Take a money as a third, and even more, I believe many people have imagined. Digital currency is essentially a string of characters, copy, it can not be as complete as like as two peas, two copies, three copies, even more than the use?
Today, we have a chat: under what circumstances, we can put a digital currency as two gold, three gold medals, even more to use?
The “double” and “51% force attack”
The so-called “double”, that is easy to understand: a money spent two or more times.
Block chain transactions under normal circumstances, this is (to bitcoin transactions for example): Li Lei bought a diamond ring for energy-saving with 1 BTC, this time Li Lei from his wallet out of 1 BTC to the gold shop owner’s BTC account, the transaction will be verified and recorded in the block packing miners height N the block, in Li Lei’s account is reduced by 1 BTC, the gold shop owner accounts increased 1 BTC.
If Li Lei took control of the whole network 51% bitcoin work force, have the ability to modify the block trading records, he wants to double the BTC, what will he do?
In the end he will buy Diamond paid after BTC, N-1 after the modification of all block data block height, thereby forking out a new chain.
Because Li Lei has 51% operator, a new chain will soon become the longest chain, so it is accepted as the backbone of all nodes.
In this chain, without Li Lei and gold shop owner’s transaction records, Li Lei buy a diamond ring BTC is still in your wallet account, also got a diamond ring, this is through the “51% force attack” the successful implementation of the “double”.
Launched the “51% force” attack cost
In fact, launched the “51% force attack” costs, and we did not think so high, and low to surprise you.
According to Crypto51 December 16th data, as the world currency (Dash) launched the 1 hours of “51% force attack” cost is $2432, and be able to rent the whole network is 75%; Ethernet (ETC) classic Fang can rent to the whole network of 82% forces, 1 hour attack cost is $3441; Bitcoin (Private a bifurcated currency bitcoin) to rent the whole network is 2.646 times, 1 hours before the attack cost $46.
Why do some of the currency launched “51% force attack” costs so low? There are several reasons:
1, first of all, based on many PoW consensus mechanism of currency, due to the involvement of the mining industry, finally force is very small, it is easy to be launched attack;
2, with the advent of the ASIC mill, with a large number of machine is very easy to get small currency is 51%;
3, the rental market is there, due to the 51% force launched an attacker, low cost, short time is from market rent is enough for. Because force is rented, the attacker can Jintuiziru.
The above three is not for those involved in mining, the whole network is also relatively low currency.
For this is bitcoin already has a huge force chain, launched 51% of the calculated force attack, cost is very large, and the key is to rent not enough computing power, so I want to be a successful attack by force bitcoin almost impossible, this is why many people bitcoin have “faith” the reason.
If a currency suffered a successful “51% force attack”, the chain of data has been tampered with, the currency price rate will probably become zero, not worth a hair.