Hamid Mozaffari (University of Massachusetts Amherst), Amir Houmansadr (University of Massachusetts Amherst)

Private information retrieval (PIR) enables clients to query and retrieve data from untrusted servers without the untrusted servers learning which data was retrieved.

In this paper, we present a new class of multi-server PIR protocols, which we call emph{heterogeneous PIR (HPIR)}. In such multi-server PIR protocols, the computation and communication overheads imposed on the PIR servers are non-uniform, i.e., some servers handle higher computation/communication burdens than the others. This enables heterogeneous PIR protocols to be suitable for a range of new PIR applications.

What enables us to enforce such heterogeneity is a unique PIR-tailored secret sharing algorithm that we leverage in building our PIR protocol.

We have implemented our HPIR protocol and evaluated its performance in comparison with regular PIR protocols. Our evaluations demonstrate that a querying client can trade off the computation and communication loads of the (heterogeneous) PIR servers by adjusting some parameters. For example in a two server scenario with a heterogeneity degree of $4/1$, to retrieve a $456$KB file from a $0.2$GB database, the rich (i.e., resourceful) PIR server will do $1.1$ seconds worth of computation compared to $0.3$ seconds by the poor (resource-constrained) PIR server; this is while each of the servers would do the same $1$ seconds of computation in a homogeneous settings. Also, for this given example, our HPIR protocol will impose $912$KB communication bandwidth on the rich server compared to $228$KB on the poor server (by contrast to $456$KB overhead on each of the servers for a traditional homogeneous design).

View More Papers

A View from the Cockpit: Exploring Pilot Reactions to...

Matthew Smith (University of Oxford), Martin Strohmeier (University of Oxford), Jonathan Harman (Vrije Universiteit Amsterdam), Vincent Lenders (armasuisse Science and Technology), Ivan Martinovic (University of Oxford)

Read More

Measuring the Deployment of Network Censorship Filters at Global...

Ram Sundara Raman (University of Michigan), Adrian Stoll (University of Michigan), Jakub Dalek (Citizen Lab, University of Toronto), Reethika Ramesh (University of Michigan), Will Scott (Independent), Roya Ensafi (University of Michigan)

Read More

Detecting Probe-resistant Proxies

Sergey Frolov (University of Colorado Boulder), Jack Wampler (University of Colorado Boulder), Eric Wustrow (University of Colorado Boulder)

Read More

Compliance Cautions: Investigating Security Issues Associated with U.S. Digital-Security...

Rock Stevens (University of Maryland), Josiah Dykstra (Independent Security Researcher), Wendy Knox Everette (Leviathan Security Group), James Chapman (Independent Security Researcher), Garrett Bladow (Dragos), Alexander Farmer (Independent Security Researcher), Kevin Halliday (University of Maryland), Michelle L. Mazurek (University of Maryland)

Read More