Best Linux Free Open-Source Security Software

Private, end-to-end encrypted messaging.

A note-taking app with a focus on security and simplicity

Free backup software to store encrypted backups online

A simple, fast, and secure note-taking app

A secure password manager for teams

Deduplicating backup solution

Fast, secure, efficient backup program

Network-wide ad blocking DNS server for homes and small businesses

Fast and secure backup and versioning for files and directories

Network-wide ads & trackers blocking DNS server

Secure, fast file transfers from the command line

Lightweight Intranet Penetration Proxy Server

Interactive, scriptable man‑in‑the‑middle proxy for HTTP, HTTPS and WebSocket traffic

Cross-platform password manager compatible with Keepass 2.x

General purpose TLS and crypto library

Open-source antivirus engine for detecting malware across platforms

High-performance reverse proxy for NAT traversal

Secure and fast microVMs for serverless computing

An open platform for various uses

Secure dotenv for developers

Interactive application firewall for GNU/Linux

A modern, secure password manager

A fast, secure, minimalist note‑taking app for students and freelancers

Secure, private budgeting for individuals and households