Quote from: Point at Infinity on April 14, 2013, 06:47:05 PM

Quote from: Crypto Canary on April 14, 2013, 02:52:02 AM

So, as I said before, it's completely arbitrary?

Not completely. The time has to be long enough for every node to verify the block. 10 minutes was chosen by Satoshi as a compromise between network security and confirmation times. In hindsight a smaller value might have been better, but not much smaller. With older versions of Bitcoin it sometimes took over a minute before every node received the block, and there needs to be a wide margin for safety.

This. +1 rare for noob to get it that accurate.

To expand upon what Infinity said ...

Any block interval is a compromise. 10 min, 1 min, 60 min, etc. There is no right or wrong. It is a compromise. Remember the actual block time will vary. When blocks can't propagate the network fast enough and competing blocks are produced that results in orphans. The % of orphans direct reduces the security of the network. Currently Bitcoin w/ 10 minute blocks (and relatively small blocks) has about 1% orphan rate. That means 1% of hashing power is wasted and doesn't improve security. As blocks get larger the orphan rate will rise (although faster CPU and higher bandwidth connections improve the orphan rate).

10 minutes is a compromise between confirmation times and network security. Really unless you are accepting 1 confirm txs faster block interval won't make tx validate faster. If you wait for 6 confirmations on a 10 min block chain then with equivalent hashpower you should wait 24 blocks on a 2.5 min block chain. If you are willing to accept 4 confirmations on a 2.5 minute blockchain then 1 confirmation on a 10 minute blockchain provides equivalent security.

Really a shorter block interval only helps if your business accepts 1 confirm txs (because 1 confirm is always more secure than 0 confirms regardless of the block interval).