Tor Reproducer

This is a tool you can use to verify that the version of Tor used by Briar was built exactly from the public source code and no modifications (such as backdoors) were made.

More information about these so called reproducible builds is available at reproducible-builds.org.

The source code for this tool is available at https://code.briarproject.org/briar/tor-reproducer

How to use

Make sure the version of Tor you want to verify is included in tor-versions.json.

Verify that you have docker installed:

docker --version

If this command does not work, please install Docker and continue once it is installed.

Using our pre-built image

If you trust that our pre-built Docker image was build exactly from its source, you can use it for faster verification. If not, you can read the next section to learn how to build the image yourself. Then you are only trusting the official debian:stable image which is out of our control.

Otherwise, you can skip the next section and move directly to Run the verification.

Building your own image

Check out the source repository:

git clone https://code.briarproject.org/briar/tor-reproducer.git

Build our Docker image:

docker build -t briar/tor-reproducer tor-reproducer

Run the verification

To verify a specific version of Tor, run

docker run briar/tor-reproducer:latest ./verify-tor.py [version]

Where [version] is the version of Tor you want to test, for example 0.3.3.6.

You can find a list of versions in Tor's source code repository. Just remove the tor- from tor-0.3.3.6.

If you leave out [version] it will build the latest version that was registered in tor-versions.json.

In case there is an issue with the verification of an old build, this might be caused by an update of the container. You can try to use the original container by running:

docker run briar/tor-reproducer:[version] ./verify-tor.py [version]

There should be a tag with the name [version] in this repository that you could be used to reproduce the old container. Note that this will not work if the issue is caused by an updated Debian package.

Historical changes

The Tor 0.3.x series had a different build system than the 0.4.x series. Please use a version of tor-reproducer that starts with 0.3 to reproduce those.

Only build Tor

To build a specific version of Tor, run

docker run briar/tor-reproducer:latest ./build_tor.py [version]