you are only sure when blockchain.info site doesn't show the number of confirmations(I think after 100 confirmations)
But every confirmation makes more and more unlikely some kind of doublespend. At the point of being in practice impossible. After 3 I think the risk is 0 no matter the value.
I'm still to know about some doublespend of a transactions that got 2 or more confirmations.
Topic: How many confirmations to be sure about a transaction? (Read 3620 times)
OP, please close this topic. The question has been answered and all new answer are just copies of the others.
Hi,
1 confirmation for low risk or low btc amount
6 confirmation for high risk high btc amount
Thanks
1 confirmation for low risk or low btc amount
6 confirmation for high risk high btc amount
Thanks
Hi,
1 confirmation for low risk or low btc amount
6 confirmation for high risk high btc amount
Thanks
1 confirmation for low risk or low btc amount
6 confirmation for high risk high btc amount
Thanks
This is a great list 
I bookmarked your post. One question remains. Why 0 confirmations? Wouldn't it be completely risky not waiting until it achieved at least one confirmation?
Nope. In fact, I feel that 0 confirmation is safe for less than $500 as long as it fits a few criteria. I bookmarked your post. One question remains. Why 0 confirmations? Wouldn't it be completely risky not waiting until it achieved at least one confirmation?I think of it like this...
0 confirmations = fast food purchase
3 confirmations = expensive dinner
6 confirmations = cool dirt bike
10 confirmations = 40 acre farm
0 confirmations = fast food purchase
3 confirmations = expensive dinner
6 confirmations = cool dirt bike
10 confirmations = 40 acre farm
1. Inputs must not be unconfirmed
2. Transaction has a reasonable fee/kb
3. There isn't any competing transactions
4. The mining pools and nodes at geographically distributed areas have seen it.
Most mining pools do not accept transactions with spent inputs and would include whichever transaction appeared first. Also, majority of network has Bitcoin Core as their client. They relay which ever transaction came first and would ignore any other transactions with spent input in their mempool. Of course, you can ask a miner to mine the double spend for you but it isn't worth it for less than $500.
maybe 5/6
i'm not sure about it technically but most sites require at least 1 confirmation to use the site and withdraw, some require 3-6 confirmations.
This is a great list I bookmarked your post. One question remains. Why 0 confirmations? Wouldn't it be completely risky not waiting until it achieved at least one confirmation?
I bookmarked your post. One question remains. Why 0 confirmations? Wouldn't it be completely risky not waiting until it achieved at least one confirmation?I think of it like this...
0 confirmations = fast food purchase
3 confirmations = expensive dinner
6 confirmations = cool dirt bike
10 confirmations = 40 acre farm
0 confirmations = fast food purchase
3 confirmations = expensive dinner
6 confirmations = cool dirt bike
10 confirmations = 40 acre farm
6 to be absolutely 100% safe.
I agree. for a lesser value transaction a single confirmation has been safe enough. But like its been said for high value transaction, just to be satisfied regarding the risk of reversing, it is better to go for at least five confirmations.Yes its not really a risk if its like buying a coffee at the starbuck. And one transaction when you are buying something on the internet should not be a big bother if its something like an full priced AAA game.
And the confirmations that "we" recommend to wait before releasing whatever products is not really about the 51% attack. Its more in case we get a rollback because a split or a bug occurred. Some transactions can disappear when that happen, it did in the past, no idea if it will happen again.
Well, the most serious one was with the fork in 2013. The less serious one was with BIP66 but it wasn't a threat unless you use a SPV client. And yeah, you need 30+ confirmations for it to be safe when using SPV client at that time.
6 to be absolutely 100% safe.
I agree. for a lesser value transaction a single confirmation has been safe enough. But like its been said for high value transaction, just to be satisfied regarding the risk of reversing, it is better to go for at least five confirmations.Yes its not really a risk if its like buying a coffee at the starbuck. And one transaction when you are buying something on the internet should not be a big bother if its something like an full priced AAA game.
And the confirmations that "we" recommend to wait before releasing whatever products is not really about the 51% attack. Its more in case we get a rollback because a split or a bug occurred. Some transactions can disappear when that happen, it did in the past, no idea if it will happen again.
6 to be absolutely 100% safe.
I agree. for a lesser value transaction a single confirmation has been safe enough. But like its been said for high value transaction, just to be satisfied regarding the risk of reversing, it is better to go for at least five confirmations.6 to be absolutely 100% safe.
I agree. for a lesser value transaction a single confirmation has been safe enough. But like its been said for high value transaction, just to be satisfied regarding the risk of reversing, it is better to go for at least five confirmations.
Thanks for all the answers. Now I have got a good picture of how many confirmations my transactions need in order to be save.
i would say at least 2 confirmations. But better is to wait until you have 5 confirmations for small amounts. For larger amounts you should wait until at least 20 confirmations.
something between one and six. If in doubt, wait for three confirmations. that's what I would recommend
I have seen alot of people wait between 3-5 transactions so I use that as a rule of thumb for my own transactions.
i think 6 confirmations is enough to get sure about transactions that is 1BTC+.
On other hand 3 confirmations is enough for lower amount of BTCs.
On other hand 3 confirmations is enough for lower amount of BTCs.
Yes these are the best way of getting your bitcoin transaction most securely. But 6confirmation or 3 confirmations are best suited only with latest bitcoin core client only. If you use old bitcoin-qt client then you must wait for some 30 confirmations.
When pools are SPV mining, they don't check the validity of the block and whether it complies with the network. Those mining pools then generate invalid blocks which get invalidated by Bitcoin core 0.10+ but not anything below or on 0.9.4 or earlier as those Core clients are not aware of the new rules. AFAIK, this isn't a threat right now. Majority of pools are mining on correct rules and creating valid blocks.
Which also mean it does not mean if some wallets are outdated and accept some invalid blocks, the network itself will reject it, because most hashrate is pointed at the right wallet version.
Still too bad but not a threat.
A miner generated a block that doesn't follow the rule and miners that verify the blocks do not consider it as valid but those who have SPV mining on will continue mining on that chain and SPV client will follow the longest chain and accept it as valid. This was a threat for merchants accepting 1 confirmation transactions but there wasn't any attack at that time.
i think 6 confirmations is enough to get sure about transactions that is 1BTC+.
On other hand 3 confirmations is enough for lower amount of BTCs.
On other hand 3 confirmations is enough for lower amount of BTCs.
Yes these are the best way of getting your bitcoin transaction most securely. But 6confirmation or 3 confirmations are best suited only with latest bitcoin core client only. If you use old bitcoin-qt client then you must wait for some 30 confirmations.
When pools are SPV mining, they don't check the validity of the block and whether it complies with the network. Those mining pools then generate invalid blocks which get invalidated by Bitcoin core 0.10+ but not anything below or on 0.9.4 or earlier as those Core clients are not aware of the new rules. AFAIK, this isn't a threat right now. Majority of pools are mining on correct rules and creating valid blocks.
Which also mean it does not mean if some wallets are outdated and accept some invalid blocks, the network itself will reject it, because most hashrate is pointed at the right wallet version.
Still too bad but not a threat.
A miner generated a block that doesn't follow the rule and miners that verify the blocks do not consider it as valid but those who have SPV mining on will continue mining on that chain and SPV client will follow the longest chain and accept it as valid. This was a threat for merchants accepting 1 confirmation transactions but there wasn't any attack at that time.
Usually 1 is enough but in the case of confirmations, the more the better!
i think 6 confirmations is enough to get sure about transactions that is 1BTC+.
On other hand 3 confirmations is enough for lower amount of BTCs.
On other hand 3 confirmations is enough for lower amount of BTCs.
Yes these are the best way of getting your bitcoin transaction most securely. But 6confirmation or 3 confirmations are best suited only with latest bitcoin core client only. If you use old bitcoin-qt client then you must wait for some 30 confirmations.
When pools are SPV mining, they don't check the validity of the block and whether it complies with the network. Those mining pools then generate invalid blocks which get invalidated by Bitcoin core 0.10+ but not anything below or on 0.9.4 or earlier as those Core clients are not aware of the new rules. AFAIK, this isn't a threat right now. Majority of pools are mining on correct rules and creating valid blocks.
Which also mean it does not mean if some wallets are outdated and accept some invalid blocks, the network itself will reject it, because most hashrate is pointed at the right wallet version.
Still too bad but not a threat.
I think of it like this...
0 confirmations = fast food purchase
3 confirmations = expensive dinner
6 confirmations = cool dirt bike
10 confirmations = 40 acre farm
0 confirmations = fast food purchase
3 confirmations = expensive dinner
6 confirmations = cool dirt bike
10 confirmations = 40 acre farm
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