Free security software

encrypted instant messenger app (IM)

software tools for forensics analysis on volume and filesystem data

Java security framework that performs authentication, authorization, cryptography, and session management

chntpw or Offline Windows Password & Registry Editor is a software utility for resetting or blanking local passwords used by Windows NT operating systems on Linux. It does this by editing the SAM database where Windows stores password hashes.

VyOS is an open source network operating system Linux distribution based on Debian.

single sign-on protocol

OSSEC (Open Source HIDS SECurity) is a free, open-source host-based intrusion detection system (HIDS). It performs log analysis, integrity checking, Windows registry monitoring, rootkit detection, time-based alerting, and active response. It provides intrusion detection for most operating systems, including Linux, OpenBSD, FreeBSD, OS X, Solaris and Windows. OSSEC has a centralized, cross-platform architecture allowing multiple systems to be easily monitored and managed. OSSEC has a log analysis engine that is able to correlate and analyze logs from multiple devices and formats.

free and open-source Shadowsocks deployment tool

GoodbyeDPI is a free and open-source software tool for bypassing deep packet inspection (DPI) systems and Internet censorship. It was created by Russian developer ValdikSS in 2016 and is distributed under the Apache License via GitHub.

FreeS/WAN, for Free Secure Wide-Area Networking, was a free software project which implemented a reference version of the IPsec network security layer for Linux. The project goal of ubiquitous opportunistic encryption of Internet traffic was not realized, although it did contribute to general Internet encryption.

ClamTk is a free and open-source graphical interface for the ClamAV command-line antivirus software program for Linux desktop users. It provides both on-demand and scheduled scanning. The project was started by Dave Mauroni in February 2004. As of April 2024, the program is no longer maintained.

Decentraleyes is a free and open-source browser extension used for local content delivery network (CDN) emulation. Its primary task is to block connections to major CDNs such as Cloudflare and Google (for privacy and anti-tracking purposes) and serve popular web libraries (such as JQuery and AngularJS) locally on the user's machine. Decentraleyes is available for Microsoft Edge, Mozilla Firefox + Firefox ESR, Google Chrome, Pale Moon and Opera web browsers.

free software library implementing TLS

Linux distribution