Bitcoin Core’s privacy fix reaches v32 code while the v31 patch remains open

Users enable the privatebroadcast option for submissions through sendrawtransaction, the command for sending a raw transaction to the network. That path uses dedicated, short-lived connections to Tor or I2P peers, or to IPv4 and IPv6 peers through Tor. The connection-linking concern applies to this private-broadcast activity, rather than every node running the default configuration.

The problem involves “discouragement,” Bitcoin Core’s handling of certain misbehaving peers, the other nodes it connects to. Reviewers of the original fix explained that discouraging a private-broadcast peer could alter node behavior visible from outside. Normal discouragement could also disconnect other connections to the same peer address. Those shared effects could provide an observer with a clue linking the private connection to ordinary node activity.

The patch separates those behaviors. Private-broadcast peers are excluded from normal discouragement handling, while misbehaving private peers are still disconnected. Conversely, discouraging an ordinary peer no longer disconnects private-broadcast connections sharing its address.

Bitcoin Core’s 31.1 release notes describe an earlier IP-address leak: under some circumstances, private-broadcast connections used clearnet instead of the enabled privacy network. That repair addressed how connections were routed. The newer change addresses observable effects of peer handling.

Developers also marked private broadcast experimental and narrowed its privacy claims to risk reduction. For users on the older branch, the next steps remain a completed 31.x backport and a release containing it.