Editing Timechain (section)

== Author commentary ==
We first published our work on "timechains" on '''Saturday, 20 June 2015''' -- as of 2025 that's more than 10 years ago. The timechains paper described how sequential hashing could be used to delay the release of time-lock encrypted ECDSA keys. The neat thing about this was these keys were compatible with the blockchain systems at the time. So you could create smart contract schemes that needed time-locked transactions using a timechain -- at least that was the idea.

Timechains might have been the first mention of using a deterministic, lengthy, sequential function to delay an event in a blockchain context. The name for such functions ended up becoming known as '''"verifiable delay functions."''' So where are VDFs at today? Well, last I checked they were still grappling with the very same issues this paper raises: which is that its very hard to design a VDF whose execution will remain consistent across a wide number of platforms. VDFs have found their way into some blockchain protocols. The one that stands out to me is Filecoins use of VDFs to prove that information remains stored over time.

I'm unsure if Filecoin still uses VDFs; if its efficient; or if they've managed to solve the issues with VDFs.