Secure Fast Peer-to-Peer File Transfer with Croc: Install, Use, and Customize

Transferring files between two computers can be done with many methods such as FTP or SSH, but they often require complex setup. Croc, a Go‑based utility, offers a simple, secure, and fast solution for point‑to‑point file transfer.

Features and Advantages

Uses a relay to enable any two computers to exchange files

End‑to‑end encryption with PAKE

Cross‑platform support (Windows, Linux, macOS)

Can send multiple files or entire directories

Supports resumable transfers

No need to set up your own server or use port‑forwarding

Prefers IPv6, falls back to IPv4

Can work through a SOCKS5 proxy

Installation

Download the latest version for your system and install via the command line: $ curl https://getcroc.schollz.com | bash On macOS you can also install with Homebrew:

$ brew install croc

Usage

One sender and one receiver are required. The diagram below illustrates the setup:

Send a file with a single command:

$ croc send ~/Downloads/data.csv
Sending 'data.csv' (632.9 kB)
Code is: cabinet-rodeo-mayday
On the other computer run:

croc cabinet-rodeo-mayday

The receiver runs the generated code to accept the file:

$ croc cabinet-rodeo-mayday
Accept 'data.csv' (632.9 kB)? (y/n) y
Receiving (<-111.243.108.9:51032)

You can also specify a custom secret code:

$ croc send --code appleboy ~/Downloads/data.csv

Running Your Own Relay Server

Croc uses a default relay server (croc.schollz.com). To deploy a private relay, run:

$ croc relay
[info] 2021/02/16 11:38:59 starting croc relay version v8.6.7-05640cd
[info] 2021/02/16 11:38:59 starting TCP server on 9010
[info] 2021/02/16 11:38:59 starting TCP server on 9012
[info] 2021/02/16 11:38:59 starting TCP server on 9009
[info] 2021/02/16 11:38:59 starting TCP server on 9013
[info] 2021/02/16 11:38:59 starting TCP server on 9011

You can bind the relay to a specific port:

$ croc relay --ports 3001
[info] 2021/02/16 11:39:22 starting croc relay version v8.6.7-05640cd
[info] 2021/02/16 11:39:22 starting TCP server on 3001

When transferring files, point Croc to your custom relay:

$ croc --relay 127.0.0.1:3001 send ~/Downloads/data.csv
Sending 'data.csv' (632.9 kB)
Code is: saddle-origin-horizon
On the other computer run:

croc --relay 127.0.0.1:3001 saddle-origin-horizon

Conclusion

Croc emphasizes three core strengths: simple , secure , and fast . It enables effortless peer‑to‑peer file transfers across any platform with a single command, making it a practical alternative to traditional FTP or SCP solutions.

Original source: https://blog.wu-boy.com/2021/02/share-files-between-two-computer-using-croc-tool/