Security alert [12/19/2016]: Forums Database Compromised

On December 16, we were made aware that someone had recently gained unauthorized access to a database from We immediately launched a thorough investigation to determine the origin, nature, and scope of this incident. Here is what we know: The information that was recently accessed is a database backup from April 2016 and contained information about 16.5k forum users. The leaked information includes Messages, both public and private IP-addresses Username and email addresses Profile information Hashed passwords ~13k bcrypt... [Read More]

Swarm alpha public pilot and the basics of Swarm

With the long awaited geth 1.5 (“let there bee light”) release, Swarm made it into the official go-ethereum release as an experimental feature. The current version of the code is POC 0.2 RC5 – “embrace your daemons” (roadmap), which is the refactored and cleaner version of the codebase that was running on the Swarm toynet in the past months. The current release ships with the swarmcommand that launches a standalone Swarm daemon as separate process using your favourite IPC-compliant ethereum... [Read More]

The History of Casper – Chapter 2

This chapter describes the game theory and economic security modelling we were doing in the Fall of 2014. It recounts how the “bribing attacker model” led our research directly to a radical solution to the long range attack problem. Chapter 2: The Bribing Attacker, Economic Security, and the Long Range Attack Problem Vitalik and I had each been reasoning about incentives as part of our research before we ever met, so the proposition that “getting the incentives right” was crucial... [Read More]

The History of Casper — Chapter 1

Vitalik suggested last week that I share my basic research and design philosophy in a blog post, I agreed but complained that it was still changing. My friend Jon West told me that everyone would really appreciate it if I told everyone about my Casper research, I mostly agreed. Then someone on reddit told me to focus on Ethereum. So here’s the Casper tech story, given as a chronological history of the evolution of the key technology, ideas and language... [Read More]

zkSNARKs in a nutshell

The possibilities of zkSNARKs are impressive, you can verify the correctness of computations without having to execute them and you will not even learn what was executed - just that it was done correctly. Unfortunately, most explanations of zkSNARKs resort to hand-waving at some point and thus they remain something “magical”, suggesting that only the most enlightened actually understand how and why (and if?) they work. The reality is that zkSNARKs can be reduced to four simple techniques and this... [Read More]

Ethereum Research Update

This week marks the completion of our fourth hard fork, Spurious Dragon, and the subsequent state clearing process, the final steps in the two-hard-fork solution to the recent Ethereum denial of service attacks that slowed down the network in September and October. Gas limits are in the process of being increased to 4 million as the network returns to normal, and will be increased further as additional optimizations to clients are finished to allow quicker reading of state data. In the midst of... [Read More]

Security alert [11/24/2016]: Consensus bug in geth v1.4.19 and v1.5.2

Security Alert Affected configurations: Geth Severity: High Summary:  An issue has been identified with Geth’s journaling mechanism. This caused a network fork at block #2686351 (Nov-24-2016 14:12:07 UTC). The new Geth release 1.5.3 fixes the journaling issue and repairs the fork. Details: Geth was failing to revert empty account deletions when the transaction causing the deletions of empty accounts ended with an an out-of-gas exception. An additional issue was found in Parity, where the Parity client incorrectly failed to revert... [Read More]

Hard Fork No. 4: Spurious Dragon

The Ethereum network will be undergoing a hard fork at block number 2,675,000, which will likely occur between 15:00 and 16:00 UTC on Tuesday, November 22, 2016. A countdown timer can be seen at The Morden test network will be undergoing a hard fork at block number 1,885,000. [Read More]

Whoa… Geth 1.5

The Go Ethereum team is very proud to finally release Geth 1.5, which can almost be called a complete internal rewrite of the Go Ethereum (go-ethereum) codebase. We’ve packed a huge number of changes into this release, and simply listing them wouldn’t do them justice. Instead, we’ve decided to write them up in a more informal way, explaining not only what’s new, but also why it’s needed, and why it’s awesome! Go Ethereum website The go-ethereum project never really had a website. There... [Read More]