[deebosong]

I am a laymen who is skeptical of cryptocurrency tech, mostly because of what I'm seeing (hype, greed, fomo, and apparently no real use-cases).

If... crypto were to be able to reverse transactions... would that completely undermine the whole point of it and make it look absolutely stupid?

Do you think the solution to irreversible transactions would be to then have some kind of algo that would then send back a mistaken transaction after getting checked by some intermediary checkpoint? Would that then make the whole point of cryptocurrency also completely pointless?

What on earth are people dumping resources into all this as digital currency or even investment/ speculation vehicles if they don't address the irreversible transaction part, or try to compensate for it somehow? It seems utterly anxiety inducing otherwise, where you'd have to quadruple check, then quadruple check again, and then sleep on it and then quadruple check 4 more times before you do any kind of sizable transaction.

[tromp]

> It seems utterly anxiety inducing otherwise, where you'd have to quadruple check, then quadruple check again, and then sleep on it and then quadruple check 4 more times before you do any kind of sizable transaction.

That's mostly due to transactions being non-interactive. If the receiver has to prove their ability to spend the received funds before being allowed to receive them, then most of this anxiety disappears. Certain blockchain designs require transactions to be interactive in this way.

[tsimionescu]

> If the receiver has to prove their ability to spend the received funds before being allowed to receive them

If I want to send you some crypto money in exchange for you mowing my lawn, how do you prove that you can spend the received funds? And if I accidentally send it twice, why would I care that you can spend them twice, unless I have some way to compel you to send half back?

[tromp]

> how do you prove that you can spend the received funds?

You prove it by producing a partial signature for the transaction (a transaction essentially requires a multisig by both sender and receiver).

> And if I accidentally send it twice

You couldn't send it twice because the transaction consumes an input utxo. Paying twice would require two different transactions with two different multisignatures.

[tsimionescu]

> You prove it by producing a partial signature for the transaction (a transaction essentially requires a multisig by both sender and receiver).

Oh, ok, I misunderstood what this meant.

> You couldn't send it twice because the transaction consumes an input utxo. Paying twice would require two different transactions with two different multisignatures.

This assumes the receiver is trust-worthy, that they counter-sign the transaction if it was accidental. So if I accidentally pay twice for a single item, the seller can just sign both transactions and send me only one item, and I can't do much about it. Of course, they can also send 0 items, which is why blockchains can't secure transactions in a useful sense - you need the law and insurance and other social mechanisms for that.