Here is my last article regarding how a PoW base cryptocoin can achieve a 25 second confirmation time using a 5-second block interval, and still keeping the coin safe from stale blocks and competing chains.

http://bitslog.wordpress.com/2014/02/17/5-sec-block-interval/


I think this is the first time such a short block intervals is studied. The techniques I used are not new, but I've managed to simulate the network and convince myself that it actually works quite fine.

I'd love to hear comments...