (TI) from a privacy perspective

  8. Outline • Privacy challenges in CON Cache privacy Content Privacy Name privacy Signature privacy • The potential of CON privacy Anonymity Censorship Resistance Untraceability Data authenticity and confidentiality

  9. CON Privacy Name Privacy Cache Privacy • Names are related to the content • Infer what a user is consuming • Data is cached in every hop • Infer who consumed what Signature Privacy Content Privacy • Content is signed • Identify the communicating parties • Encryption is not mandatory • Publicly available content spied on / censored

  10. Timing attack RTTS RTTC Fetch the targeted contentRTTt • If |RTTt -RTTc| < ε: Content has been fetched by a neighboring consumer • If RTTt > RTTc and RTTt < RTTs: Content has been recently fetched from the source • Otherwise: The target content has not been consumed

  11. Potential Solution • Wait before reply • When a content m is fetched, the corresponding RTTm is stored • All subsequent requests to m are delayed with RTTm Increased the delay It provably achieves perfect privacy[1] No assumption about content correlation/ Network topology Reduced bandwidth 1: Acs, G., Conti, M., Gasti, P., Ghali, C., & Tsudik, G. Cache Privacy in Named-Data Networking. ICDCS’13.

  12. Potential Solution • Delay the first K • When a content m is fetched, the corresponding RTTm is stored and a random number K is chosen • K subsequent requests to m are delayed with RTTm Assumption about content correlation Increased delay for non popular content Popular content is not delayed Formal model to quantify the tradeoff privacy/latency [1] Reduced bandwidth

  13. Potential Solution • Collaborative caching • Multiple caches collaborate to create a distributed cache

  14. Potential Solution • Collaborative caching • Multiple caches collaborate to create a distributed cache Administrative collaboration Potential Delay Increases the anonymity set Increases hit rate

  15. Content Based Monitoring and Censorship • CON routers • Long-term storage • Computationally powerful • ‘Less’ powerful adversary is needed to perform censorship

  16. Potential Solution • Broadcast encryption • The producer send an encrypted message to a set of users N • Only users in N can decrypt the message Producer generate/store N keys Producer public key and cipher text are of size of O(√N) Content is encrypted once Caching is preserved Fine grained user control (revocation)

  17. Potential Solution • Proxy re-encryption

  18. Potential Solution • Proxy re-encryption Asymmetric encryption Content is available for any user Content is encrypted once Caching is preserved Fine grained user control (revocation)

  19. Monitoring/Tracking • Content name are semantically correlated with the content • E.g. /US/WebMD/AIDS/Symptoms/html • Unlike HTTPS, content name is not encrypted as they are used for routing

  20. Potential Solution • Bloom Filter • Using Bloom filter to obfuscate the content name: • A hierarchical Bloom filter for routing table • A counting Bloom filter for each forwarding interface Introduce false positives BF require periodic resetting Obfuscates content name Small architectural changes Reduce the size of routing/forwarding tables

  21. Censorship/ Monitoring • Signature is used to provide guarantee on provenance and integrity • This signature can be used to censor/monitor the content.

  22. Potential Solution • Group Signature • Group Signature

  23. Potential Solution • Group Signature • Hide the signer in a set of potential signers (signer ambiguity) Pub Key Priv Key Group Manager

  24. Potential Solution • Group Signature • Hide the signer in a set of potential signers (signer ambiguity) Presence of a group manager Censorship possible Signature still verifiable Efficient

  25. Potential Solution • Ring Signature • Hide the signer in a set of potential signers (signer ambiguity) • Signature is generated from the signer private key and a set of public key Pub Key Priv Key

  26. Potential Solution • Ring Signature • Hide the signer in a set of potential signers (signer ambiguity) • Signature is generated from the signer private key and a set of public key Communication overhead linear in the size of the ring Censorship possible Signer anonymity protected Trustful content (as long as all signers are trustworthy) No signers interaction / No group manager

  27. Outline • Privacy challenges in CON • Cache privacy • Content Privacy • Name privacy • Signature privacy • The potential of CON privacy • Anonymity • Censorship Resistance • Untraceability • Data authenticity and confidentiality

  28. Anonymity Internet CON A Trusted Anonymzing proxy Natively provided by the architecture (no SRC/DST) - A single point of failure - A Local adversary could monitor all the traffic Mix Networks: ANDaNA[2] • 2 Hops to the source • Low latency • Partially disable CON caching • CCNx specific Mix Networks e.g. Tor • 3 Hops to the source • Low latency [2] ANDaNA: Anonymousnamed data networking application.DiBenedetto, S., Gasti, P., Tsudik, G., & Uzun, E. NDSS'12

  29. Censorship Internet CON DNS Tempering Effective in some CON Content (name) blacklisting Host blacklisting Easier in CON: • Name/Content are not encrypted • No need for specialized hardware DPI (Content blacklisting) • Strong adversary • specialized Hardware At a single router, censorship appears to be easier in CON

  30. Tracking Internet CON Cookies • Widespread • Efficient • Tailored to the business model • No same origin policy • Only dynamic content can be tracked • Business model migration ? Stateless Tracking -More difficult to carry (no addresses + caching) • How to handle security incident ? • Using IP and host fingerprinting CON is more resilient to tracking but poses new challenges

  31. Data authenticity and confidentiality Internet CON One size fits all (SSL) • Well studied • Highly optimized End to End trust model • Different consumer = different trust model • Widely accepted (PKI) or new trust management model

  32. Take home messages • Content Oriented Networking Privacy More resilient to tracking ‘’Weak’’ anonymity as native feature Possibly more vulnerable to censorship Some privacy challenges due to caches, naming, signatures

More Related