Hacker News Reader

Comment by canterburry | Hacker News Reader

We pretty much use a private blockchain for the very same purpose.

Its internal, only our systems have access, each user/customer is auto created an account on signup, we hold the private keys encrypted with the user's password so we can't access the key itself, keeps track of everything with 100% consistency.

1s block mining and raft consensus settings so pretty much instant and low resource utilization...and massively scalable.

Sorry to say but if I am in any type of fintech, I would never ever outsource keeping track of my customer's account balances and source of truth.

View on HN

If you're using a private blockchain where only your systems have access, why not use postgres with restricted user permissions?

I can't answer for OP as I don't know his/her situation, but every time I have asked this question to other companies, the answer boils down to

"We really wanted to use a blockchain and it is the main reason why we build the company in the first place so we never questioned that choice".

Am not the parent but, for example, the Bitcoin blockchain is essentially a double-entry transaction ledger. Every transaction has to balance inputs and outputs.

If the product poster is using has that property, then perhaps is a reasonable choice.

Postgres does not have any ledger balancing primitives.

For Decimals I’m using a hash-chain. So, entries are always balanced, atomic and immutable. Not a blockchain, as there is no need for consensus, but the properties for checking integrity are all in there.

Bitcoin-like blockchains are by default triple-entry accounting: https://onlinelibrary.wiley.com/doi/abs/10.1111/acfi.12556

Completely understand. This is a normal concern for new technology, not every company is an early adopter.

The same way Lyft would not even consider using Stripe in its first two years, considering how critical credit card data is for them.

I really like the design you have internally! I would love to hear more about it, can we talk?

Curious, why is card data important to Lyft? How does card data benefit a transportation business in any way beyond just taking money from the cards?

If they sent the card data from their customers to a 3 person startup it could be stolen and make their customers unhappy.

This was likely just as much about credit card fees as it is about data.

Stripe's amazing service also comes at a substantial premium. For a high-volume thin-margin company like Lyft where every penny counts, per transaction fees at 2.9%+ are killers. Furthermore, large companies prefer to own the raw card data themselves as the interchange rates for card not present debit cards is different than card not present credit cards. Once you hit a certain amount of scale this .15% difference is substantial.

(edit: I missed that parent comment was about trust in a 3-person startup, but point is still somewhat valid)

Companies at even a hundredth of Lyft's scale aren't paying 2.9%+ to Stripe, they're on cost-plus pricing based on interchange fees.

Hey Canterbury, very intrigues with the idea of using a private blockchain for this purpose. I building exactly that as a service. Could we have a quick chat about what issues you had and the process?

I may be misunderstanding but what happens when your customer changes their password?

Ideally the login password hash and the account for record keeping's password would be decoupled

Reply on news.ycombinator.com