[ExI] Kevin Dowd on Bitcoin

[Mirco Romanato]

Il 17/01/2015 17:48, Harvey Newstrom ha scritto:
> Agreed, It's not the hashrate (speed or power) that allows this.  It
> is the conflict resolution protocol that allows this.
> 
> Whenever different reporting entities disagree on something, they
> vote.  Who mined a bitcoin first if multiple people claim it?  Who
> received a bitcoin first if multiple purchases were made with the
> same bitcoin?  Whose transactions do we accept and whose do we
> reverse when there are record disputes?  They vote.

There is not "who mined the bitcoin(s) first".
There is "The the block(n) is valid or not?"

If two blocks are created at the same time at the same level of the
blockchain and they are distributed to the network nodes, there is no
voting on anything.

The nodes receiving block(n.a) first will add it to their blockchain,
the nodes receiving block(n.b) first will add it to their blockchain.

This is called a fork.

The miners accepting block(n.a) will start mining the successive
block(n.a+1) and the miners accepting block(n.b) will start mining the
block(n.b+1)

The first to find a new block will start distributing it to the network;
if block(n.a+1) is found first, every block with block(n.b) will be
presented with a valid blockchain longer then their. They will discard
the old blockchain (in this case only block(n.b) and accept the longer
blockchain as valid (block(n.a) and block(n.a+1).

Given the latency of the network, the speed of transmission and the
average probability to find a block every ten minutes, the chance to
have an orphaned chain longer than 6 blocks are so small it is
improbable it will ever happen before the universe die.


> Anybody with 51% voting rights can theoretically outvote the others
> any time they want.  Google for bitcoin 51%, majority, race attack,
> Finney attack, double-spending, history modification, selfish mining,
> time limits, and similar terms for more information.

There are no voting rights. Just provable work done.

Mirco