Solidity was started in October 2014 when neither the Ethereum network nor the virtual machine had any real-world testing, the gas costs at that time were even drastically different from what they are now. Furthermore, some of the early design decisions were taken over from Serpent. During the last couple of months, examples and patterns that were initially considered best-practice were exposed to reality and some of them actually turned out to be anti-patterns. Due to that, we recently updated...

Affected configurations: cpp-ethereum (eth, AlethZero, …) version 1.2.0 up to 1.2.6 Note: Neither “geth” nor “Mist” nor the “Ethereum Wallet” (unless explicitly used together with cpp-ethereum) are affected by this, they lock accounts correctly again. This is just a quick head’s up that cpp-ethereum’s security issue around account security is not yet properly fixed. The fix that is part of cpp-ethereum version 1.2.6 did not decrease the security, but it also did not fix the bug completely. We will work...

The Ethereum Virtual machine is kind of different than most other Virtual Machines out there. In my previous post I already explained how it’s used and described some of its characteristics. The Ethereum Virtual Machine (EVM) is a simple but powerful, Turing complete 256bit Virtual Machine that allows anyone to execute arbitrary EVM Byte Code.</blockquote> The go-ethereum project contains two implementations of the EVM. A simple and straightforward byte-code VM and a more sophisticated JIT-VM. In this post I’m going to explain some of the differences...

Affected configurations: cpp-ethereum (eth, AlethZero, …) version 1.2.0 up to 1.2.5 (fixed in 1.2.6) Note: Neither “geth” nor “Mist” nor the “Ethereum Wallet” (unless explicitly used together with cpp-ethereum) are affected by this, they lock accounts correctly again.</section><section class="postbody"></section><section class="postbody">Severity: High</section><section class="postbody"></section><section class="postbody">Possible Attacks: Attackers can spend funds from previously used accounts if they have access to the local machine or to an exposed json-rpc interface.</section><section class="postbody"></section><section class="postbody">Details: Due to a bug in cpp-ethereum, accounts stay unlocked once their password...

Affected configurations: All Go client versions  Likelihood: Very low Severity: High Details: A bug in Geth (and potentially other clients) may suffer from a DoS attack and allows remote attackers to stall synchronisation process almost indefinitely by supplying a valid, lighter chain. More information will be given out a later time including the report that was submitted through the bug bounty program. Effects on expected chain reorganisation depth: None Proposed temporary workaround: None Remedial action taken by Ethereum: Provision of hotfixes as below: If you’re using Mist:...

Special thanks to Tim Swanson for reviewing, and for further discussions on the arguments in his original paper on settlement finality. Recently one of the major disputes in ongoing debate between public blockchain and permissioned blockchain proponents is the issue of settlement finality. One of the simple properties that a centralized system at least appears to have is a notion of “finality”: once an operation is completed, that operation is completed for good, and there is no way that the...

After almost three months into the “reboot” of the C++ team, I would like to give an update about the team itself, what we did and what we plan to do. Team update The so-called C++ team currently consists of Paweł Bylica (@chfast), Greg Colvin (@gcolvin), Liana Husikyan (@LianaHus), Dimitry Khokhlov (@winsvega), Yann Levreau (@yann300), Bob Summerwill (@bobsummerwill), me (@chriseth) and (kindly “donated” by Eris Industries) RJ (@VoR0220). Paweł is the original author of the llvm-based EVM-to-native just-in-time compiler, re-joined in...

[Last update: July 5, 2016] The Ethereum Foundation and Wanxiang Blockchain Labs are excited to jointly announce the International Blockchain Week in Shanghai, which will take place at Hyatt on the Bund, September 19–24, 2016. Both Ethereum’s Devcon and Wanxiang Blockchain Labs’ Global Blockchain Summit were sold out last year with great interest and anticipation for this year’s events. Now, people who wish to attend both events can do so in the same week. The combined event features a unique...

The Ethereum Foundation has announced that it will be working with the New York-based banking consortium R3CEV on creating a new blockchain-based cryptocurrency, Lizardcoin, which aims to showcase the benefits of blockchain technology as well as the consortium’s ability to bring the technology to institutional clients and the regulation-loving masses by supplementing it with a healthy dose of centralized control. Lizardcoin aims to be a direct competitor to Bitcoin as a store-of-value, beating out Bitcoin’s 21 million fixed supply cap...