Blogs

by Emin Gün Sirer and Phil Daian on Monday June 19, 2017 at 10:18 AM
Bancor just raised $144M through the biggest ICO in history. We describe why their approach is flawed.
by Yan Ji, Ari Juels, and Fan Zhang on May 15, 2017 at 10:01 AM
Town Crier is an oracle service for smart contracts.
by Maria Apostolaki, Aviv Zohar, and Laurent Vanbever on Monday May 01, 2017 at 10:48 AM
Cryptocurrencies are vulnerable to attacks targeting the network routing layer. In this guest post, Apostolaki, Zohar and Vanbever show that BGP attacks are back, and this time, they have a high value target.
by Emin Gün Sirer on April 05, 2017 at 08:48 PM
My quick reaction to the latest salvo of shots fired in the war between Core developers and miners.
by Emin Gün Sirer on February 27, 2017 at 10:33 AM
BitFury has been mining smallest-transactions-first. We argue why this is bad for Bitcoin.
by Phil Daian and Ari Juels on February 23, 2017 at 12:23 PM
Blockchains are beginning to turn green. This post describes some of the IC3 research in this direction.
by Adem Efe Gencer and Emin Gün Sirer on February 15, 2017 at 10:18 AM
We characterize the state of the Bitcoin network as of this year, and discover that it has improved by 70% in terms of bandwidth compared to last year alone.
by Adem Efe Gencer and Emin Gün Sirer on February 10, 2017 at 10:10 AM
Miniature world is an evaluation platform which provides a principled way of evaluating different blockchain proposals.
by Jim Ballingall on January 09, 2017 at 08:42 AM
As regulators take a closer interest in cryptocurrencies, IC3 faculty weigh in on if and how they should be regulated.
by Joshua Lind, Ittay Eyal, Peter Pietzuch, and Emin Gün Sirer on December 22, 2016 at 09:10 AM
We unveil a new technology for secure, high throughput, low latency Bitcoin transactions using secure hardware, on the current Bitcoin network.
by Adem Efe Gencer and Emin Gün Sirer on December 06, 2016 at 02:35 PM
We introduce the first workable sharding solution for blockchains.
by Philipp Jovanovic on August 04, 2016 at 12:57 PM
We introduce a novel consensus mechanism that greatly improves security, throughput, and transaction confirmation latency of blockchain-based cryptocurrencies.
by Emin Gün Sirer on August 03, 2016 at 07:20 AM
The Bitfinex attack, and similar heists from Bitcoin exchanges, are preventable with a small extension to Bitcoin.
by Emin Gün Sirer on July 19, 2016 at 06:15 PM
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.
by Emin Gün Sirer on July 17, 2016 at 12:07 PM
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.
by Emin Gün Sirer on July 13, 2016 at 10:45 AM
Reentrancy bugs are difficult to catch. This distilled, illustrative example shows how even a diligently-written contract with invariant checks can go wrong.
by Ittay Eyal and Emin Gün Sirer on July 11, 2016 at 02:42 PM
We describe a general Decentralized Escape Hatch mechanism, suitable for DAOs and other smart contracts.
by Tjaden Hess, River Keefer, and Emin Gün Sirer on July 05, 2016 at 01:14 PM
Our discovery of a DoS vulnerability in Ethereum turns out to be a point of strength and censorship resistence for the currency.
by Tjaden Hess, River Keefer, and Emin Gün Sirer on June 28, 2016 at 09:22 AM
We identify a DoS vulnerability with Ethereum's proposed soft-fork for The DAO, and urge the community to be prepared for attacks, and to speed up the timetable for resolving the hard fork decision.
by Bill Marino on June 23, 2016 at 10:11 AM
IC3's resident lawyer-techie discusses why smart contracts need escape hatches and how to implement them.
by Phil Daian on June 18, 2016 at 01:11 AM
This post describes how the hacker who took $50+M from The DAO did it.
by Emin Gün Sirer on June 17, 2016 at 09:45 AM
The DAO was just hacked and a few million ether is missing. Here are my quick thoughts on what this means and where we go from here.
by Zikai Alex Wen and Andrew Miller on June 16, 2016 at 01:15 PM
In this post, we examine just how prevalent the recently discovered "unchecked-send" bug is in real, live, deployed Ethereum contracts, with the aid of an automated analysis tool we have developed.
by Emin Gün Sirer on June 13, 2016 at 09:15 AM
The DAO is under pressure to turn itself into a Ponzi. I explain the "natural-born Ponzi" mechanisms, and call for the community to be on guard for such proposals.
by Dino Mark, Vlad Zamfir, and Emin Gün Sirer on May 27, 2016 at 01:35 PM
We just published a draft article, urging a moratorium on The DAO until some security patches can be applied.
by Emin Gün Sirer on May 04, 2016 at 09:40 AM
I point out some of the pitfalls I see my colleagues fall into as Craig Wright's Satoshi saga unfolds.
by Emin Gün Sirer on May 02, 2016 at 04:00 PM
Craig Wright has made yet another claim to be Satoshi Nakamoto. This post describes what it takes to make a credible claim.
by Christian Decker and Emin Gün Sirer on April 29, 2016 at 08:48 AM
There was a bitcoin transaction carrying a $137K fee. This posts examines why transactions might carry such large fees, and rules out some explanations.
by Emin Gün Sirer on April 25, 2016 at 08:48 AM
There was a series of heists at ShapeShift, followed by an offered explanation. That offered explanation has more holes in it than Swiss cheese.
by Emin Gün Sirer on April 25, 2016 at 08:48 AM
There was a series of heists at ShapeShift, followed by an offered explanation. That offered explanation has more holes in it than Swiss cheese.
by Emin Gün Sirer on April 05, 2016 at 10:55 AM
My take on how software gets bloated, using a cautionary tale from the telephony world, with applications to Bitcoin.
by Emin Gün Sirer on March 01, 2016 at 12:15 PM
Some people claim that Bitcoin is eventually consistent. They are wrong. This post tries to dispel the myth and explain the right way to evaluate the consistency guarantees of distributed systems.
by Malte Möser, Ittay Eyal, and Emin Gün Sirer on February 29, 2016 at 01:15 PM
Bitcoin vaults have the potential to stop Bitcoin thefts from Bitcoin clients. This post answers some frequently asked questions about them.
by Malte Möser, Ittay Eyal, and Emin Gün Sirer on February 26, 2016 at 09:00 AM
We have come up with a simple and elegant technique for implementing hack-proof Bitcoin vaults, to deter Bitcoin thefts.
by Emin Gün Sirer on January 05, 2016 at 10:40 AM
Evidently, a requirement for becoming a CEO at a Bitcoin exchange or payments company is to believe that your company has no power and works entirely at the discretion of the miners. I try once again to correct this myth.
by Emin Gün Sirer on January 01, 2016 at 03:40 PM
I make the case that Bitcoin users have just as much of a say, or more, than all the miners combined. They wield this power through exchanges, and the exchanges need to live up to their responsibilities.
by Emin Gün Sirer and Ittay Eyal on December 30, 2015 at 09:30 AM
In an effort to bring the fruitless Bitcoin block size debate to a close, this post outlines Bitcoin-Unified, an approach to accommodate both small and large blocks.
by Emin Gün Sirer on December 23, 2015 at 11:00 AM
The phrase "developing the fee market" gets used a lot in Bitcoin circles. This post makes the case that this is a thinly veiled euphemism for jacking up the fees.
by Emin Gün Sirer on December 22, 2015 at 01:30 PM
Some people say that "if Bitcoin relies on altruism, then it has already failed." Bitcoin relies heavily on altruism, and it has not failed.
by Emin Gün Sirer on December 16, 2015 at 03:30 PM
I try to lay to rest a bad way to account for Bitcoin network costs and a flawed argument for exorbitantly high fees.
by Emin Gün Sirer on December 10, 2015 at 11:43 AM
The press is doing a fresh manhunt for Satoshi again. This post focuses on one of the effective techniques to recognize Satoshi if he were to walk among us.
by Emin Gün Sirer on December 02, 2015 at 02:13 PM
Peter Tschipper has been looking into compressing the Bitcoin messages on the wire using generic compressors. In this post, I discuss why generic compressors will not work well with Bitcoin, make the case for a custom compressor, and suggest that we run a community challenge to develop the best compressor.
by Emin Gün Sirer on November 13, 2015 at 12:08 PM
A modest suggestion on how to proceed with the block size debate, wherein we suggest explicitly defining the criteria for evaluating block size increase proposals.
by Ittay Eyal and Emin Gün Sirer on November 09, 2015 at 12:08 PM
We review some of the feedback we received on Bitcoin-NG and discuss why every new permission-less ledger would be better off with NG compared to the alternatives.
by Ittay Eyal and Emin Gün Sirer on October 14, 2015 at 01:05 PM
We introduce a new technique for increasing the throughput and reducing the latency, at the same time, of blockchain-based protocols
by Ittay Eyal on December 03, 2014 at 12:15 PM
In a new analysis of Bitcoin mining, Ittay Eyal shows that the equilibrium between miners is unstable, and identifies a stable equilibrium that might, as a side effect, reduce the size of open, public mining pools.
by Emin Gün Sirer on June 19, 2014 at 05:56 PM
This is a quick blog post to dispel a common Bitcoin misconception/myth involving voting power.
by Ittay Eyal and Emin Gün Sirer on June 18, 2014 at 02:03 PM
We outline a small change to the Bitcoin mining protocol that rules out big, public mining pools. It preserves the current investment in Bitcoin by both existing users and by existing miners. It presents a fix to GHash's recent 51% excursion.
by Ittay Eyal and Emin Gün Sirer on June 16, 2014 at 02:35 PM
There seems to be a lot of confusion over the kinds of attacks that a Bitcoin mining monopoly can engage in. We clarify the space of attacks available to a Bitcoin mining monopoly.
by Emin Gün Sirer on April 06, 2014 at 12:15 PM
The real story of how weak NoSQL systems allowed users to make money out of the thin air and brought down two Bitcoin exchanges, one permanently.
by Emin Gün Sirer on April 05, 2014 at 05:00 PM
A quick summary of the red flags that preceded the demise of Neo & Bee, the latest Bitcoin startup from Cyprus.
by Emin Gün Sirer on March 01, 2014 at 09:35 AM
There are lots of theories about what may have happened at Mt. Gox. This post examines what may not have happened, and how to avoid that which did happen.
by Ittay Eyal and Emin Gün Sirer on January 15, 2014 at 12:25 PM
How to detect when someone in the network is engaged in selfish mining
by Ittay Eyal and Emin Gün Sirer on January 01, 2014 at 11:13 PM
BTC Guild released a number of blocks in quick succession, making some people worry that they are selfish mining. We discuss the evidence.
by Robert Escriva on November 27, 2013 at 04:53 PM
Bitcoin was having problems with LevelDB. We identified and fixed the bug. In this article, we'll talk a little about LevelDB, Bitcoin, and our fix.
by Ittay Eyal and Emin Gün Sirer on November 25, 2013 at 03:15 PM
New measurements show that successful selfish mining attacks are quite feasible.
by Giray Pultar, Selcuk Pultar, and Emin Gün Sirer on November 21, 2013 at 07:53 AM
Bitcoin's unique features allow it to be used to for social causes. A cash boycott is one such way to affect social change.
by Ittay Eyal and Emin Gün Sirer on November 17, 2013 at 02:40 PM
There is now a visual simulator for our selfish mining attack.
by Ittay Eyal and Emin Gün Sirer on November 14, 2013 at 09:45 AM
There have been some early, and often misplaced, responses to the vulnerabilities we discovered in the Bitcoin system. This post addresses them.
by Ittay Eyal and Emin Gün Sirer on November 08, 2013 at 11:21 AM
Fairweather mining has been suggested to argue that selfish mining would be a short-lived strategy, but fairweather mining analysis is flawed because it does not take proofs of work into account.
by Ittay Eyal and Emin Gün Sirer on November 05, 2013 at 10:30 AM
Some clarifications and answers to frequently asked questions about the selfish mining attack on Bitcoin.
by Ittay Eyal and Emin Gün Sirer on November 05, 2013 at 10:30 AM
If the health of your cryptocurrency requires Gordon Gekko to make sacrifices, it is doomed.
by Ittay Eyal and Emin Gün Sirer on November 04, 2013 at 10:30 AM
We discovered an attack against the Bitcoin mining protocol that can have a significant impact on the Bitcoin community.