Number of Reachable BTC Nodes to Fell by 15%

Reduction in nodes number is associated with the miners which stopped operation due to a sharp drop in profits
24 December 2018   1200

The Bitnodes data show that in 2018 the number of reachable nodes in the Bitcoin network decreased by 15.5%. At the time of writing, the number was 10,004. During the same period, the number of unreachable nodes also decreased by 33%, from 98,000 to 65,500, according to CCN.

A reachable bitcoin node is a node that receives and sends connection requests from the network, and also keeps records of all transactions. At the same time, the unreachable node only establishes outgoing connections, but does not accept incoming ones.

Reducing the number of reachable nodes is fraught with increased centralization of the Bitcoin network and in the future may lead to an attack of 51%. According to the publication, the reduction in nodes number is associated with the miners which stopped operation due to a sharp drop in profits.

Potentional Vulnerabilities Found in ETH 2.0

Least Authority have found potentional security issues in the network P2P interaction and block proposal system
26 March 2020   976

Technology security firm Least Authority, at the request of the Ethereum Foundation, conducted an audit of the Ethereum 2.0 specifications and identified several potential vulnerabilities at once.

Least Authority said that developers need to solve problems with vulnerabilities in the network layer of peer-to-peer (P2P) interaction, as well as in the block proposal system. At the same time, the auditor noted that the specifications are "very well thought out and competent."

However, at the moment there is no large ecosystem based on PoS and using sharding in the world, so it is impossible to accurately assess the prospects for system stability.
Also, information security experts emphasized that the specifications did not pay enough attention to the description of the P2P network level and the system of records about Ethereum nodes. Vulnerability risks are also observed in the block proposal system and the messaging system between nodes.

Experts said that in the blockchains running on PoS, the choice of a new block is simple and no one can predict who will get the new block. In PoS systems, it is the block proposal system that decides whose block will fall into the blockchain, and this leads to the risk of data leakage. To solve the problem, auditors suggested using the mechanism of "Single Secret Leader Election" (SSLE).

As for the peer-to-peer exchange system, there is a danger of spam. There is no centralized node in the system that would evaluate the actions of other nodes, so a “malicious" node can spam the entire network with various messages without any special punishment. The solution to this problem may be to use special protocols for exchanging messages between nodes.