Because many companies with many conflicting interests need to be able to trust each other. If we put this data in a database, our enterprise customer can tweak the system to their advantage if they make a deal with us.

The global, open database provided by a blockchain solves this problem, and also allows anybody to read the state without relying on our company to maintain the database or for uptime.

So the customer set up an IT service with multiple servers to sync with yours so that both can sync to the ledger? How does that work in practice? Is someone also monitoring that nobody is doing a 50% attack? Are both parties present when something is inserted into the blockchain?

Hmm, I'm not quite sure what you're trying to ask.

In the aforementioned case, the pickup time in known, so all that matters is that the photos are timestamped before or at pickup time. We don't worry about 51% attacks because we use the Stellar blockchain, also used by Franklin Templeton investments and IBM and Keybase... The chance of a 51% attack going unnoticed is virtually zero.

The ledger is public, and anyone can view the history of the ledger using Stellar's API (a hosted version is available at https://horizon.stellar.org) or a blockchain explorer like https://stellar.expert.

The great thing is that the data is stored on a distributed series of nodes, so no syncing is needed.

In some examples I've seen non-public ledgers, with X nodes run by the same company. And then they claim "we use blockchain so we're tamper-proof!"

Is your organization unusually susceptible to that kind of corruption? It seems like blockchain or no, the clients have to trust that you'll provide the service you agreed to and not cash their checks and disappear etc.

No.

But how are the many other people in the auto supply chain supposed to know that? With this solution, they don't have to trust our company, just the SHA256 hashing algorithm.

Math is easier to trust than a small startup.

Edit: To clarify, many of the people checking against the blockchain record are not our clients.

Call me cynical but I'm still confused by this.

If the issue is that people are taking cars for joyrides why not just have the car post a route file to a database or to its own computers of all the trips. Are auto suppliers really taking joyrides AND hacking into the computers? If you are capable enough to do that wouldn't it also stand to reason you'd be capable enough to disable any tracking units?

That sounds ridiculously impractical, and far more technologically complex and time-consuming than the solution we've built. You're free to compete with us though — I'd be interested to see how you manage the route files, how you make sure that the database is neutrally controlled, how you use the car computer to determine whether or not there's a dent in the car body...

Because the person who owns the database has to be trusted, where here no one has to be

In GP's example, the "person who owns the database" is already trusted because they wrote the software. The software can insert lies into the blockchain very easily.

I'd also argue that the "person who owns the database" is not just trusted but also trustworthy. They have an incentive to keep lies out of the data.

If the people you can't trust are your users, then blockchain doesn't really add anything. They can insert lies, and you have to verify them. All you get is a guarantee that no one changed their lies to something else.

This is not true. You are always trusting someone. <-- that is a really really big period. In this case you are trusting the authors of the code which this process runs on. The machines that this code runs on. And last but not least the fact that no one has control over majority of the nodes. You are always trusting someone or something.