A BitMex Research survey has revealed that the new post-fork upgrade of Bitcoin Cash ABC introduces certain vulnerabilities in its protocol.
Bitcoin ABC has updated its client, the new version 0.18.5, incorporating control points every 10 blocks of the chain. According to the developers of this update, the intent is to prevent block reordering attacks (reorgs), following the constant threats received by the Bitcoin Cash (BCH) network after the bifurcation of this November 15. However, while the update reduces the risk of the intruders rewriting the string, introduces a new attack vector that malicious miners can exploitAccording to BitMEX.
In the publication of the research team BitMEX, home of change of cryptoactives, ensures that the update allows an alternative attack to the reorder. As they explain, the addition of the checkpoint to every 10 blocks could allow a division of the "honest chain," that is, the main chain. The investigation states that as soon as block 10 has been produced, the attacker could undermine a parallel chain hidden from that point. In this way, some miners in the main Bitcoin Cash ABC network could first undermine the malicious block, while others would undermine the honest block.
Researchers at BitMEX believe that control points can be "conflicting" for the Bitcoin Cash ABC network. In addition, they consider that the possibility of causing a split in consensus "could be as damaging to the network" as the hostile reorganization of the blocs.
On the other hand, Bitcoin developer Eric Wall says control points for every 10 blocks also open the possibility that malicious miners may also attack network nodes that "are still in the initial synchronization" or those that have been temporarily disconnected.
According to Wall, the desynchronized nodes could receive the blocks of the malicious chain first and that would make that the honest chain was rejected from that moment. In this regard, BitMEX claims that this feature removes the Bitcoin ABC update from what is proposed in the Bitcoin white paper, which states that "nodes can come out and join the network whenever they want"; replacing it with the need for us to be online 24/7.
Wall also notes that only It is necessary to mine 10 blocks to take control of the network. Attack said, according to the developer, has a cost of 27,000 and does not require the processing power needed to perform a 51% attack. Indeed, computer ensures that only an S9 Antminer is required to manage the malicious chain.
In addition, possible alternative attacks are not the only problems that the 0.18.5 version of Bitcoin Cash ABC faces. Another point of criticism of the new implementation is that it "gives developers more power and increases centralization." The speaker and disseminator of Bitcoin Andreas Antonopoulos commented through his Twitter account that "we must be skeptical about the change of power" in decentralized networks.
In this regard, BitMEX makes the caveat that the inclusion of these control points does not provide developers with more power because, unlike the control points that the Bitcoin network had, in the new version of Bitcoin ABC client "points are generated automatically by the node software and not by the development team."
However, BitMEX states that it is not at present clear how the inclusion of these control points symbolizes a "substantial improvement" for the security of the BCH ABC network.
At the same time, the researchers believe that the new Bitcoin ABC client update did not have "due diligence" prior to launch. Above all, considering that the inclusion of control points means a fundamental change in the dynamics of consensus.
After the threats, there is a truce
The pre- and post-bifurcation tensions of Bitcoin Cash were numerous. The ecosystem was plunged into a battle of hashrate and threats from mining pools. Despite the threats, the bifurcation occurred, and this led to the release of an update of Bitcoin Cash ABC.
Days after the launch of the update, Bitcoin SV promoter Calvin Ayre proposed a truce between the altcoins. Ayre said he feels it is time to abandon the battle because Bitcoin SV is about the real Bitcoin Cash. In addition, the CoinGeek boss agreed not to file a legal action against those who attacked his pool during the fork or against those who attacked his site a week ago.
In turn, the developers and promoters of Bitcoin Cash ABC did not comment on this situation.
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