According to cryptocurrency influencer and educator Andreas Antonopoulos, Dash’s ChainLocks is “a smart way of” securing a blockchain network against 51% attacks.
Make sure to watch full video 🙂👍
— Mark Mason (@StayDashy) August 22, 2019
During a recent question and answer session released earlier this week on his YouTube channel, Antonopoulos was asked about Dash’s recent implementation of ChainLocks for advanced network security. He responded with an in-depth description, and called the solution “a novel and interesting way to” approach network security by combining the benefits of proof-of-work (PoW) and proof-of-stake (PoS) systems:
“Essentially what that does is it creates a hybrid proof-of-work/proof-of-stake system. You can’t attack the proof-of-work with a 51% attack because the masternodes are checkpointing with a vote using threshold signatures, and once 60% agree on the current state of the chain, that locks in that chain with a checkpoint. It’s a novel and interesting way to do a hybrid proof-of-work/proof-of-stake system, and yes, it will make 51% attacks much harder on that particular chain. In fact, if you want to do a 51% attack, you actually have to do a 60% attack where you either compromise the code running on the masternodes, or you put enough stake, which probably wouldn’t be possible, to run 60% of the masternodes yourself. I think at current rates that would be like $300 million, so that’s not feasible.”
While technically proof-of-service (PoSe) due to its emphasis on performance standards for nodes rather than staking units of the currency, Dash nevertheless leverages the requirement of ownership of 1,000 Dash in order to run a masternode, making the network resistant to sybil attacks in the form of spinning up a host of attacking nodes. ChainLocks was activated at the beginning of July this year, and Dash Core CEO Ryan Taylor has hailed the innovation as making Dash more secure than Bitcoin. In addition to security benefits, ChainLocks may also remove many more minor issues facing PoW networks.
The low hashrate PoW problem
According to Antonopoulos, PoW currencies are inherently vulnerable to attack before becoming sufficiently established due to the low amount of hashrate on the network:
“The primary reason Dash and Zcoin are doing it is that we’ve seen again and again and again that systems that have proof-of-work that have enormous hashrates and use ASICs, like Bitcoin, are very difficult and expensive to attack with a 51% attack, so they’re not attacked. But systems with lower hashrate, or have hashrate that depends on GPUs, not ASIC-based mining, then people can switch GPU mining from other chains, and attack a chain that’s a bit weaker in its hashing power quite effectively. We’ve seen 51% attacks against Ethereum Classic, I believe Zcoin had a 51% at some point.”
He emphasized that this was not a critique of the projects themselves, only an exploration of the game theory system and its effects on chains where a relatively low amount of effort can net potentially higher gains:
“I’m not attacking these chains by saying this, it just means that proof-of-work systems are indeed vulnerable when they are brand new and they don’t have enough hashing power to make it prohibitively expensive. A chain can only be secure with proof-of-work if the cost of attacking it far, far exceeds the potential benefits of attacking it. It’s a game theory system. So if the cost of attacking it doesn’t exceed the potential gains, then it will, and does, get attacked, and we’ve seen this happen again and again on weaker chains. We haven’t seen it happen in Bitcoin.”
Worthy of note is that coins sharing an algorithm with a more established project, such as the case of Bitcoin Cash and Bitcoin SV, have an inherent vulnerability in that entities potentially without a vested interest in those particular projects possess the power to significantly disrupt their networks. In the case of a currency like Bitcoin or Dash, each one represents the significant majority of the hashpower directed at their respective mining algorithms, SHA256 and X11. This makes an attack attempt much less likely due to the incentives inherent in protecting the value of an investment in mining equipment which would likely become obsolete in the case of the network collapsing, providing robust security even before ChainLocks was introduced.
A solution that combines the best of PoW and PoS models
Finally, Antonopoulos focused in on why ChainLocks makes sense for protecting coins with less than Bitcoin’s hashrate by leveraging the best of both PoW and PoS systems, avoiding either one’s individual vulnerabilities, calling it “a smart way of doing it”:
“In that case, if you have a chain that doesn’t have enough hashing power to make it completely cost-ineffective to attack, then you need something else to buttress that, and that’s essentially what ChainLocks is doing here: it’s a hybrid proof-of-work/proof-of-stake system. And it’s a smart way of doing it, because instead of having a proof-of-stake system on its own, which is vulnerable to historical immutability attacks, or a proof-of-work system, that without enough hashpower is vulnerable to 51% attacks, by combining them you have a system that defends better against 51% attacks than proof-of-work, and defends better against historical immutability attacks than proof-of-stake. A good solution for a system like Dash.”