The math behind confirmations?

[BlackHatCoiner]

For all intents and practical purposes up to around 100 BTC or equivalent fiat value, 1 confirmation is good enough.

That's, currently, equivalent to 3 million dollars. If the person you're dealing with, again anonymously and with other necessary conditions so you can't reach him legally, is a miner he's really incentivized to reverse it and gets his 100 BTC back. He could cooperate with a mining pool, which will increase his chances; he may even is a pool.

I'd say that 6 confirmations for anything above a million dollars is a number to sleep easy with.

[1714952617]

1714952617

[1714952617]

1714952617

[1714952617]

1714952617

[n0nce]

For all intents and practical purposes up to around 100 BTC or equivalent fiat value, 1 confirmation is good enough.

That's, currently, equivalent to 3 million dollars. If the person you're dealing with, again anonymously and with other necessary conditions so you can't reach him legally, is a miner he's really incentivized to reverse it and gets his 100 BTC back. He could cooperate with a mining pool, which will increase his chances; he may even is a pool.

I don't think it's worth it for 3 million dollars. I'm not sure about exact numbers in terms of electricity, but renting enough pools to have a good shot at reversing a transaction that is 1 block deep, for just 10 minutes, might actually be more expensive than 3 million dollars, not to speak of 'bribing fees' - after all, it's a big ask to get a mining pool to actually perform an attack. It could give a huge dink to their reputation if someone figures it out.

[Dabs]

Maybe modify it to something like:

$1 million = 1 confirmation.
$10 million = 2 confirmations.

If you sent it, you know you're good. If the other person sent it, you can quickly check within 10 seconds to see if there are any attempted double spends as well as to check if a proper minimum transaction fee was used. Also, you have to have some level of trust with the other person anyway for your transaction with them.

Are you selling a car? Are you trading for a house? Or is it just some baby toy or gaming console / robucks / gift card? The house isn't going anywhere, and the lambo probably has GPS on it.

If you are accepting 100 BTC to trade for something physical, then there is that simple act of sending the item or meeting them in person and a 10 minute wait for 1 block is more than enough.

If you are accepting 100 BTC to trade for something not tangible, then ... maybe they can wait a few more minutes after 1 confirmation, or they may be willing to accept that you will wait for 2. Some things might take longer to send than the BTC you are receiving anyway.

There are good incentives on both sides of the transaction to perform an honest trade, even if the other guy is a miner with more than 51% of the hash power, which is very unlikely. They would just do better to mine like any normal miner and get the usual block reward.