Fears of a potential 51 percent attack are once again brewing in the bitcoin community with news that mining pool Ghash.io has reached an uncomfortably high hashrate in the past twenty-four hours.
The bitcoin subreddit on social sharing website Reddit.com, with over ten shares on the page related to the matter.
The pool’s hashrate reached as high as 47 percent — extremely close to the 51 percent envelope that would open the door to attacks that could be carried out by the majority.
One such attack would be double-spending transactions. That is, using the same amount of bitcoin twice. Such an occurrence could have devastating consequences in the community, so it’s no surprising that members are urging others to distance themselves from Ghash.io and move to another pool.
“Ghash.io at 47% hashrate for the last 24 hours. PLEASE move to another pool if you can,” exclaims one submission on Reddit. A fellow user’s comment was voted the top saying it really isn’t that easy:
“People need to understand that simply telling people to move pool isn’t enough. This is economics, the larger miners (and the only ones that actually matter) are not going to move unless there is economic incentive . It is vital we give these miners reason to decentralize via pushing P2P or better competition.”
[ot-video type=”youtube” url=”https://www.youtube.com/watch?v=6luEMwSAS0I”]
This isn’t the first time fears of a 51 percent attack have loomed on the community.
Earlier this year, the community encountered a similar situation, equally met with as much hysteria as we’re seeing this weekend.
The news prompted Ghash.io to issue a statement on the matter at the time, in which the pool said:
“GHash.IO will take all necessary precautions to prevent reaching 51% of all hashing power, in order to maintain stability of the bitcoin network.”
They added that, “[their] plans are to expand the bitcoin community as well as utilise the hashing power to develop a greater bitcoin economic structure.”
“If something happened to Bitcoin as a whole it could risk our investments in physical hardware, damage to those who love Bitcoin and we see no benefit from having [a] 51% stake in mining.”
Ghash.io has not yet issued a statement on this occasion.
sukramko 
Scott R. 
Spekko 
Brandon Rising 
none 
max 
Pool admins should have a system to prevent large pools formation. Perhaps by introducing higher rate to join the pool after certain %. and by others pools introducing lower rates when larger pools get more dominant.
If any pool gets to 51%, this little Bitcoin experiment is going to be over real soon. I am skeptical that Bitcoin can be the financial future, when such a major flaw is so easily exploitable.
lol you novice, its a pool, the users will just stop mining there if they THINK of doing something with the power (most of which doesnt belong to the pool owners)
Lol, fail understanding of bitcoin. Create a professional video about bitcoin and people will believe it I suppose.
1. Didn’t explain what would need to occur to actually complete such an attack. Such as, predetermining the block, insuring they have mined the most recent blocks, and that their part of the chain is the main one.
2. The pool doesn’t actually CONTROL the hashing, they accept the work done by miners, but do not control the miners directly.
3. You’ll notice ghash currently still suffers from 1hr-2hr long blocks, to predetermine and control the chain, they would need to be able to successfully control 3 or more blocks in a row, and know that they can do this before a double spend attack. If this fails, they lose any bitcoins they attempted to double spend.
4. Article and video fail to mention that you would need to have someone to spend the coins with, whether it’s an exchange, or an individual, an attempt to double spend would be noticed by the second party, and inevitably be tracked back through the chain. The chain is difficult to understand, but not impossible, it’s not 100% anonymous.
With a 51% attack (as low as 31.6% as I understand) the double spend could only be on a few coin before the blockchain protocol would catch it and quarantine the double spend coin. Then the community would react, and those few coins would be marked and never be double spendable again. The risk compared to the current banksters’ system is negligable.
Not possible to mark a coin as unspendable. No one person, or entity, has the power to stop any transaction.
wrong chart. try this http://blockorigin.pfoe.be/chart.php