Is 1 Confirmation enough to prevent double spend?

buwaytress

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Quote from: puremage111 on July 21, 2017, 04:10:28 AM

As the blockchain growth time by time, which means the difficulty tend to become harder and harder.

Previously i've seen most casino only credits payment after 2 confirmation

Recently i've deposit into several site like casino, purchasing site. And most of it uses 0-1 Confirmation.

Therefore come to our main question, in the current state, is 1 confirmation enough to protect and prevent double spend?

1. There are plenty of 1 and even 0 confirmation casinos, but they protect themselves anyway by requiring all deposits to have more confirmations when you request a withdraw.
2. Technically, no amount of confirmations can prevent double spends, but the likelihood of a double spend attempt becomes lower and lower with each additional confirmation. This likelihood becomes impractical to even attempt some time after 6 confirmations, if I remember, but for most cases, 1 confirmation is "safe enough" for insignificant amounts.

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Quote from: Syke on July 21, 2017, 05:21:44 PM

You need to assign a probability to the question. 1 confirmation is not a 100% absolute guarantee that a double spend won't happen.

... and transferred amount either matter Grin

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Quote from: puremage111 on July 21, 2017, 04:10:28 AM

Therefore come to our main question, in the current state, is 1 confirmation enough to protect and prevent double spend?

You need to assign a probability to the question. 1 confirmation is not a 100% absolute guarantee that a double spend won't happen.

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Quote from: puremage111 on July 21, 2017, 04:10:28 AM

As the blockchain growth time by time, which means the difficulty tend to become harder and harder.

Previously i've seen most casino only credits payment after 2 confirmation

Recently i've deposit into several site like casino, purchasing site. And most of it uses 0-1 Confirmation.

Therefore come to our main question, in the current state, is 1 confirmation enough to protect and prevent double spend?

The real question should be is double-spend a threat to Bitcoin becoming mainstream? The answer is no. It takes tons of hashing power after a few confirmations, or even one for that matter... which makes this a moot point.

ranochigo

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Quote from: amaclin1 on July 21, 2017, 10:16:03 AM

Quote from: ranochigo on July 21, 2017, 10:11:44 AM

they cannot orphan blocks before that checkpoint.

they can

How so? If my client have a checkpoint at X, how could they still orphan blocks before that?
Edit: Don't get me wrong, I'm open to the fact that I may be wrong but I can't seem to find a good explanation on it.

amaclin1

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Quote from: ranochigo on July 21, 2017, 10:11:44 AM

they cannot orphan blocks before that checkpoint.

they can

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Quote from: puremage111 on July 21, 2017, 10:06:08 AM

Ouh it doesn't? I see, i always thought that blockchain size does affect on the difficulty xd So amount of miners do affect it?

Network hashrate is the main factor that affects the frequency of the block and hence the difficulty.

Quote from: puremage111 on July 21, 2017, 04:10:28 AM

For this point : Transaction is made after the checkpoint, is there something called as 0 confirmation? Is checkpoint mark when a coin sending command is execute or it only starts to check once 1 confirmation is done?

Thanks

They are already included in the Blockchain when they are mined by a miner.

Checkpoints are hardcoded into clients and since double spending requires the miner to use their hashpower to rewrite the Blockchain, they cannot orphan blocks before that checkpoint. If you have transactions included before then, your transaction is pretty much irreversible unless the network changes their client's checkpoint.

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Quote from: puremage111 on July 21, 2017, 04:10:28 AM

Therefore come to our main question, in the current state, is 1 confirmation enough to protect and prevent double spend?

To create a double spend on a transaction that as already 1 confirmation, you would need to have a non-trivial amount of hashpower to actively attack the network. So yes, for most use cases 1 confirmation is enough.

For more details, check these links out:

https://en.bitcoin.it/wiki/Confirmation

https://people.xiph.org/~greg/attack_success.html

puremage111

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Quote from: ranochigo on July 21, 2017, 05:07:46 AM

The blockchain size really has absolutely nothing to do with the difficulty.

Ouh it doesn't? I see, i always thought that blockchain size does affect on the difficulty xd So amount of miners do affect it?

Quote from: puremage111 on July 21, 2017, 04:10:28 AM

Previously i've seen most casino only credits payment after 2 confirmation

Recently i've deposit into several site like casino, purchasing site. And most of it uses 0-1 Confirmation.

Therefore come to our main question, in the current state, is 1 confirmation enough to protect and prevent double spend?

Quote

This does have something to do with difficulty. As the difficulty increases, it becomes harder to mine a block and will need a lot of hashpower to even get a block. In most of the attacks an user can execute, loads of hashpower is needed and it becomes unfeasible to double spend a transaction.

Most of the casinos allows for 1 confirmation deposit since a long time ago.

Just a small correction: It is impossible to prevent a double spend if the transaction is made after the checkpoint. The risk is insignificant if its for daily purchases with the assumption that the attackers are looking for profit.

For this point : Transaction is made after the checkpoint, is there something called as 0 confirmation? Is checkpoint mark when a coin sending command is execute or it only starts to check once 1 confirmation is done?

Thanks

amaclin1

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Quote from: ranochigo on July 21, 2017, 05:07:46 AM

Most of the casinos allows for 1 confirmation deposit since a long time ago.

This is not an answer to the question Grin

In fact the question is incorrect itself.
Is one umbrella enough protection against a meteorite?

ranochigo

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Quote from: puremage111 on July 21, 2017, 04:10:28 AM

As the blockchain growth time by time, which means the difficulty tend to become harder and harder.

The blockchain size really has absolutely nothing to do with the difficulty.

Quote from: puremage111 on July 21, 2017, 04:10:28 AM

Previously i've seen most casino only credits payment after 2 confirmation

Recently i've deposit into several site like casino, purchasing site. And most of it uses 0-1 Confirmation.

Therefore come to our main question, in the current state, is 1 confirmation enough to protect and prevent double spend?

This does have something to do with difficulty. As the difficulty increases, it becomes harder to mine a block and will need a lot of hashpower to even get a block. In most of the attacks an user can execute, loads of hashpower is needed and it becomes unfeasible to double spend a transaction.

Most of the casinos allows for 1 confirmation deposit since a long time ago.

Just a small correction: It is impossible to prevent a double spend if the transaction is made after the checkpoint. The risk is insignificant if its for daily purchases with the assumption that the attackers are looking for profit.

puremage111

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As the blockchain growth time by time, which means the difficulty tend to become harder and harder.

Previously i've seen most casino only credits payment after 2 confirmation

Recently i've deposit into several site like casino, purchasing site. And most of it uses 0-1 Confirmation.

Therefore come to our main question, in the current state, is 1 confirmation enough to protect and prevent double spend?

Topic: Is 1 Confirmation enough to prevent double spend? (Read 976 times)