Quote from: erk on May 21, 2013, 05:45:11 AM

Quote from: Maged on May 21, 2013, 05:03:33 AM

Yes, but like most things in life, an important balance between too much and too little exists. Shorter block times make it harder for <50% attacks to succeed, true, but by increasing the number of orphans, it decreases the effective hash rate of the network, making a >50% attack potentially much easier. Bitcoin considers the potential risks of a successful >50% attack to be very high, so Satoshi chose a long block time.

This seems like mathematical nonsense, please prove to me that for example if there are 4 times more chain splits with 1/4 the block time, that there are less iterations to arrive at consensus within the same duration. I bet you can't, because the increase in chain splits is trivial compared to the increase in blocks.

LTC has certainly proven for a long time that a shorter than 10min block target is perfectly viable.

Of course a block time shorter than 10 minutes is perfectly viable! I never said that it wasn't. My point was that there exists a point where the orphan rate caused by a shorter block time ends up outweighing the benefits of a shorter block time. This starts to matter earlier than you may think because an orphan rate of just a few percent would be enough to encourage miners to centralize. However, ignoring that, here's an extrapolation of the reduction in effective hash rate as a network the size of Bitcoin reduces block time (the Bitcoin network currently sees about a 1% orphan rate):

Blocktime in seconds	Reduction in effective hashrate
600	1%
300	2%
150	4%
75	8%
37.5	16%
18.75	32%
9.375	64%

As you can see, two and a half minutes per block isn't actually all that bad in the reduction of effective hashrate, but I wouldn't want to go much lower than that.