Vulnerability in the Bitcoin network is found at the request of the US Department of Defense

A study by Trail of Bits commissioned by the U.S. Department of Defense found that 60% of bitcoin network traffic passes through just three Internet providers

As explained by analysts in the Trail of Bits report «AreLedgers.pdf">Blockchains Decentralized?», there are several scenarios in which centralized control over the bitcoin network can be gained. For example, companies providing access to the network can deny service to any node or reduce the quality of communication (channel width).

Researchers have found that 21% of bitcoin nodes use an old version of the Bitcoin Core open source software that has vulnerabilities. The operation of all DLT (distributed ledger system) nodes on the latest version of the software is extremely important, otherwise consensus errors will lead to a split in the blockchain.

Currently, the largest bitcoin provider is the Tor network, which routes traffic from about 50% of nodes. Half of the nodes operate through the Tor network, and the other half through onion addresses. Interestingly, it is not only cryptocurrencies that have faced the problem of network traffic. Yesterday, Cloudflare’s network of high-speed servers discovered bugs in the system that caused many cryptocurrency exchanges to suspend their work — this happened after Cloudflare updated its system.