The QUIC Copier (qcp) is an experimental high-performance remote file copy utility for long-distance internet connections.

• 🔧 Drop-in replacement for scp
• 🛡️ Similar security to scp, using existing, well-known mechanisms
• 🚀 Better throughput on congested networks

• Well tested: Debian and Ubuntu on x86_64, using OpenSSH
• Tested: Ubuntu on WSL; aarch64 (Raspbian)
• Untested: OSX/BSD family
• Not currently supported: Windows

• You must have ssh access to the target machine.
• Install the qcp binary on both machines. It needs to be in your PATH on the remote machine.
• Run qcp --help-buffers and follow its instructions.

These can be found on the latest release.

• Debian/Ubuntu packages are provided.
• For other Linux x86_64: Use x86_64-unknown-linux-musl.tar.gz
• For other Linux aarch64: Use aarch64-unknown-linux-musl.tar.gz

The binaries are statically linked. Linux builds should work on all recent distributions, as long as you have selected the correct CPU architecture.

Prerequisite: You need to have capnpc installed. Your distribution likely packages this, or see https://capnproto.org/.

You can install the package from source using cargo:

cargo install --locked qcp

• Install the rustup tool via your package manager, or see Rust installation
• rustup toolchain install stable
• Proceed as above

The basic syntax is the same as scp or rcp.

qcp [OPTIONS] <SOURCE> <DESTINATION>

The program has a comprehensive help message, accessed via qcp -h (brief) or qcp --help (long form).

For example:

$ qcp my-server:/tmp/testfile /tmp/
⠂ Transferring data                                                           2.1MB/s (last 1s)
testfile ████████████████████████████████████░░░░░░░░░░░░░░░░░░░░░░░░ 1s @ 6.71 MB/s [10.49 MB]

The program uses the ssh binary on your system to connect to the target machine. ssh will check the remote host key and prompt you for a password or passphrase in the usual way.

By default qcp is tuned for a 100Mbit connection, with 300ms round-trip time to the target server.

Various network tuning options are available.

For example, if you have 300Mbit/s (37.5MB/s) download and 100Mbit/s (12.5MB/s) upload, you might use these options:

qcp my-server:/tmp/testfile /tmp/ --rx 37M --tx 12M

Performance tuning can be a tricky subject. See the performance documentation.

The brief version:

1. We ssh to the remote machine and run qcp --server there
2. Both sides generate a TLS key and exchange self-signed certs over the ssh pipe between them
3. We use those certs to set up a QUIC session between the two
4. We transfer files over QUIC

The protocol documentation contains more detail and a discussion of its security properties.

The initial release is made under the GNU Affero General Public License.

Feel free to report bugs via the bug tracker.

I'd particularly welcome performance reports from BSD/OSX users as that's not a platform I use regularly.

While suggestions and feature requests are welcome, please be aware that I mostly work on this project in my own time.

If you find this software useful and would like to say thank you, please consider buying me a coffee or ko-fi. Github sponsorship is also available.

If you're a business and need a formal invoice for your accountant, my freelancing company can issue the paperwork. For this, and any other commercial enquiries (alternative licensing, support, etc) please get in touch, to [email protected].

Please also consider supporting the galaxy of projects this work builds upon. Most notably, Quinn is a pure-Rust implementation of the QUIC protocol, without which qcp simply wouldn't exist in its current form.

Some ideas for the future, in no particular order:

• A local config mechanism, so you don't have to type out the network parameters every time
• Support for copying multiple files (e.g. shell globs or scp -r)
• Windows native support, at least for client mode
• Firewall/NAT traversal
• Interactive file transfer (akin to ftp)
• Smart file copy using the rsync protocol or similar (send only the sections you need to)
• Graphical interface for ftp mode
• Review the protocol and perhaps pivot to using capnp RPC
• Bind a daemon to a fixed port, for better firewall/NAT traversal properties but at the cost of having to implement user authentication.
• The same thing we do every night, Pinky. We try to take over the world!