Tor Support in Zcash¶
Warning: Do not assume Tor support does the correct thing in Zcash; better Tor support is a future feature goal.
It is possible to run Zcash as a Tor hidden service, and connect to such services.
The following directions assume you have a Tor proxy running on port 9050. Many distributions default to having a SOCKS proxy listening on port 9050, but others may not. In particular, the Tor Browser Bundle defaults to listening on port 9150. See Tor Project FAQ:TBBSocksPort for how to properly configure Tor.
1. Run Zcash behind a Tor proxy¶
The first step is running Zcash behind a Tor proxy. This will already make all outgoing connections be anonymized, but more is possible.
- Set the proxy server. If SOCKS5 is selected (default), this proxy server will be used to try to reach .onion addresses as well.
- Set the proxy server to use for Tor hidden services. You do not need to set this if it’s the same as -proxy. You can use -noonion to explicitly disable access to hidden service.
- When using -proxy, listening is disabled by default. If you want to run a hidden service (see next section), you’ll need to enable it explicitly.
- -connect=X, -addnode=X, -seednode=X
- When behind a Tor proxy, you can specify .onion addresses instead of IP addresses or hostnames in these parameters. It requires SOCKS5. In Tor mode, such addresses can also be exchanged with other P2P nodes.
In a typical situation, this suffices to run behind a Tor proxy:
$ zcashd -proxy=127.0.0.1:9050
3. Automatically listen on Tor¶
Starting with Tor version 0.2.7.1 it is possible, through Tor’s control socket API, to create and destroy ‘ephemeral’ hidden services programmatically. Zcash has been updated to make use of this.
This means that if Tor is running (and proper authentication has been configured), Zcash automatically creates a hidden service to listen on. Zcash will also use Tor automatically to connect to other .onion nodes if the control socket can be successfully opened. This will positively affect the number of available .onion nodes and their usage.
This new feature is enabled by default if Zcash is listening (
requires a Tor connection to work. It can be explicitly disabled with
and, if not disabled, configured using the
To show verbose debugging information, pass
Connecting to Tor’s control socket API requires one of two authentication methods to be
configured. For cookie authentication the user running zcashd must have write access
CookieAuthFile specified in Tor configuration. In some cases this is
preconfigured and the creation of a hidden service is automatic. If permission problems
are seen with
-debug=tor they can be resolved by adding both the user running tor and
the user running zcashd to the same group and setting permissions appropriately. On
Debian-based systems the user running zcashd can be added to the debian-tor group,
which has the appropriate permissions. An alternative authentication method is the use
-torpassword flag and a
hash-password which can be enabled and specified in