[Cryptography] ghash.io hits 50% of the Bitcoin compute power

[grarpamp]

On Fri, Jun 13, 2014 at 5:44 PM, Perry E. Metzger <perry at piermont.com> wrote:
> On Fri, 13 Jun 2014 12:46:46 -0400 Phillip Hallam-Baker
> <phill at hallambaker.com> wrote:
>> On Fri, Jun 13, 2014 at 9:51 AM, Perry E. Metzger
>> <perry at piermont.com> wrote:
>>
>> > The security of Bitcoin depends on no one group burning more than
>> > half the compute cycles. As of today, of course, the graph looks
>> > like this.
>> >
>> > https://imgur.com/PPVr0Wv
>>
>> This is only a risk if you want to spend or transfer your coins. If
>> you are a hoarder it doesn't matter.
>
> That is untrue. The binding between your private key and a set of
> coins depends on the integrity of the blockchain itself.

Wuh, false, last I checked unlike other networks, there are no
serialized "coins" being passed around. You're awarded
ownership of a balance in a public ledger by signatories that check
your initial work of solving a hard math problem... the digging your own
gold part of "mining". You spend off parts of that balance by signing it
away to others and injecting that transaction to the net for
validation by signatories (the other role of miners), who then add
it to the ledger. If everybody agrees that todays height is legit, nobody
can go back in time to alter that, because the millions
of people with that legit historical ledger will call bullshit.
51+% only matters to future proposed ledger entries.
Hoarders balance are safe, but will only have use if there's
a good net left post-attack to transact upon. It's hard
to do a targeted attack with small majority. And some
people may continue trading unawares under a growing
majority. It's best to watch the pie charts, forums, and any
warnings from the client alert net and boycott trading until
mining reverts to normal.

https://en.bitcoin.it/wiki/Weaknesses#Attacker_has_a_lot_of_computing_power
https://en.bitcoin.it/wiki/Alerts