The Bitcoin (BTC) network has been steadily recovering in terms of running BTC nodes after a major outage on the Tor network.

According to the latest data from node monitoring resource Bitnodes, Tor-enabled Bitcoin (BTC) nodes are back to normal following almost a full-swing crash in early January 2021. As of Jan. 13, the number of reachable Tor-based BTC nodes amounted to 2,581, up from as few as 122 nodes on Jan. 9.

Based on Bitnodes data, Tor-enabled Bitcoin nodes make up a significant part of the Bitcoin network, normally accounting for about 25% of totally reachable running nodes. According to the latest recorded data, Tor-based nodes made up over 23% of total BTC nodes on Jan. 13.

According to Bitnodes, the current number of Bitcoin nodes amounts to 11,190 nodes, up from around 8,300 on Jan. 7.

Number of reachable Bitcoin nodes over the past 90 days. Source: Bitnodes

A Bitcoin node is a computer connected to other computers to host and synchronize a copy of the entire Bitcoin blockchain and essentially keep the entire network running. Tor-based Bitcoin nodes are a type of node implemented privately using the Tor anonymous network.

The latest dip in Tor-enabled BTC nodes is likely to be caused by a recent crash on the Tor network. On Jan. 10, Tor Project officially announced that the Tor network was experiencing instability due to an implementation bug in its v3 onion service. Tech-focused news agency TechNadu reported that the outage was likely due to a hacker attack.

The downtimes in the Tor network subsequently affected a large number of Tor-enabled or so-called “onion” websites including private Bitcoin wallets and exchanges like Wasabi and Bisq. On Jan. 11, Wasabi reported that it managed to keep its services intact using a fallback system. “If the Tor onion service of the backend becomes unavailable for the user, the wallet falls back to communicating with the backend's clearnet endpoint, still over Tor,” Wasabi wrote.

A spokesperson for Tor Project told Cointelegraph that there is no evidence that the Tor Network was under an attack but was rather triggered by traffic overload. “The outage may have come from a poorly written custom Tor client requesting directory information too often,” the person said. There is also no evidence that the traffic overload was actively trying to hurt v2 onions, the representative noted.

According to the spokesperson, the network “was always fully intact" but the traffic overload “destabilized v3 onions” due to a bug. As a result, v3 onion services were inconsistently reachable for a few hours on Jan. 9 and again for a few hours on Jan. 10, the person stated. A fix for the underlying bug is now in an alpha release on the Tor Project website.

Disclaimer: This article was updated to add comments from a spokesperson for Tor Project.