IC3: Advancing the science and applications of blockchains

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by Tiancheng Xie, Jiaheng Zhang, Yupeng Zhang, Charalampos Papamanthou, and Dawn Song on February 12, 2020 at 10:00 AM
Libra is a zero-knowledge proof protocol that achieves extremely fast prover time and succinct proof size and verification time. Not only does it have good complexity in terms of asymptotics, but also its actual running time is well within the bounds of enabling realistic applications. It can be applied in areas such as blockchain technology and privacy-preserving smart contracts. It is currently being implemented by Oasis Labs. This blog post is based on a paper authored by Tiancheng Xie, Jiaheng Zhang, Yupeng Zhang, Charalampos Papamanthou and Dawn Song.
by Michael Mirkin, Yan Ji, Jonathan Pang, Ariah Klages-Mundt, Ittay Eyal, and Ari Juels on December 17, 2019
We have discovered a denial-of-service attack on Bitcoin-like blockchains that is much cheaper than previously described attacks. Such blockchains rely on incentives to provide security. We show how an attacker can disrupt those incentives to cause rational miners to stop mining.
by Itay Tsabary, Alexander Spiegelman, and Ittay Eyal on December 04, 2019
Proof-of-work (PoW) mechanisms secure about 80% of the $250B cryptocurrency market. PoW requires system participants to expend computational resources, and protects the system from attackers who cannot expend resources at an equivalent rate. These systems operate in the permissionless setting and compensate their users with cryptocurrency, having a monetary value. As cryptocurrency prices sore so do the invested resources, and Bitcoin expenditures alone are 0.24% of the global electricity consumption. Arguably, this is superfluous, and lowering the ecological footprint justifies settling for a lower attack threshold.
by Yujin Kwon, Jian Liu, Minjeong Kim, Dawn Song, and Yongdae Kim on September 30, 2019
Decentralization is an essential factor the should be inherently considered in the design of blockchain systems. Even though people design systems for good decentralization, in practice, we often observe that blockchain systems are highly centralized. Bitcoin and Ethereum, as representative examples, are already well known to be highly centralized in terms of network and mining. In fact, poor decentralization appears not only in PoW-based coins but also in coins adopting other mechanisms such as proof-of-stake (PoS) and delegated proof-of-stake (DPoS).
by Bryan Ford and Rainer Böhme on September 23, 2019
If you think you have designed a permissionless decentralized system that is cleverly secured based on rationality assumptions, you haven't. This blog post, based partly on ideas from Rainer Böhme's talk at the recent BDLT Summer School in Vienna, sketches an argument that rationality assumptions are self-defeating in open permissionless systems with weak identities.
by Fan Zhang, Steven Goldfeder, and Ari Juels on September 03, 2019 at 02:00 PM
An oracle is a service that provides data to smart contracts or other systems. Oracles obtain their data from trusted websites. But even those that relay data correctly cannot safely access users' web-session data, because they can't enforce privacy. DECO is a privacy-preserving oracle protocol. Using cryptographic techniques, it lets users prove facts about their web (TLS) sessions to oracles while hiding privacy-sensitive data. DECO can make private and public web data accessible to a rich spectrum of applications, for blockchains and traditional (non-blockchain) systems.
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Wednesday March 18, 2020
Due to concerns for the health of our community, this event is being postponed. Please check back for updates and rescheduling.
Tuesday February 18, 2020
Join us for networking and blockchain research presentations by Dr. Dawn Song from UC Berkeley and IC3, and Dr. Sam Blackshear from Calibra.
Friday November 22, 2019
IC3 faculty, students, sponsors, and guests gather at IC3 Retreats to discuss the major technical challenges, issues and innovatve solutions to widespread blockchain adoption.
Thursday November 21, 2019
Cryptocurrencies do not scale. In this technical deep-dive, we provide an overview of an alternative scaling approach, off-chain protocols, that lets parties transact locally amongst themselves instead of the global network. Off-chain is remarkable as in the best case it lets parties bypass all network fees and blockchain latency, and in the worst-case, the parent blockchainsafeguards the funds of all honest parties. We'll cover the two leading approaches, channel-based networks (lightning et al) and commit-chains (plasma & rollup et al) alongside the new the always online assumption and how the community is trying to alleviate it. If we, as a community, can pull off the implementation of off-chain protocols, it will hopefully unleash a truly permissionless, global and internet-scale financial system.
Thursday October 24, 2019
Tyler Kell is a Research Engineer at Cornell Tech & the Initiative for Cryptocurrencies and Contracts (IC3) in New York City. In a prior life, before becoming a researcher, he worked as a penetration tester and security consultant.
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Featured Projects

AIRS: Automated Incentives for Reforestation Stewardship

The accelerating effect of global climate change is a major challenge for humanity. One critical component of any comprehensive solution is reforestation. As large and effective carbon sinks, forests are important to both conserve and expand. Our project aims to build infrastructure through blockchain for a performance-based incentive to encourage reforestation in developing countries. For further details, please check out the Projects Page.

Carbon Sequestration
Smart Contract

More projects:

  • Libra: A Zero-knowledge Proof System
  • HoneyBadgerBFT: A Practical Asynchronous BFT Protocol
  • Charlotte: Framework for Building Parallel, Interoperable Blockchain Systems
  • VyperFlow: A New Programming Language for Smart Contracts
  • Selfish Mining Re-examined: Revisiting the Selfish Mining Strategy
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