[yellowapple]

The advantages start popping up when multiple DMVs are using the same ledger; they don't have to trust each other, yet can still read and write records. The end game would be for state DMVs, international DMVs, and even private entities to be able to share information on a vehicle and its history - think CarFax, but much broader in scope and without some corporation acting as a middleman.

In this sense, I'm a bit skeptical of the value add of California's implementation, despite "put car titles on the blockchain" being something for which I've advocated for years now. This would've made more sense as a multi-state partnership.

[Zanfa]

This makes zero sense.

> The advantages start popping up when multiple DMVs are using the same ledger; they don't have to trust each other, yet can still read and write records.

What do you mean different DMVs don’t have to trust each other? If California DMV can’t trust data written by Nevada DMV, what’s the point of writing it in the first place?

> The end game would be for state DMVs, international DMVs, and even private entities to be able to share information on a vehicle and its history - think CarFax, but much broader in scope and without some corporation acting as a middleman.

Okay, but who is responsible for verifying all of the data coming in from random 3rd parties? If you wanna get a good deal on a used car being sold, just submit a fake entry about it having been totaled in an accident. Instant discount!

And not to mention all of the PII that’s core to DMV’s operations that can’t be public, so it can’t be on a public blockchain anyway.

[yellowapple]

I think we're talking about different senses of the word "trust". I'm more referring to it in the sense of "I trust you to competently administer this database and not tamper with its data" rather than in the sense of "I believe the the data you're committing to be accurate".

The former is what a (public) distributed ledger solves; a central authority is problematic even in interstate contexts, let alone international. Blockchains don't directly solve the latter, but do provide tools for tackling it - namely, by making the submitted data trivial to audit. Using your example:

> If you wanna get a good deal on a used car being sold, just submit a fake entry about it having been totaled in an accident. Instant discount!

Setting aside the immediate footgun here (since you've nerfed whatever resale value you'd hope to get out of it), your single datapoint is less believable than the concurrent agreement of:

- A police department noting "a vehicle with this VIN was involved in an accident"

- An insurance company noting "we paid out an insurance claim for a vehicle with this VIN"

- A towing company noting "we towed a vehicle with this VIN to a repair shop"

- A repair shop noting "we serviced a vehicle with this VIN"

In short: there are a lot more opportunities for verifying information when it's on a public ledger than there are when it's stuck in centralized databases.

> And not to mention all of the PII that’s core to DMV’s operations that can’t be public, so it can’t be on a public blockchain anyway.

Nobody said literally everything the DMV does should be on a blockchain.

In this context of "CarFax but better", very little (if any) of that PII needs to be present in the ledger - and certainly not in plaintext. The core datum here is the VIN, and that's already far from private.

[Zanfa]

> I'm more referring to it in the sense of "I trust you to competently administer this database and not tamper with its data"

A well-administered non-tamperable database of garbage data is still quite useless.

With an unpermissioned public blockchain you can make up your own police department, insurance, towing company and repair shops. Make some wash entries to make them look legitimate and you’re back to square one of having to confirm everything off-chain to figure out what’s real.

Or drown a real report in a sea of fakes if you’re trying to offload a lemon, since there’s not much you can do about spam.

Not to mention the fundamental problems around private key management.

[hot_gril]

I don't trust the DMV. It's not that I think they're out to get me, it's that some crappy system on their end always screws something up and locks me out of whatever it is I need.