Onion Module (Java)

This repository provides a Java-based onion routing implementation compatible to the specification of the VoidPhone application. To increase anonymity, a TCP-based Onion API offers tunnel building, data transport and sending of cover data. In addition, we increase security by refreshing every built tunnel after a fixed time interval.

This module requires a running Onion Auth and RPS module for encryption and random peer selection.

Execute the Onion Module

To execute the Onion module, you can either use the pre-built version contained in the release/ directory or build from source. Java 8 is required for execution. Use this command to run the Onion module:

release/# java -jar Onion_1.0.jar --config path

path is the path to the configuration file used by the Voidphone application. Following parameters are required in the onion section:

• hostkey = <path_to_pem_key> | Path to the key used by this peer.
• listen_address = <public_ip>:<port> | P2P address of this peer.
• api_address = <pubic/private_ip>:<port> | Address used for API connections to the Onion module
• round_interval = <round_interval_in_seconds> | Round interval the Onion module shall use
• intermediate_hops = <number_of_intermediate_hops> | Number of intermediate hops in the tunnel between this peer and the receiver.

In addition, api_address = <pubic/private_ip>:<port> is also required in the rps and auth section.

A sample configuration is contained in the config/ directory. (Adapted from the bootstrap.conf in the testing framework)

Help and Command Line Arguments

To display the help text of the Onion module following command:

release/# java -jar Onion_1.0.jar --help

Subsequent command line arguments are supported:

• help: Display the help text.
• config: Path to the configuration file. (Required)
• loglevel: The log level used by the Onion module (Default: INFO). Currently all log messages will be printed to stdout. (Optional)

Building from Source

Maven is required to build the Onion module from source. We tested the build using Maven-3.3.9 (Apache License 2.0).

The Java source code of the project is contained in the src/ directory in the repository. As Maven is used for dependency and build management, execute the following command in the src/ directory to build the project from source:

src/# mvn clean package

After a successful build, Maven creates Onion_1.0.jar in the src/target/ directory. This jar file contains all necessary dependencies.

The standard build will execute the our unit tests and a large integration test (Build tunnel, send data, destroy tunnel with mockups). To skip all tests use following command to build the project:

src/# mvn clean package -DskipTests

Dependencies

Our implementation has the following dependencies:

• jUnit-RELEASE (currently 4.12): Eclipse Public License 1.0
• Bouncy Castle-1.57: MIT X11 License
• Netty-4.1.12.Final: Apache License 2.0
• Google Guice-4.1.0: Apache License 2.0
• log4j-2.8.2: Apache License 2.0
• ini4j-0.5.1: Apache License 2.0

As we are using Maven, all dependencies will be downloaded automatically during build.