Bitcoin Block Time Halved To Five Minutes Amid Exponential Network Growth

&quot;A common misconception is that transactional confidence is based on time&quot;<p>Transactional confidence is based on the probability of someone compromising the network for enough blocks to undo a spend that you&#x27;ve already honored (IE you gave them what they paid for, then they undo the transaction). At 6 blocks, you are assuming that an attacker won&#x27;t have the computational power to reverse 6 blocks in a row.<p>When blocks come out every 2 hours, that means you need to find every single block for 12 hours, or essentially control the blockchain for a long time.<p>When the block rate is down at 5 minutes, you only need to control the network for 30 minutes - you have more chances to get lucky and undo 6 transactions in a row in your 12 hours of purchased computing time.<p>A halved block rate does not mean you need less computational power, but it does mean that computational power is probably cheaper and 6 blocks worth of power is going to be more affordable.

Inaccurate title. The network still sets the difficulty every 2016 blocks ( i.e. 2 weeks) so that it takes 10 minutes on average to create a block.<p>Right now, however, people are adding so much computational power in that intervening two weeks, that by the end of those two weeks it takes 6 minutes to create a block, not 10.<p>This is presumably due to custom hardware mining rigs coming online since they just shipped.

If only the bitcoin algorithm could have accounted for incredibly various technical and sociological issues.<p>Good thing Moore&#x27;s Law somehow exists and has maintained the curve perfectly despite not being a law, despite somehow not making any reference to the consumer activity that seemingly drives it, and a heavily innovation-constraining duopoly for every chip that is used in desktops&#x2F;laptops.<p>Some times I feel like the computer industry really is driven by magic smoke.

Some alt-coins have been destroyed by the in-rush of massive hashing power, which caused a difficulty-adjustment up, followed by an exit of that hashing power, leaving block-progress so slow that it would take &#x27;forever&#x27; (impractically long) for the next normal compensating adjustment-down to happen.<p>Since one of the joys of Bitcoin is using it to exercise one&#x27;s paranoid imagination, consider scenarios where somehow, an enemy of Bitcoin (or promoter of an alternative) can somehow <i>disable</i> or <i>redirect</i> all that ASIC power in a short time frame.<p>Perhaps, in cahoots with the ASIC makers, some magic input can cause them to begin malfunctioning (either temporarily or permanently). Or, a cartel controls enough SHA256 power to withhold capacity, and switch to a NewCoin needing the same hashing resources, in rapid coordinated succession. Or both.<p>It might be hard for Bitcoin-prime to adapt in time, while NewCoin&#x27;s deep-pocketed backers from the USG, CCP, or evil lectroids of Planet-X tempt miners and Bitcoin balance holders to switch to NewCoin, perhaps via an initial endowment mechanism which requires the irreversible destruction&#x2F;relinquishment of old Bitcoin balances.<p>Ah, good times. Good Stephensonian-science-fictional times.

If only people were this determined to run things like Folding@Home....

Given the exponential growth in the network hash rate, how much sooner than 2140 can we expect the last bitcoins to be mined?