Continuing on for most of the year the market decline and the decline Hasrat cryptocurrency makes many of them more vulnerable to attack 51%, which was confirmed in another such incident, this time with cryptocurrency Vertcoin (VTC).
Since mid-November, the attackers managed to make at least 15 episodes of double-spending of coins worth more than $100,000. In total there were 22 cases of reorganization of the chains, one of which was to rewrite more than 300 of the latest blocks. This, in particular, wrote a safety engineer Coinbase mark Nesbitt.
VTC experienced a 300 block reorg last night from vertcoin
Here is an example of a block in which there was initial spending about 1,300 VTC. The attack of the reorganization of this unit was excluded from the main chain and replaced. The same coins were spent again in another unit.
Attack to reorganize blocks allow attackers to execute transactions (for example, to send the coins to the exchange, wait for confirmation, sell them and withdraw bitcoins), and then use the dominant, Hasrat network with the aim of creating a new alternative chain. As a result, the history of the blockchain will be rewritten in such a way that the entry about sending coins to the exchange will not be saved.
In the block chain algorithm Proof-of-Work is the rule “the longest chain”, that is always true is the chain with maximum number of blocks. If you find these blocks fast enough, the attacker can rewrite history and then make another transaction and re-sell those same coins.
According to Nesbitt, the developers of some of the cryptocurrencies with the bulk transaction history claim that they are secure enough to allow yourself to integrate the algorithms for hashing on specialized ASIC-devices and thus provide an increased level of decentralization. However, in his opinion, such an approach harms the security of the system, and confirms that the sample Vertcoin.
Unlike bitcoin, Vertcoin uses the so-called ASIC-resistant algorithm, i.e., does not require specialized equipment for mining. For comparison, for the same attack on bitcoin attackers would have had a very long time to accumulate power, spending huge amounts of money before it theoretically would be possible.
In the case of Vertcoin, in addition to damage the reputation of the network itself , the main victims are the exchanges which are in fact paid out of his own money and paid for the lack of technical audit and listing inherently insecure coins.
The estimated cost of the attack 51% within one hour when using available to rent computing resources can, for example, be found on the website Crypto51. As can be seen, for some cryptocurrencies the cost of such attacks is extremely low. So, the attack on the same Vertcoin will cost $104, even less — $14 per hour – will cost the attack on Einsteinium.
Earlier this year that the number of attacks 51% of the altcoins will rise, said the head of the Lightning Labs Elizabeth stark. Among the latest attacks, you can call the incident with Ukrainian cryptocurrency Karbo [Karbovanets] AurumCoin. Attack on AurumCoin this should exchange Cryptopia more than half a million dollars.
It is noteworthy that the project Vertcoin has informal links with Digital Currency Initiative Massachusetts Institute of technology (MIT) and is also known for the implementation of protocols for Segregated Witness and Lightning Network.
Source
