For the last article of the day, I want to talk to you about a new mandatory WorldCoin client update that was just announced. Updating must be done before or on May 31st, so make sure you grab the latest version as soon as possible.
What’s new in Worldcoin v0.8.6.2?
Automatic Checkpointing – Advanced protection against 51% attacks
Graphic updates to the wallet
Reduced time warp exploit from 2 hours to 15 minutes. Prevents multi-pools and other large miners from abusing difficulty re-adjustment to a great extent.
Reduced influence of nodes on blockchain time to 11 minutes down from 35 minutes.
Fixed Heartbleed vulnerability
Updated new DNS seed nodes to increase reliability in finding peers
Miscellaneous bug fixes and fixed translations
What is Automatic Checkpointing?
Automatic Checkpointing is a security mechanism that provides protection against 51% attacks. As multi-pools (mining pools that have the ability to move a large amount of hashing power between different currencies) have gained in total hashing power and Scrypt-based ASIC’s are quickly becoming a reality, the likelihood of a successful 51% attack increases. Such an attack would have the ability to block transactions from being confirmed and allow double spending, and could potentially have long term damaging effects on the Worldcoin network and currency.
How does Automatic Checkpointing work?
Automatic Checkpointing works by designating one “master node” on the network which routinely publishes checkpoints as blocks are solved. A checkpoint is simply a block hash that is known to be part of the blockchain at a given point in time. The master node relays the checkpoint to all nodes on the network and each node validates that the checkpoint exists in their local blockchain. Each node also validates that the checkpoint is not older than the previous checkpoint, and is a descendent of the previous checkpoint as well. If the blockchain should fork due to a 51% attack, the checkpoint system will allow each node to reject the forked chains blocks, because the checkpoint blocks won’t be a part of the 51% fork.
Does that mean Worldcoin is turning into a centralized currency?
No, Worldcoin is still a decentralized currency where transactions are independently validated by every node on the network and blocks are mined by individual miners. The checkpointing system is used solely as a safety mechanism in the event of an intentional attack on the network. The master node is controlled by the Worldcoin development team – it does not have the ability to generate coins at will, spend other peoples coins, or reverse transactions prior to a fork occurring. It simply keeps a historical record of which blocks were in the chain at a certain point of time in order to detect and correct the network should a 51% attack occur.
I want to upgrade but I’m concerned about Automatic Checkpointing.
Automatic Checkpoint enforcement is enabled by default in 0.8.6.2, however you can easily disable it by including “checkpointenforce=0″ in your configuration file or issuing the command “enforcecheckpoints false” at the debug window or command line. Note the second command line method will only make this change for your current session – you will need to issue the command each time you restart the client. You can check if enforcement is enabled by issuing the command “getcheckpoint” in the debug window or command line. “subscribemode” with either be “enforce” or “advisory” – in advisory mode you will be advised if the checkpoint system has detected a fork, but your client will not reject blocks that are part of that fork.
Why is this Update Mandatory?
The time Warp exploit will be reduced from 2 hours down to 15 minutes on block 1,316,550; approximately May 31, 2014. When this happens if you are on an old client it is very likely that you will end up on the wrong blockchain. The most likely outcome of this is that your client will stop working. In order to prevent any disruption in your ability to send and receive WDC it is recommended that you upgrade now.