croc

README

croc is a tool that allows any two computers to simply and securely transfer files and folders. AFAIK, croc is the only CLI file-transfer tool does all of the following:

• allows any two computers to transfer data (using a relay)
• provides end-to-end encryption (using PAKE)
• enables easy cross-platform transfers (Windows, Linux, Mac)
• allows multiple file transfers
• allows resuming transfers that are interrupted
• local server or port-forwarding not needed
• faster than wormhole, rsync, scp through compression and multiplexing (speedups 1.5x to 4x)

For more information about croc, see my blog post.

Install

Download the latest release for your system, or install a release from the command-line:

$ curl https://getcroc.schollz.com | bash

On macOS you can install the latest release with Homebrew:

$ brew install schollz/tap/croc

On Windows you can install the latest release with Scoop:

$ scoop install croc

On Unix you can install the latest release with Nix:

$ nix-env -i croc

On Arch Linux you can install the latest release with pacman:

$ pacman -S croc

Or, you can install Go and build from source (requires Go 1.12+):

$ GO111MODULE=on go get -v github.com/schollz/croc/v6

Usage

To send a file, simply do:

$ croc send [file(s)-or-folder]
Sending 'file-or-folder' (X MB)
Code is: code-phrase

Then to receive the file (or folder) on another computer, you can just do

$ croc code-phrase

The code phrase is used to establish password-authenticated key agreement (PAKE) which generates a secret key for the sender and recipient to use for end-to-end encryption.

There are a number of configurable options (see --help). A set of options (like custom relay, ports, and code phrase) can be set using --remember.

Custom code phrase

You can send with your own code phrase (must be more than 4 characters).

$ croc send --code [code-phrase] [file(s)-or-folder]

Use pipes - stdin and stdout

You can pipe to croc:

$ cat [filename] | croc send

In this case croc will automatically use the stdin data and send and assign a filename like "croc-stdin-123456789". To receive to stdout at you can always just use the --yes will automatically approve the transfer and pipe it out to stdout.

$ croc --yes [code-phrase] > out

All of the other text printed to the console is going to stderr so it will not interfere with the message going to stdout.

Self-host relay

The relay is needed to staple the parallel incoming and outgoing connections. By default, croc uses a public relay but you can also run your own relay:

$ croc relay

Make sure to open up TCP ports (see croc relay --help for which ports to open).

You can send files using your relay by entering --relay to change the relay that you are using if you want to custom host your own.

$ croc --relay "myrelay.example.com:9009" send [filename]

If it's easier you can also run a relay with Docker:

$ docker run -d -p 9009:9009 -p 9010:9010 -p 9011:9011 -p 9012:9012 -p 9013:9013 schollz/croc

License

MIT

Acknowledgements

croc has been through many iterations, and I am awed by all the great contributions! If you feel like contributing, in any way, by all means you can send an Issue, a PR, ask a question, or tweet me (@yakczar).

Thanks @warner for the idea, @tscholl2 for the encryption gists, @skorokithakis for code on proxying two connections. Finally thanks for making pull requests @maximbaz, @meyermarcel, @Girbons, @techtide, @heymatthew, @Lunsford94, @lummie, @jesuiscamille, @threefjord, @marcossegovia, @csleong98, @afotescu, @callmefever, @El-JojA, @anatolyyyyyy, @goggle, @smileboywtu, @nicolashardy!