Our next Crypto Day will be May 6th at Georgetown.We will hold in it in room 155 of the business school building; see here for directions.Please find the abstract of the talks below.The plan is to allocate 1 hour 20 minutes for each talk, with the talk itself to an hour, and then there can be 20 minutes (hopefully lively) questions/discussion.In terms of getting to Georgetown, check out the GUTS bus.Otherwise, the closest metro stop is probably Foggy Bottom.Preliminary schedule: 3:20- George Non-Malleable Codes for Bounded Depth, Bounded Fan-in Circuits Non-malleable codes are a relaxation of error correcting codes, for settings in which privacy, but not necessarily correctness, is desired.Instead of requiring that after modification—i.e.tampering—of the codeword, the original message can always be recovered, non-malleable codes allow a different message to be recovered, as long as the recovered message is unrelated to the original message.This relaxation potentially allows for the construction of coding schemes for rich classes of tampering classes, beyond what can be done for error correcting codes.

In applications, non-malleable codes are used to encode the memory of a device, and thus protect against (certain classes) of adversarial tampering.Lower-Bounds on Assumptions behind Indistinguishability Obfuscation Mohammad Mahmoody In this talk, we first show that basing IO on a variety of assumptions (e.g., trapdoor permutations, bi-linear maps, etc) in a weakly black-box way is as hard as basing public-key encryption on one-way functions (in a non-black-box way).bitcoin xbox miningThe latter has remained as one of the most challenging open questions in cryptography.debian bitcoin makeThen, by combining our results with a recent result of Brakerski, Brzuska, and Fleischhacker, we rule out any fully black-box construction of IO from the same set of primitives assuming the existence of one-way functions and that the polynomial-hierarchy does not collapse.zinsen auf bitcoin

New Inference Attacks on Order-Preserving and Order-Revealing Encryption Paul Grubbs Accessing Data while Preserving Privacy Georgios Kellaris We present a new model of differentially private storage where differential privacy is preserved even against an attacker that controls the data and the queries made to it.bitcoin breakupWe give a generic construction of differentially private storage that combines ORAM and differentially private sanitizers.bitcoin current value in inrWe also provide efficient constructions and lower bounds for some specific query sets.ethereum chrome pluginWe have implemented some of our algorithms, and report on their efficiency.Joint work with Georgios Kellaris, George Kollios, Kobbi Nissim, and Adam O’Neill.bitcoin 2pm

Bio: Georgios is currently a Post-Doctoral Fellow at CRCS, Harvard University, and at Boston University.He received his Ph.D.degree in Computer Science and Engineering from the Hong Kong University of Science and Technology (2015), under the supervision of prof. Dimitris Papadias, and with the support of the Hong Kong Ph.D.peter joseph bitcoinHe holds a 4-year B.Sc.50 miner litecoinin Informatics and Telecommunications from the University of Athens (2006) and a 2-year M.Sc.degree in Digital Systems from the University of Piraeus (2008).He has worked as a researcher at the University of Piraeus in Greece, the Singapore Management University and the Nanyang Technological University in Singapore, and at Boston University.His research interests include databases and differential privacy.DC CRYPTO DAY FRIDAY, OCTOBER 30 JOHNS HOPKINS UNIVERSITY (HOMEWOOD CAMPUS) ∙ BALTIMORE, MD Be sure to join us for the next DC area Crypto Day scheduled from 10:00 a.m.

on Friday, October 30 at the Homewood Campus of Johns Hopkins University.The theme of this installment is Bitcoin.Parking Location: South Garage 3100 Wyman Park Drive Baltimore, MD 21211 Location of Talks: Sherwood Room, Levering Hall – Google Maps Link – Campus map.*Please note that Levering Hall is building number 40 on the map and South Garage Parking is the one next to building 45 on the map.Agenda: 10:00 AM – 11:00 AM |David Evans, University of Virginia 11:10 AM – 12:10 PM |Andrew Miller, University of Maryland 12:10 PM – 1:40 PM | Lunch 1:40 PM – 2:40 PM |Ranjit Kumaresan, Massachusetts Institute of Technology 2:50 PM – 3:50 PM |Matthew Green, Johns Hopkins University 4:00 PM – 5:00 PM | Panel discussion Note that there is a 10:00 minute break between the talks.Please find the titles and abstracts below.Speaker: David Evans, University of Virginia Title: Trick or Treat?: Bitcoin for Non-Believers, Cryptocurrencies for Cypherpunks Abstract: This (non-research) talk will start with a tutorial introduction to cryptocurrencies and how bitcoin works (and doesn’t work) today.

We’ll touch on some of the legal, policy, and business aspects of bitcoin and discuss some potential research opportunities in cryptocurrencies.Speaker: Andrew Miller, University of Maryland Title: Privacy-preserving Smart Contracts /2015/675.pdf Abstract: Existing blockchain-based cryptocurrencies such as Bitcoin and Ethereum, store all financial transactions in the clear on the blockchain.This compromises the privacy of financial transactions, which is essential in numerous applications.Hawk is a blockchain-based smart contract system that stores encrypted transactions on the blockchain, and relies on cryptography to retain the security of the cryptocurrency.A Hawk programmer can write a private smart contract in an intuitive manner without having to implement cryptography, and our compiler automatically generates an efficient cryptographic protocol where contractual parties interact with the blockchain, using cryptographic primitives such as succinct zero-knowledge proofs.

To formally define and reason about the security of our protocols, we also formalize a new simulation-based “blockchain model” of secure computation, which is of independent interest.Speaker: Ranjit Kumaresan, Massachusetts Institute of Technology Title: How to Use Bitcoin to Design Fair Protocols Abstract: I will talk about a recent line of work that integrates traditional secure computation with a formal financial framework.This line of work identifies and abstracts some key transaction functionalities offered by the Bitcoin network, and shows how to incentivize correct behavior in secure computation (and other cryptographic tasks) in a model where parties have access to such a transaction functionality.Speaker: Matt Green,  Johns Hopkins University Title: TBD Abstract: TBD *Please note that lunch will not be provided, click on Crypto Conference Dining Options to check out local nearby options.Please RSVP to Sr.Academic Program Coordinator Jessica Finkelstein at jkastne2@jhu.edu by Friday, October 23.