JorgeStolfi
Hero Member
*****
Offline Offline

Activity: 910
Merit: 1002



View Profile Personal Message (Offline)

Ignore
November 06, 2014, 08:54:11 PM

... (Otherwise he could have pre-mined a few thousand blocks in advance, in secret, and use them later to steal other people's bitcoins.) ...
hhmmm? and how on Earth would he do that ?
He posts the genesis block of the secret chain, without the headline, mines a million bitcoins, and spends them all to buy a pizza and a coke.  The pizza parlor waits, say, six confirmations before delivering the pizza.  At that time the chain is N blocks long.  Then he posts the first N+1 blocks of the secret blockchain, according to which his million coins were not paid to the parlor, but just moved to another address of his own.  This chain is adopted by the network, since it is one block longer than the legitimate one.  Now he has a pizza and a coke, and still has all of his million bitcoins; whereas the parlor's address is now  empty.
That is an altcoin.

No: if it starts with the same genesis block, and is longer, that blockchain is bitcoin, by definition; and the blocks in the other (legitimate) branch are orphan blocks, ignored.

And even if you were right, the earthlings community would figure a way around this problem if it would pop up.

I was explaining why there is a newspaper quote in the genesis block.  It was put there precisely to prevent this problem -- to prove to everybody that no one could have been pre-mining a secret chain before the genesis block was posted.