Tuesday July 19, 2016 at 06:15 PM by Emin Gün Sirer

The Ethereum hard fork is in a few days. Having looked at the proposed hard fork code, I discuss what I believe is the weakest part of the HF code.

Sunday July 17, 2016 at 12:07 PM by Emin Gün Sirer

Following a hard fork, there will be two chains. In cross-chain replay attacks, one can attack a smart contract by moving transactions from one chain to the other. Post describes a potential attack.

Wednesday July 13, 2016 at 10:45 AM by Emin Gün Sirer

Reentrancy bugs are difficult to catch. This distilled, illustrative example shows how even a diligently-written contract with invariant checks can go wrong.


Our first IC3 retreat in NYC on June 17, 2016 was a great success, with more than 80 attendees from industry and academia. The slides and video from the retreat are now available at the link above

IC3 Researchers discovered flaws in The DAO, the largest crowd-funded smart contract in command of $150M, and called for a moratorium until the smart contract can be updated.


Solidus is a cryptocurrency based on blockchains that can be run by a confederation or consortium of trustworthy entities.

Hawk enables privacy-preserving blockchainds and smart contracts by storing encrypted transactions on the blockchain, and relying on cryptography to retain the security of the cryptocurrency.

Bitcoin-Next Generation is a modification to Bitcoin that enables the system to scale to the limits of the network without being hampered by an artificial blocksize limitation. It does not require any modifications to Bitcoin's trust model.

Town Crier provides authenticated data feeds for smart contracts

  • A postdoc position is available in Cornell/CornellTech and Ethereum Foundation Research Group.