Ark: Displaying, decompression (Linux)  
  Bzip2: Compression (Linux, Mac, Win)
  Cryptmount: Encrypt Files (Linux)
  DAR: Disk ARchive (Linux, Win)
  File Roller: Archive Manager (Linux)
  Gzip: Compression (Linux, Mac, Win)
  PeaZip: Free Archiver (Linux, Mac, Win)
  Tar: Archive App (Linux, Mac)
  Unarchiver: Compression (Mac) 
  7-Zip File-Compression (Win)
  7 Best Compression Tools (Linux, Mac, Win)
Internet Encryption:
  EnigMail: Email Security (Linux, Mac, Win)
  HTTPS: Encrypt the Web (Linux, Mac, Win)
  Mailvelope: Browser (Linux, Mac, Win)
  Mymail-Crypt for Gmail (Linux, Mac, Win)
  Tor: Browser, Anonimity (Linux, Mac, Win)
  TorBirdy: Email & Tor (Linux, Mac, Win)
  Whispers, TextSecure, (Linux)
Password Managers:
  Encryptr (Linux, Mac, Win)
  Keepass (Linux, Mac, Win)
  KeePassX & KeePassXC (Linux, Mac, Win)
  Keeweb (Linux, Mac, Win)
  LastPass (Linux, Mac, Win)
  PasswordGorilla (Linux, Mac, Win)
  UPM (Linux, Mac, Win)
Security & Anti-Virus:
  Amavis: Mail Scanner (Linux, Mac, Win)
  AxE: Security Tool (Win)
  Axcript: Encryption (Win)
  AVG: Anti-Virus (Linux, Win)
  Bastille-Linux: Security (Linux, Mac)
Security (Cont.):
  BoxCryptor: Cloud Storage (Win)
  Brutelock: Stop Attackers (Linux)
  Chkrootkit: System Integrity (Linux)
  ClamAV: AntiVirus (Linux)
  ClamWin AntiVirus (Win)
  ClamXav Antivirus (Mac)
  Collax: Network Security (Linux)
  Cryptmount: Encrypted Files (Linux)
  DansGuardian: WebFilter (Linux, Mac)
  DenyHosts: Security (Linux, Mac) 

  Endian: Firewall Community (Linux)
  Firestarter Firewall (Linux)
GnuPG: Privacy Guard (Linux, Mac, Win)
Gpg4win: Security Desktop (Win
  Guardog Firewall (Linux)
  Hping: TCP/IP Analyzer (Linux, Mac, Win)
  Idemix: Identity Security (Linux, Win)

  IPFilter: TCP/IP Firewall (Linux)
  John The Ripper: Passwd Cracker (Linux, Mac)
Kismet: Wireless Detector (Linux, Mac, Win)
  Linux Security Tools: Top 100 (Linux, Mac, Win)
  Malwarebytes: Anti-Virus (Mac, Win)
  Mail Scanner: Anti-Virus (Linux)

  MacFure: 3rd-Party Systems (Mac)

  MacTrash: Clean it (Mac)
  Moblock: Block Connections (Linux)
  MoonSecure: Anit-Virus (Windows)
  Nagios: Virus for Enterprise (Linux, Win)
  Nessus Virus scanner (Linux, Mac, Win) 
Nmap: Network Scanner (Linux, Mac,Win)
NuFW: Firewall (Linux)
  OpenDNS: Secure Network (Linux, Mac, Win)
OpenSSL: Secure Sockets (Linux)
Security (Cont.)
  OpenSSH: Connect (Linux, Mac, Win)
  OpenVas Nessus Fork (Linux, Mac, Win)
  OSSEC: Intrusion Detectionstem (Linux, Win)
  P3Scan (Linux)
  Prey: Anti Theft (Linux, Mac, Win)
  Proxmox: Anti Spam (Linux)
  Putty: Telnet/SSH Client (Linux)
  RFXN: Networks, Firewall (Linux)
  RKHunter: Malware Scan (Linux)
  Sardu: Antivirus Rescue Utility (Linux, Win)
  Seahorse: Encryption Made Easy (Linux)
  SecretSync: Encryptor (Linux, Mac, Win)
  Security: Best 80 Programs (Linux, Mac, Win)
  SmoothWall Firewall (Linux)
  Snort: Intrution Prevention (Linux, Win)
  SpamAssassin (Linux, Mac, Win)
  SpiderOak: (Linux, Mac, Win)
  Spybot Search & Destroy (Win)
  TCPDUMP Network Debugging (Linux)
  TrueCrypt: Encryption (Linux, Mac Win)
  Viralator: Anti-virus (Linux)
  Virus: Anti-virus (Linux, Mac, Win)
  Vuurmuur: Firewall (Linux, Mac, Win)
  Wicd Encryption (Linux, Win)
  WireShark: Packet Sniffer (Linux, Mac, Win)
  Zfone: Email Encrypt (Linux, Mac, Win)
  Zoneminder: Home Surveillance (Linux)
  5 Best Content Filtering Tools (Linux)
  40 Tools for Privacy (Linux, Mac, Win)
  80 Bes Security Apps (Linux, Mac, Win)