Bitcoin Core’s privacy fix reaches v32 code while the v31 patch remains open
Bitcoin Core merges a privacy fix into its 32.x source branch to prevent private-broadcast connections from linking with standard node connections, while the 31.x backport patch remains open.
A privacy fix has been successfully merged by Bitcoin Core into its 32.x source branch, correcting a behavior that could potentially link private-broadcast connections with standard node connections. As of Oct. 8, the backport for the 31.x branch is still open, meaning users who utilize this feature on version 31.1—the latest stable release—must wait for the patch to be applied. It is worth noting that private broadcast remains disabled by default.
The original modification reached the main development branch on Sept. 25, followed by the Oct. 1 backport. On Oct. 6, the separate proposal aimed at bringing this repair to version 31.x earned approval from reviewer vasild and was given a 31.2 milestone. However, this assignment does not guarantee a specific release date.
Currently, the official download page continues to feature 31.1 as the most recent version. Meanwhile, the 32.0 download directory holds test candidates rather than finalized release files, which includes rc3 binaries carrying an Oct. 6 date.
The opt-in path at risk
This privatebroadcast setting is activated by users submitting transactions via sendrawtransaction, the specific command utilized for broadcasting a raw transaction across the network. This pathway relies on dedicated, short-lived connections to Tor or I2P peers, as well as to IPv4 and IPv6 peers routed through Tor. The concern regarding connection-linking targets this particular private-broadcast function rather than nodes operating on standard configurations.
At the root of the issue is “discouragement,” which is how Bitcoin Core manages misbehaving peers and other connected nodes. According to the original fix’s reviewers, discouraging a private-broadcast peer could inadvertently trigger observable changes in node behavior from an external perspective. Additionally, standard discouragement could terminate other connections linked to that exact peer address. Such shared consequences could expose clues to an external observer, bridging the gap between private connections and regular node operations.
The newly introduced patch successfully divides these behaviors. Private-broadcast peers are now shielded from standard discouragement procedures, though misbehaving private peers will still face disconnection. Similarly, discouraging a regular peer no longer results in the termination of private-broadcast connections that happen to share its address.
An earlier IP-address leak was previously detailed in Bitcoin Core’s 31.1 release notes, which revealed that certain private-broadcast connections would utilize the clearnet instead of the intended privacy network. While that previous correction focused on connection routing, this recent update specifically tackles the observable side effects of peer management.
Furthermore, developers have labeled the private broadcast feature as experimental while scaling back its privacy guarantees to mere risk reduction. For operators running the older branch, a completed 31.x backport alongside an official release containing it are the necessary next steps.
Frequently Asked Questions
01What is the purpose of the Bitcoin Core privacy fix?
The fix addresses a vulnerability that could correlate private-broadcast connections with standard node connections by separating peer-discouragement behaviors.
02Is the private broadcast feature enabled by default?
No, private broadcast is disabled by default and is considered an experimental feature focused on risk reduction.
03Which Bitcoin Core versions are affected by the backport status?
The fix has been merged into the 32.x source branch, while the backport for the 31.x branch remains open as of Oct. 8, leaving users on version 31.1 waiting for the update.
