Why 6 comfirmation?

[Floxynice]

Just need clarity, can big players like Foundry USA actually alter transactions on the blockchain? Is this really possible?

Foundry USA or any other mining pool can try to remove a block from the blockchain and they will be able to do so, if they are lucky enough.
Take note that even if they manage to remove a block, that doesn't mean they can steal the fund you sent to someone. Your transaction will be included in another block.

Is there any chance any of mining pools try to do so?
That's very unlikely. They won't do something that can damage their reputation. Also, it's very expensive to perform such an attack and it's more profitable to be a honest miner.

Okay, this makes sense to me now. I don't think a large mining pool would want to tarnish their reputation as the chances of succeeding with the attack is still very slim.

The blockchain is a system of verification not trust.

Oh! Got this one now. Thanks for the correction.

[Synchronice]

Just need clarity, can big players like Foundry USA actually alter transactions on the blockchain? Is this really possible?

Foundry USA or any other mining pool can try to remove a block from the blockchain and they will be able to do so, if they are lucky enough.
Take note that even if they manage to remove a block, that doesn't mean they can steal the fund you sent to someone. Your transaction will be included in another block.

Is there any chance any of mining pools try to do so?
That's very unlikely. They won't do something that can damage their reputation. Also, it's very expensive to perform such an attack and it's more profitable to be a honest miner.

So, If I understood correctly, Foundry USA can remove block that they mined. There might be a case when they mine two blocks in a row and they'll be able to remove both blocks from the blockchain, right? So, technically, 6 confirmation means that there is a very low chance that any miner or pool will mine 6 blocks in a row and that's why 6 confirmation is considered to be a safe choice. Am I right here? If this is the case, then should Bitcoin have beeen made in a way that it will 100% prevent one miner/pool to mine, discover 6 blocks in a row? For better security?
I agree with you that it would be very stupid if any mining pool, especially large one decides to perform such an attack.

[hosseinimr93]

So, If I understood correctly, Foundry USA can remove block that they mined. There might be a case when they mine two blocks in a row and they'll be able to remove both blocks from the blockchain, right?

No, you didn't understand it correctly. It doesn't matter who has mined the block and it's not that a mining pool can remove the blocks mined by themselves.

Keep in mind that the winning chain is always the one that has the most work. To remove a block from the blockchain, the dishonest mining pool have to create a new chain that doesn't have that block and has the most work.
Read my previous post, please.

[Pmalek]

I remember that years ago it was 6 confirmations and then slowly people started to accept 3 confirmations and then some businesses, mostly casinos risked accepting transactions with 1 confirmation. I personally think that 3 confirmations is enough and 6 only delays the access to funds.

Crypto casinos can afford that luxury because they are in total control of the coins on their platform and you are just gambling with digits on a screen. Some casinos accept 0-confirmation transactions. You can play as soon as their system recognized the receiving transaction. It doesn't need to be confirmed. But if you get lucky and win, your deposit transaction has to confirm before you can withdraw your winnings. They can't lose their own money by accepting unconfirmed transactions. Only the players can lose.

[_BlackStar]

-snip-

Crypto casinos can afford that luxury because they are in total control of the coins on their platform and you are just gambling with digits on a screen. Some casinos accept 0-confirmation transactions. You can play as soon as their system recognized the receiving transaction. It doesn't need to be confirmed. But if you get lucky and win, your deposit transaction has to confirm before you can withdraw your winnings. They can't lose their own money by accepting unconfirmed transactions. Only the players can lose.

Honestly - I've heard of casinos that operate their service like that, but forget what the name of the casino is. Of course - when a casino or certain service has allowed its customers to see the balance in the wallet before the transaction is confirmed, then they have prepared terms and conditions before the customer withdraw their money. Casinos don't want to lose - every feature should benefit them from a business perspective.