Security Advisory [Implementation bugs in Go and Python clients can cause DoS – Fixed – Please update clients]

State transition and consensus issue in geth client causes panic (crash) when processing a (valid) block with a specific combination of transactions, which may cause overall network instability if block is accepted and relayed by unaffected clients thus causing a DoS. This may happen in a block that contains transactions which suicide to the block reward address. Affected configurations: Issue reported for Geth.While investigating the issue, related issues were discovered and corrected in pyethereum, hence pyethapp is also affected. C++... [Read More]

devcon one postponed until further notice

Unfortunately we were not able to secure the venue for devcon one in London on the dates desired (October 5th-8th). As a consequence we are postponing the event until further notice.  Please do not make travel plans at this time. Updates will be forthcoming on the devcon one website . Please standby for further information.

Security Advisory [Insecurely configured geth can make funds remotely accessible]

Insecurely configured Ethereum clients with no firewall and unlocked accounts can lead to funds being accessed remotely by attackers. Affected configurations: Issue reported for Geth, though all implementations incl. C++ and Python can in principle display this behavior if used insecurely; only for nodes which leave the JSON-RPC port open to an attacker (this precludes most nodes on internal networks behind NAT), bind the interface to a public IP, and simultaneously leave accounts unlocked at startup. Likelihood: Low Severity: High... [Read More]

On Anti-Pre-Revelation Games

An increasing number of proposed applications on top of Ethereum rely on some kind of incentivized, multi-party data provision - whether voting, random number collection, or other use cases where getting information from multiple parties to increase decentralization is highly desirable, but also where there is a strong risk of collusion. A RANDAO can certainly provide random numbers with much higher cryptoeconomic security than simple block hashes - and certainly better than deterministic algorithms with publicly knowable seeds, but it... [Read More]

Olympic Rewards Announced

ETH DEV would like to thank everyone for their participation in the Olympic test network, which helped us greatly in stress testing, optimization, and finding bugs in the Ethereum clients, as well as determining what the limits of the current Ethereum system are. To that end, we are pleased to announce the Olympic reward recipients. On top of the rewards announced below, every miner who mined a block in the Olympic chain with block number in the range [310000, 589999]... [Read More]

Security alert [consensus issue]

This alert is related to a consensus issue that occurred on the Frontier network at block 116,522, mined on 2015-08-20 at 14:59:16+02:00 – Issue has been fixed, see “Fix” below. Impact: High Issue description: State database consensus issue in geth with deletion of account data, which could happen during SUICIDE instructions. Affected implementations: All geth implementations up to and including versions 1.0.1, 1.1.0 and develop (“unstable 1.1.0”) were affected. Eth (C++) and pyethereum (Python) are unaffected. Effects on expected chain reorganisation depth:... [Read More]

An Analysis of the First 100000 Blocks

After a successful launch, Frontier passed it’s 100000th block earlier this week. Here are some interesting stats from these first blocks. The first 50 block times (in seconds): Right after genesis, it took 29 seconds for the second block to appear, then 31 and 29 seconds for the next couple of blocks. Not too surprising as the miners scrambled with their setups as the final genesis block became known. After these first blocks, we see the block time drop significantly... [Read More]

Chain Reorganisation Depth Expectations

This following shows our current and planned expectations concerning maximum likely chain-reorganisation depth. We would not consider transactions within this depth to have an exceptionally high chance of being permanent. These are our own expectations only and do not constitute any sort of guarantee. They are derived from theoretical considerations, ongoing empirical data, human factors in contingency planning and the past experience of our security team. As with all things in the peer-to-peer space the risk is entirely with the... [Read More]

Security Alert 1 [windows+alethzero]

This affects users of Alethzero GUI client on Windows. Users of eth CLI client or not on the Windows platform are unlikely to be affected but should take action detailed below. Users of Frontier command line interface geth are unaffected. Issue description: While setting privacy permissions on the keys directory, insufficient error handling can cause the key files to not be written; this may be widespread on the Windows platform. As such, current versions of AlethZero and eth may include identities... [Read More]

On Public and Private Blockchains

Over the last year the concept of “private blockchains” has become very popular in the broader blockchain technology discussion. Essentially, instead of having a fully public and uncontrolled network and state machine secured by cryptoeconomics (eg. proof of work, proof of stake), it is also possible to create a system where access permissions are more tightly controlled, with rights to modify or even read the blockchain state restricted to a few users, while still maintaining many kinds of partial guarantees... [Read More]