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Cryptography is the art of disguising data so that only the intended recipient can see through that disguise. Cryptography is crucial to both privacy and security on the Internet

General Cryptography Links:

  • Cryptography FAQ
  • OpenSSH – Secure alternative to telnet or rlogin, encrypts all traffic to effectively eliminate eavesdropping, connection hijacking, and other network-level attacks. Also does sftp, a secure version of ftp.
  • Explanation of SSH
  • Rubberhose – Rubberhose transparently and deniably encrypts disk data, minimising the effectiveness of warrants, coersive interrogations and other compulsive mechanims, such as U.K RIP legislation.
  • m-o-o-t – In development, it will be a bootable CD with a suite of email, w/p, spreadsheet, graphics etc programs on the CD.  It will be secure against RIPA, Carnivore, the Australian and proposed Council of Europe and NZ laws regarding seizure of stored data, intercepted data, traffic data and access to plaintext/keys of encrypted data.
  • HushMail – Secure Web-based email system


PGP (short for Pretty Good Privacy) is the de facto standard program for secure email encryption on the Internet. Invented in 1990 by Phil Zimmerman, its public-key cryptography system enables people who have never met to secure transmitted messages against unauthorised reading and to add digital signatures to messages to guarantee their authenticity. The Gnu Privacy Guard GnuPG is a complete and free replacement for PGP.

PGP Links:


Steganography simply takes one piece of information and hides it within another. Data files (images, sounds recordings, even filesystems) contain unused or insignificant areas of data. Steganography takes advantage of these areas by replacing them with information (encrypted mail, for instance). The files can then be exchanged without anyone knowing what really lies inside them. For instance, an image of the space shuttle might contain a private letter to a friend or a recording of a short sentence might contain your company’s plans for a secret new product. Steganography can also be used to place a hidden “trademark” in images, music, and software, a technique referred to as watermarking.

Steganography Links:

  • mp3stego – Hides information in mp3 files during the compression process.
  • nicetext – Converts any file into pseudo-natural-language text
  • OutGuess – Hides information in PNM and JPEG image formats
  • Steghide – Hides information in bmp, wav and au files
  • StegFS – A Steganographic File System for Linux. Not only does it encrypt data, it also hides it such that it cannot be proved to be there.

Voice Encryption

Voice encryption programs offer the ability to have a real-time secure telephone conversation over the internet or through a direct modem-to-modem connection.

Voice Encryption Links:

  • Speak Freely – Encryption of voice with DES, Blowfish, IDEA, and/or a key file over TCP/IP networks (Unix only)
  • Nautilus – Encryption with DES, Blowfish, IDEA. Works over ordinary phone lines or TCP/IP networks (Unix & Windows)
  • PGPfone – Encrypt your phone calls, works over ordinary phone lines and TCP/IP or appletalk networks (Windows & Mac)
Last modified: 21 July 2012