Quote from: Ron~Popeil on July 09, 2014, 06:44:46 PM

Quote from: byt411 on July 09, 2014, 06:24:00 PM

Quote from: franky1 on July 09, 2014, 05:38:46 PM

what the OP is trying to say is that knowing difficulty is changed every 2100 blocks.

he will set up a private network of 2 PC's and at block 2098 he will set both computers time to be year 2100, thus as mining 2 more blocks. in this closed network. then the protocol in his theory will see that the blockchain has not mined blocks for 85 years and then give him super easy difficulty..

now the reality. when he rejoins the network he wil be all alone on his fork and everyone else will mine as usual not realising he exists, his coins from those 2 blocks would show as invalid and unspendable (wont confirm if he tried to send them) and he will get on with his life.

OP you also have to realise that you trying to (in basic principle) solo mine block 2098 and 2099, would be still at an extremely high difficulty before the change, which unless you had a asic farm, would take you not 20 minutes.. but days or weeks if lucky..

so dont waste your time on this. many thousands of people have been there, done that.

so heres the T-shirt

the other theory is to gather soooo much hash power to rival Ghash.oi etc. that if lucky he is the one that mines the critical block 2099 and it shows a timestamp of the year 2100..

goodluck, have you got over $10mill of equipment to try?

Of course, a regular person wouldn't be able to do so, but Even a small pool like Bitminter, or Bitmaintech's AntPool, or KnC's "Testing Facility" could easily accomplish this without controlling 51% of the network. After they find that one block, which wouldn't take long, they would be able to start the cycle.
I think this deserves a bit more attention.

I don't pretend to know enough to comment on the specifics of such an idea. I do think as an academic exercise it is good to be aware of this kind of stuff in order to stay ahead of people that would try to game the system. I don't believe most such attacks would succeed in getting a bunch of coins, but they can cause chaos and fear which does affect our wealth.

If no countermeasure is put in place, the attackers will just grab all block rewards with very little effort, and all coins will get mined in very little time, so it is a bunch of coins.