Re: Non-source routing (was "failures during the preparation phase")

Do landmark nodes have a special role in the network? Must someone
"appoint" a landmark node, or can any node step in and fill this role at
any time? Where is the "Universe Creator" located? Am I correct in
inferring that this is a system designed to be run on a centralized node
that knows about the entire network topology?

-Jehan

On Fri, Mar 25, 2016 at 2:36 PM, Daniel Bateman <7daniel77@gmail.com> wrote:

> Interesting!
>
> Can Interledger function with a system like PrivPay?
> On Mar 25, 2016 2:32 PM, "Pedro Moreno Sanchez" <pmorenos@purdue.edu>
> wrote:
>
>> Hello,
>>
>> my name is Pedro Moreno-Sanchez and I am a PhD student at the computer
>> science department at Purdue. My current research focuses on security and
>> privacy issues on credit networks. Moreover, I will be doing an internship
>> at Ripple this summer. Thus, I hope I can use this opportunity to meet some
>> of you there and discuss the interesting things that are going on in this
>> group.
>>
>> I would like to bring to your attention a (non-source) routing approach
>> called landmark routing [1]. In a nutshell, this approach calculates a path
>> between a sender and a receiver through an intermediary node called
>> landmark. The idea behind this approach is to calculate the shortest path
>> (i.e., Breadth-First Search) from the landmark to every other node and vice
>> versa, from every node to the landmark. Then, a payment path from sender to
>> receiver can be reconstructed as sender -->other nodes --> landmark -->
>> other nodes ---> receiver. Vismanath et al.[2] have shown that landmark
>> routing performs much faster than other routing approaches (e.g., using
>> max-flow) in credit networks.
>>
>> Given the similarities between a credit network and the ILP settings, it
>> might be worth it discussing this approach here. Moreover, as part of my
>> research, I have studied whether it is possible to use landmark routing to
>> build a credit network with privacy preserving payments. This is
>> challenging not only because of possible privacy leaks while calculating
>> payment paths but also due to privacy leaks during the calculation of the
>> available credit in a path.
>>
>> To overcome these challenges, we designed a system called PrivPay [3], a
>> credit network system that uses a privacy-enhanced version of landmark
>> routing to perform privacy preserving payments. More recently, we have
>> designed a privacy-preserving credit network system with which we show that
>> it is possible to enforce strong privacy guarantees as we did with PrivPay
>> but in a distributed setting, where each node in the network only knows its
>> neighbors (e.g., its own credit links). Although this last work is not
>> published yet, I would be glad to share and discuss it with you if you are
>> interested.
>>
>> I would be interested on discussing my experiences during my research
>> regarding not only routing mechanisms on credit networks, but also privacy
>> preserving payments. I believe that privacy is an interesting and important
>> aspect that might be worth considering on the ongoing discussions about ILP.
>>
>> --
>> [1] P. F. Tsuchiya, “The Landmark Hierarchy: A New Hierarchy for Routing
>> in Very Large Networks,” SIGCOMM Comput. Commun. Rev., vol. 18, no. 4,
>> pp. 35–42, Aug. 1988.
>> [2] B. Viswanath, M. Mondal, K. P. Gummadi, A. Mislove, and A. Post,
>> “Canal: Scaling Social Network-based Sybil Tolerance Schemes,” in EuroSys
>> ’12, 2012, pp. 309–322.
>> [3] Moreno-Sanchez, P., Kate, A., Maffei, M., and Pecina, K. Privacy
>> preserving payments in credit networks: Enabling trust with privacy in
>> online marketplaces. In NDSS(2015).
>> http://www.internetsociety.org/doc/privacy-preserving-payments-credit-networks-enabling-trust-privacy-online-marketplaces
>>
>