1 2012-08-05 00:32:24 <amiller> imagine if there was another bitcoin underneath the genesis block and that's just as far back as we can remember
 2 2012-08-05 00:37:27 <amiller> it's always _safe_ to use extra proofs-of-work from a dead fork in order to increase difficulty, but the chance of an actual re-org should be exponentially small
 3 2012-08-05 00:38:44 <amiller> we should also have a merkle tree (not the update-balancey kind) for our past hashes that way if someone wants to prove they're from a really old fork, they can do so in log n
 4 2012-08-05 00:39:34 <amiller> if there's another universe that also started at the genesis block that came before satoshi's
 5 2012-08-05 00:39:36 <amiller> but we both move on past it
 6 2012-08-05 00:39:42 <quintopia> hi arthur
 7 2012-08-05 00:39:48 <amiller> then neither of us would be able to convince the other of much
 8 2012-08-05 00:39:54 <quintopia> how's old norma-jean today?
 9 2012-08-05 00:40:25 <amiller> it's okay to forget history as long as we can be convinced of it later
10 2012-08-05 00:44:16 <amiller> a 33% attacker who wants to get us to fork will have to do it the hard way, because we only switch by length
11 2012-08-05 00:44:52 <amiller> but an actually larger bitcoin network from mars will be able to get us to bump our difficulty
12 2012-08-05 00:46:29 <amiller> so there are two sets of data, one is a chain, which we use for transactions and we really wish not to be forked
13 2012-08-05 00:48:00 <amiller> there's a second set of data which is just proof-of-work and we use it to gauge the strength of the network around us
14 2012-08-05 00:48:47 <amiller> a weak attacker can't fork us on length, there's no way to win on that
15 2012-08-05 00:51:06 <amiller> it's possible there's someone on jupiter that has the right to fork us but won't since he's so damn far away, if he suddenly moved closer then we'd be impressed by his work and he'd be able to convince us to merge
16 2012-08-05 00:51:14 <amiller> at least if he remembered our common history - even if we ourselves forgot
17 2012-08-05 00:51:47 <amiller> a weak attacker pretending to be jupiter will be unlikely to have a noticeable impact on our speed
18 2012-08-05 00:52:04 <amiller> it's not a nonzero possibility, but even if it happens it won't fork us
19 2012-08-05 00:52:16 <amiller> those are the two parts to the puzzle
20 2012-08-05 00:53:03 <amiller> tl;dr: slow down for proof of work, fork by length
21 2012-08-05 00:53:09 <amiller> easy
22 2012-08-05 00:55:35 <amiller> if you get merged into a larger chain, your work goes along too
23 2012-08-05 00:55:49 <amiller> along with any transactions that don't collide
24 2012-08-05 00:56:29 <amiller> we can launch a colony to jupiter with half our bitcoins
25 2012-08-05 00:56:32 <amiller> when they come back
26 2012-08-05 00:56:36 <amiller> we'll have forgotten about them
27 2012-08-05 00:56:54 <amiller> but they'll be able to prove they have coins from that era
28 2012-08-05 01:04:51 <amiller> it's important to be able to go from each proof of work to the genesis block (or as far back as we care about) in log n