3 ms·
So a hash chain. This prevents someone from arbitrarily changing a particular historical value in isolation, but there's nothing preventing the database operato
by DennisP 6y ago
So a hash chain. This prevents someone from arbitrarily changing a particular historical value in isolation, but there's nothing preventing the database operator from making a change and regenerating all the hashes from scratch.
The article didn't address that threat. One defense would be to make the entire hash chain available, and let a third party verify that it hasn't changed. Of course you could also replicate the entire database to the third party, so you're just gaining some efficiency and privacy (which might be worthwhile in some cases).
A blockchain on the other hand makes data really immutable. You can't change the data without doing an enormous amount of work, or (more recently) losing a large amount of staked currency.
- jonathanaird 6y agoExactly. This is no fundamentally different than a traditional time-stamping service. If the time-stamping service is compromised, all of the previous timestamps are invalid. The only alternative to a blockchain is to publish the latest hash widely in a verifiable place such as in a well-known newspaper.
- eli 6y agoAren't there lots of "private blockchains" that work this way? It's basically just a database that is made available for others to audit.
- jonathanaird 6y agoYes, it’s just old companies like IBM trying to ride a buzz wave. The whole point of a blockchain is that it’s public and verifiable.
- eli 6y agoIMHO they've correctly assessed the situation that the buzz is the most important feature.
- jonathanaird 6y agoTouche. It’s so hard to get past the buzz in crypto because people are making way too much money on the price of tokens. It’s so distracting. I think we’ll get there eventually.