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.