Secure One‑Click File Transfer Between PCs Using Croc

Tool Features and Advantages

Relay‑based transfer works between any two computers

End‑to‑end encryption using PAKE

Cross‑platform support for Windows, Linux, and macOS

Multiple files or entire directories can be sent in one command

Supports resumable transfers

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

Prefers IPv6, falls back to IPv4

Can operate through a SOCKS5 proxy

Croc project URL: https://github.com/schollz/croc

Usage

To send a file, run the following command on the sending computer: $ croc send file.txt The tool generates a secret code that the receiver must use:

$ 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

On the receiving computer, execute the displayed command:

$ 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 sending files through your own relay, add the --relay flag to the command:

$ 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

The Croc tool emphasizes simplicity, security, and speed, making point‑to‑point file transfers easy across Windows, macOS, and Linux. With a single CLI command and optional self‑hosted relay, users can share files quickly without complex setup.