Insu Dra



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Full MemberActivity: 182Merit: 100 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 13, 2013, 09:58:08 AM #21 So we can conclude the 10-60 min for a 100% secure conformation is extremely fast compared to (none crypto) competition. And that adding extra bloat to block chain and network is simply not worth it ... (not cost effective at all)



It makes me wonder how the 2 min blocks affect max transaction per second as well ... I'm relatively sure faster blocks reduces the max amount of transactions per second but would need to do math to confirm that ... to lazy today. "drugs, guns, and gambling for anyone and everyone!"

Prophet



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NewbieActivity: 36Merit: 0 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 13, 2013, 01:54:25 PM #22 The network is ultra secure. but we can definitely shave off some time down to 2 minutes would be way faster.



It would actually quintuple transaction maximum from 400k transactions per day to 400k max every 4 1/2 hours so we would have a daily transaction maximum of 2 million.



now if we consider that we will be cutting off modem users from the network and also people with slow connections it will cause an evolutionary pressure to upgrade, bonus. having that extra time for them does make it hard to overcome the network with a lightning fast propagation time but... if everyone has a gigabit connection then we would be increasing the confirmation security over the same 10 minute time period. the same hashing power in a smaller block time frame, statistical increase in security by the number of confirmations, the greater amount of hashing power will overcome anyone even with only 2 minutes of slack with a 25mbit connection.



and yes the authorization can be done instantaneously for paying for coffees and stuff, and it also makes it hard to do a low cost(sub $10) double spend attack within two minutes, those fast food places better have small lines.

Garrett Burgwardt



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Sr. MemberActivity: 476Merit: 251 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 14, 2013, 12:52:41 AM #26 Quote from: MWNinja on June 13, 2013, 06:37:42 PM If we don't do something like this we are effectively throwing away all of the additional compute power added by ASIC adoption.



I don't see any evidence that this is the case.



As far as a faster confirmation, it seems that we're so far at least in agreement that very fast (<1 minute) blocks aren't ideal. I'd say that there's definitely an argument for 5 minute confirmations.



Now, of course there's no additional security for n>6 transactions (if we're going to assume that 3 10 minute confirmations protect sufficiently from double spends). But incremental security is provided at low numbers of confirmations, for example, 1 5 minute confirmation is infinitely more secure than 0 confirmations under either timeframe. At 2 5 minute confs & 1 10 minute confirmation, security is the same and total block size is slightly increased (block headers). 3 5 minute confirmations is 1.5x as secure as 1 10 minute confirmation, and so on.



This certainly isn't a critical need to change the confirmation time, but cutting the confirmation time in half could be argued to be worth the effort.



My thoughts, anyway. I don't see any evidence that this is the case.As far as a faster confirmation, it seems that we're so far at least in agreement that very fast (<1 minute) blocks aren't ideal. I'd say that there's definitely an argument for 5 minute confirmations.Now, of course there's no additional security for n>6 transactions (if we're going to assume that 3 10 minute confirmations protect sufficiently from double spends). But incremental security is provided at low numbers of confirmations, for example, 1 5 minute confirmation is infinitely more secure than 0 confirmations under either timeframe. At 2 5 minute confs & 1 10 minute confirmation, security is the same and total block size is slightly increased (block headers). 3 5 minute confirmations is 1.5x as secure as 1 10 minute confirmation, and so on.This certainly isn't a critical need to change the confirmation time, but cutting the confirmation time in half could be argued to be worth the effort.My thoughts, anyway.

Eri



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Sr. MemberActivity: 264Merit: 250 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 14, 2013, 12:58:13 AM #27 its already been explained why faster blocks dont increase security. if the blocks come every 2 minutes then they are 4/5ths easier to make. that means 1/5th as secure. So rather then 6 confirmations youd need 30 to have the same security. Plus orphaned blocks would go up as a result. They would be 5 times more likely to happen. 10 minutes was chosen for a reason. It doesnt need to be smaller, its serves no purpose.



-future-

When the block size increases to allow more transaction, were going to need that larger 10 minute block time to help reduce orphaned blocks. On my home connection i can move 1MB in a second, even if the blocks were 10MB it still wouldnt be an issue, it would merely take 10 seconds to move. I think its also fairly obvious that as time goes on people with dialup would be pushed out of the block generating business if anyone even uses dialup for this to begin with. By the time we end up with blocks at 10MB, were going to have pruning and at that point block size wont matter much. because all 'used' transactions will be removed anyway. We could even implement a torrent like behavior to help spread blocks across the network faster.



All in all, bitcoins future is bright and people worry over nothing.

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LegendaryActivity: 1176Merit: 1018 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 14, 2013, 02:21:09 AM #28 Quote from: Eri on June 14, 2013, 12:58:13 AM its already been explained why faster blocks dont increase security. if the blocks come every 2 minutes then they are 4/5ths easier to make. that means 1/5th as secure. So rather then 6 confirmations youd need 30 to have the same security. Plus orphaned blocks would go up as a result. They would be 5 times more likely to happen. 10 minutes was chosen for a reason. It doesnt need to be smaller, its serves no purpose.



I'm not sure I agree. Wouldn't it be harder for an attacker to issue 5 2-minute blocks in a row than it would be for them to generate a single 10 minute one? I can see it being easier to make 5 2-minute blocks in a row than 5 10-minute ones, but I think what matters is expected security after x amount of time. After 30 minutes (approx. 15 blocks) with 2-min blocks you would be safer than 30 minutes with 10-minute blocks.



Its like a serial dilution when you are rinsing something. Given a soapy jug and a one jug full of rinse water, if you just poured the rinse water into the soapy jug and then dumped it out there would be plenty of soap residue left (this being the 10 minute block). If you take the rinse water and add a pint at a time to the soapy jug, slosh it around, and dump it out, and then repeat that 8 times, the soapy jug will be very, very clean (this being the 1.125 minute block). The water is like our hashing power. There are more and less efficient ways to use its properties for our ends.

I'm not sure I agree. Wouldn't it be harder for an attacker to issue 5 2-minute blocks in a row than it would be for them to generate a single 10 minute one? I can see it being easier to make 5 2-minute blocks in a row than 5 10-minute ones, but I think what matters is expected security after x amount of time. After 30 minutes (approx. 15 blocks) with 2-min blocks you would be safer than 30 minutes with 10-minute blocks.Its like a serial dilution when you are rinsing something. Given a soapy jug and a one jug full of rinse water, if you just poured the rinse water into the soapy jug and then dumped it out there would be plenty of soap residue left (this being the 10 minute block). If you take the rinse water and add a pint at a time to the soapy jug, slosh it around, and dump it out, and then repeat that 8 times, the soapy jug will be very, very clean (this being the 1.125 minute block). The water is like our hashing power. There are more and less efficient ways to use its properties for our ends.

amincd



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Hero MemberActivity: 772Merit: 500 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 14, 2013, 04:55:22 AM

Last edit: June 14, 2013, 04:06:43 PM by amincd #29



I'll collate my responses to common objections to a shorter block time:



Quote Faster blocks mean less security. You need 10 one-minute blocks to have as much security as one 10-minute block

This is not true. The probability of solving a block will always be the same for a given hashrate, regardless of the block time.



While some security is established by the amount of time required to get a confirmation, by increasing the cost to an attacker who is renting hardware to launch an attack, an attacker with a given hashrate* will have a much higher probability of double spending a 1-confirmation transaction in a 10 minute block-time chain than a 10-confirmation transaction in a 1 minute block-time chain. Meni Rosenfeld showed the math for this:



The trade-off is that with a higher rate of block generation, latency wastes more work, leading to lower difficulty for a >50% attack. For a POW network with a 135.03 TH/s hashrate like Bitcoin, the 10% decline in the difficulty of pulling off a >50% attack that would be caused by a change to a one-minute block time is probably tolerable, and worth the gain in more quickly secured transactions.



*as long as it's not close to 50% of the network hashrate



Quote A one or two minute block time is still too slow for point of sale, so there's no point in adopting it.

It's not enough for PoS, but in certain scenarios it would still be useful, like depositing BTC at an exchange or e-wallet that requires 1 confirmation to guard against corrupt miners which will permit 0-confirmation tx replacement for a fee.



It leads to a transaction more quickly reaching the network's maximum level of confirmation security, at the cost, as mentioned, of decreasing the difficulty of a >50% attack.



Quote Changing the block time would violate what Bitcoin is supposed to be. What are we going to change next, the number of bitcoins issued per block?

According to the bitcoin wiki, the prohibited changes to bitcoin's protocol are:



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



Increasing the total number of issued bitcoins beyond 21 million. Precision may be increased, but proportions must be unchanged.

Changing the bitcoin distribution algorithm such that the subsidy at any given time period is decreased without miner consensus and 3 years notice, or increased beyond improved precision of halving (lossy beginning with block 1,890,000).

Any rule that adds required, explicit centralization. For example, a change requiring that all blocks be signed by some central organization.



A technical improvement that doesn't change the 21 million coin limit and helps bitcoin better meet its initial design goal of being a "purely peer-to-peer version of electronic cash" which "would allow online payments to be sent directly from one party to another without going through a financial institution" does not change what makes bitcoin important and valuable. I think a shorter block time would definitely be a little helpful to Bitcoin and I think we should target a 1 minute block time rather than 2 minutes.I'll collate my responses to common objections to a shorter block time:This is not true. The probability of solving a block will always be the same for a given hashrate, regardless of the block time.While some security is established by the amount of time required to get a confirmation, by increasing the cost to an attacker who is renting hardware to launch an attack, an attacker with a given hashrate* will have a much higher probability of double spending a 1-confirmation transaction in a 10 minute block-time chain than a 10-confirmation transaction in a 1 minute block-time chain. Meni Rosenfeld showed the math for this: https://bitcoil.co.il/Doublespend.pdf The trade-off is that with a higher rate of block generation, latency wastes more work, leading to lower difficulty for a >50% attack. For a POW network with a 135.03 TH/s hashrate like Bitcoin, the 10% decline in the difficulty of pulling off a >50% attack that would be caused by a change to a one-minute block time is probably tolerable, and worth the gain in more quickly secured transactions.*as long as it's not close to 50% of the network hashrateIt's not enough for PoS, but in certain scenarios it would still be useful, like depositing BTC at an exchange or e-wallet that requires 1 confirmation to guard against corrupt miners which will permit 0-confirmation tx replacement for a fee.It leads to a transaction more quickly reaching the network's maximum level of confirmation security, at the cost, as mentioned, of decreasing the difficulty of a >50% attack.According to the bitcoin wiki, the prohibited changes to bitcoin's protocol are:A technical improvement that doesn't change the 21 million coin limit and helps bitcoin better meet its initial design goal of being a "purely peer-to-peer version of electronic cash" which "would allow online payments to be sent directly from one party to another without going through a financial institution" does not change what makes bitcoin important and valuable.

Eri



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Sr. MemberActivity: 264Merit: 250 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 14, 2013, 02:15:47 PM #31 If you pre mine a block and have it waiting until you buy something to release it to unspand the transaction, then yes a shorter block time would help in the sense the attacker would have less time to act. but in either case your talking about small amounts of money risking a large block reward if someone else finds the next block first. with the increase in orphaned blocks i really dont think its worth it.



an attacker could try to cheat the system of a small purchase, but it would be at the risk of losing the block reward that mining the block would give them.



just to throw some numbers out there. if you found a block and held it for an attack youd be risking 3250$(BTC25 x $130)

to try to undo a transaction you just made, for anything under that dollar amount its simply not worth the attempt. for anything over, it will certainly require at least one confirmation. Not to mention, who would go into a store and attempt that transaction risking being arrested for fraud or theft. the number would have to be allot larger, ie if the transaction was the exact same value as the block reward then they have no incentive to try the attack, if the transaction was 2 times the size of the block reward they would have a 3250$ incentive to try it, and to risk jail. Again though, At that value who wouldnt require at least 1 confirmation?



This is why i really dont see it as a threat. i classify it as a non issue.

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Sr. MemberActivity: 266Merit: 250aka 7Strykes Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 14, 2013, 02:18:03 PM #32 Quote from: Prophet on June 14, 2013, 01:39:46 PM Remember what has been going on with feathercoin for the past while, they've been attacked by a 51% attack, it forked their client and started orphaning everyone elses transactions.





What are the examples from other Cryptocurrencies do we have to observe real world effects?



You also seem to misunderstand that the Bitcoin network is HUNDREDS of times faster than the feathercoin network. I could fork any of these brand new altcoins if I jump on first.



Also, I don't think the shorter block time would be much of an issue anyways. I may not understand false transactions and double spends entirely, but wouldn't faster blocks make it HARDER for someone to double spend? The following statement is made with the assumption that the attacker does not have 51% of hashpower. If someone wanted to double spend, wouldnt they need to attack each and every block until the confirmations accepted by the seller are there?



Can someone who thinks they have an adequate understanding of how the entire confirmation system works with security explain how it works? I feel as though some people here are slightly misguided.



I also don't think the value of time is directly related to security. NOTE: I may not understand confirmations correctly. However, a 10 minute block's 1 confirmation compared to needing 10 1 minute block confirmations isn't correct. The correlation here is just time. 10 minutes goes by in each block time example. If time is how some of you are describing security, I doubt that is correct. I think 1 confirmation in a 10 minute block is as secure as 1 confirmation in a 5 minute block. However, I still need to understand how confirmation security really works. You also seem to misunderstand that the Bitcoin network is HUNDREDS of times faster than the feathercoin network. I could fork any of these brand new altcoins if I jump on first.Also, I don't think the shorter block time would be much of an issue anyways. I may not understand false transactions and double spends entirely, but wouldn't faster blocks make it HARDER for someone to double spend? The following statement is made with the assumption that the attacker does not have 51% of hashpower. If someone wanted to double spend, wouldnt they need to attack each and every block until the confirmations accepted by the seller are there?Can someone who thinks they have an adequate understanding of how the entire confirmation system works with security explain how it works? I feel as though some people here are slightly misguided.I also don't think the value of time is directly related to security. NOTE: I may not understand confirmations correctly. However, a 10 minute block's 1 confirmation compared to needing 10 1 minute block confirmations isn't correct. The correlation here is just time. 10 minutes goes by in each block time example. If time is how some of you are describing security, I doubt that is correct. I think 1 confirmation in a 10 minute block is as secure as 1 confirmation in a 5 minute block. However, I still need to understand how confirmation security really works. █ sec◔nds trade █ No.1 Bitcoin Binary Options and Double Dice ▲ ▼

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Hero MemberActivity: 772Merit: 500 Re: Will a shorter block time be helpful or harmful to Bitcoin and its future? June 14, 2013, 03:40:46 PM #33 Quote from: Prophet on June 14, 2013, 01:39:46 PM Remember what has been going on with feathercoin for the past while, they've been attacked by a 51% attack, it forked their client and started orphaning everyone elses transactions.



That had nothing to do with feathercoin's block time. With a 10 minute block time, an attacker would have needed a 3% higher hashrate to pull off the >50% attack, which would have been too small of a difficulty increase to prevent an attack.



Quote from: Eri on June 14, 2013, 02:15:47 PM If you pre mine a block and have it waiting until you buy something to release it to unspand the transaction, then yes a shorter block time would help in the sense the attacker would have less time to act. but in either case your talking about small amounts of money risking a large block reward if someone else finds the next block first. with the increase in orphaned blocks i really dont think its worth it.



an attacker could try to cheat the system of a small purchase, but it would be at the risk of losing the block reward that mining the block would give them.



just to throw some numbers out there. if you found a block and held it for an attack youd be risking 3250$(BTC25 x $130)

to try to undo a transaction you just made, for anything under that dollar amount its simply not worth the attempt. for anything over, it will certainly require at least one confirmation. Not to mention, who would go into a store and attempt that transaction risking being arrested for fraud or theft. the number would have to be allot larger, ie if the transaction was the exact same value as the block reward then they have no incentive to try the attack, if the transaction was 2 times the size of the block reward they would have a 3250$ incentive to try it, and to risk jail. Again though, At that value who wouldnt require at least 1 confirmation?



This is why i really dont see it as a threat. i classify it as a non issue.



An attacker can try to defraud a large number of parties at once. If the success-event reward is larger than the cost of executing a successful double spend, then it could be economical.



A shorter block time also gives people a faster first confirmation. A single confirmation gives quite a bit more security than 0-confirmations, and would be enough for a lot of situations.



Even when more confirmations are required, a shorter block time will make the process faster. Waiting six minutes instead of one hour for six confirmations is an advantage.

That had nothing to do with feathercoin's block time. With a 10 minute block time, an attacker would have needed a 3% higher hashrate to pull off the >50% attack, which would have been too small of a difficulty increase to prevent an attack.An attacker can try to defraud a large number of parties at once. If the success-event reward is larger than the cost of executing a successful double spend, then it could be economical.A shorter block time also gives people a faster first confirmation. A single confirmation gives quite a bit more security than 0-confirmations, and would be enough for a lot of situations.Even when more confirmations are required, a shorter block time will make the process faster. Waiting six minutes instead of one hour for six confirmations is an advantage.