Schedule 31. Chaos Communication Congress

In the wake of the Snowden revelations and the explicit targetting of address book and buddy list information, social service providers may wish to actively avoid learning which of its users are friends. In this talk, we will introduce the workings of a surprising technology called private information retrieval, or PIR. Then, we will describe its use in DP5, a new suite of privacy-preserving presence protocols that allow people to determine when their friends are online (and to establish secure communications with them), without a centralized provider ever learning who is friends with whom.

Presenters:

• Nikita Borisov, University of Illinois at Urbana-Champaign


• George Danezis, University College London


• Ian Goldberg, University of Waterloo [currently on sabbatical at the
  University of Cambridge]

Description:

"We kill people based on metadata."
— General Michael Hayden

People like to know when their social contacts are online. Typically, this is done by a central server keeping track of who is online and offline, as well as of the complete friend graph of users. However, the Snowden revelations have shown that address book and buddy list information is routinely targetted for mass interception. Hence, some social service providers, such as activist organizations, do not want to even possess this information about their users, lest it be taken or compelled from them.

Private information retrieval, or PIR, allows clients to download information from online databases without revealing to the database operators what information is being requested. In this talk, we will introduce the workings of this counterintuitive technology. Then, we will describe its use in DP5, a new suite of privacy-preserving presence protocols that allow people to determine when their friends are online (and to establish secure communications with them), without a centralized provider ever learning who is friends with whom.

Bios:

Nikita Borisov is an Associate Professor of Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign. His research focuses on privacy and anonymity of online communications, as well as protecting the Internet from censorship. With Goldberg, he invented the Off-the-Record Messaging; his research has also influenced the design of the Tor network and the 802.11 security suite.

George Danezis is a Reader in Security and Privacy Engineering at University College London (UK). In the past he has been doing security research at the University of Cambridge, KU Leuven and Microsoft Research. His research focuses on designing and analysing the privacy properties of anonymous communications systems, doing traffic analysis and understanding privacy technologies. He was the co-designer of the Mixminion remailer protocol, and proposed some of the first indirect traffic analysis, and DoS-based attacks against Tor.

Ian Goldberg is an Associate Professor of Computer Science at the University of Waterloo, currently visiting the University of Cambridge. His research focuses on developing usable and useful technologies to help Internet users maintain their security and privacy. Once the Chief Scientist and Head Cypherpunk of Zero-Knowledge Systems, he is currently the chair of the board of directors of the Tor Project, Inc., one of the inventors of Off-the-Record Messaging, and a winner of the Electronic Frontier Foundation's Pioneer Award.

Info

Day: 2014-12-29
Start time: 17:15
Duration: 01:00
Room: Saal 1
Track: Security & Hacking
Language: en

Links:

• iCalendar

Files

• Sildes

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