Few understand this ⏳
Discussion
It's called "weak synchrony".
The Time Warp Attack, which was hypothetical, was implemented effectively against the Verge cryptocurrency, which succeeded in pausing the chain and allowing the attacker to issue as many blocks as they wanted to until the node runners shut them down.
The vulnerability that enabled this was an attempt to tighten the synchrony of the network, by, specifically, nodes adjusting their time offset to a tight margin of the average of the swarm.
All that was required was for one node to continuously poke at the network's measure of time until all nodes agreed there was no progress of time, and the attack basically then shut down the network.
The lesson of this story is that you can't make a consensus out of the time, without breaking the difficulty adjustment.
Thanks for this explanation
Always love your thoughts and writings on time.
Algorithms are beautiful
I think this vulnerability is not overcome in a proof-of-stake protocol without centralization.
Yeah, I don’t get it.
Maybe you can suggest some writings so that Many understand this. I didn’t get it. ☹️
A great in depth read. Great to revisit.
I didn’t know this was how “network adjusted time” was defined, do you have any wiki or stack exchange links on this? It makes sense, but it does seem vulnerable to an eclipse attack (by a sophisticated miner, or someone just trying to cause havoc).
On the “median timestamp”, I recently went down a rabbit hole on this. It finally made sense when I realized that in a perfect scenario of exactly 10min block intervals, the median timestamp of the prev 11 blocks is 60min prior. 🤯