croc – Simple Secure File Transfer

croc is a tool that allows any two computers to simply and securely transfer files and folders. It uses relay servers and password-authenticated key exchange (PAKE) to establish end-to-end encryption without requiring complex setup or pre-shared keys between sender and receiver.

Unlike traditional tools that require SSH setup or email attachments, croc generates a simple code phrase that recipients use to receive files. This makes it perfect for quick, secure transfers between colleagues, friends, or your own devices without any prior configuration.

Key Features

• End-to-End Encryption – PAKE for secure key exchange
• No Setup Required – Works immediately between any computers
• Resume Transfers – Continue interrupted transfers
• Multiple Files – Send files and folders
• Cross-Platform – Linux, Windows, macOS, and mobile
• Self-Hostable – Run your own relay server

Installation

# Install via curl
curl https://getcroc.schollz.com | bash

# Or with package manager
sudo apt install croc    # Debian/Ubuntu (if available)

# Or with Go
go install github.com/schollz/croc/v9@latest

Basic Usage

# Send a file
croc send file.txt
# Outputs: Code is: 1234-secret-words

# Receive the file (on another computer)
croc 1234-secret-words

# Send with custom code
croc send --code mycode file.txt

# Send multiple files
croc send file1.txt file2.txt folder/

# Self-host relay
croc relay

Use Cases

• Quick File Sharing – Send files to colleagues instantly
• Cross-Network Transfer – Works through NAT and firewalls
• Secure Sharing – End-to-end encrypted transfers
• Large Files – No file size limits like email

Download croc