How does that work exactly? Does it all still hinge on trusting a know Time Stamp Authority, or is there some way of time stamping in a trustless manner?
https://www.imperialviolet.org/2016/09/19/roughtime.html
https://int08h.com/post/to-catch-a-lying-timeserver/
This proves you generated it before this time.
You can also include in the hash the close of the stock market and all the sports scores from the previous day. That proves you generated it after that time.
Sports sports are an interesting source of entropy.
You are relying upon the authority of the beacon to be random, but good practice is to utilize multiple independent beacons.
[0] https://csrc.nist.gov/projects/interoperable-randomness-beac...
Not so useful if something was edited a few minutes after posting, but it makes it more difficult for a new administration to suddenly edit a bunch of old data.
But you could do the same thing with any hashes, right? There is no need for a blockchain in the middle.
There’s also a size advantage. You can keep a diff on the archive for each hash being posted instead of the full index for every time you post a hash.
Still, Open Timestamps does exactly this, and had been running for over 8 years now.
The chance is exceedingly low that the PKI infrastructure of all the authorities becomes compromised.