Encryption for Those in Need

Encryption 

Lately, we've been hearing of peccadillos and possibly serious and illegal uses of email by high level national figures, e.g. General David Petraeus and EPA Administrator Lisa Jackson. In most cases, the messages have been read by unwanted persons, much to the unhappiness and ruination of the senders. If you really want your messages to be secure, you need to encrypt them, not with a secret code ring, but with secure but simple to use software. It is free and available.

Creating encrypted messages. If you must or just want to send encrypted messages, you want something simple to use. There is an easy and secure method. We'll show you how to use it. It is based on what was once considered the "unbreakable" Vigenere cipher. While this cipher is no longer unbreakable, breaking it would require (i) a whole lot of text to work with and (ii) a very powerful computing apparatus. Indeed, the decryption software would almost need to know the type kind of code used. Nonetheless, for most of us without access to high level decryption software such as possessed by the National Security Administration (NSA) deployed on the most powerful computers, the Vigenere cipher is essentially unbreakable.

Encrypting your messages to a friend:

1. What you need is a passcode that you and your firend will share. For example, it could be "secret" or "alphabeta" or "abcghxy, all lower case alphabetic characters. Use different passcodes for different people. It can be a maximum of nine characters, all lower case. A very short passcode makes craking it somewhat easier.
2. Now go to http://disted6.math.tamu.edu/techtools/flash/crypto/Vigenere.html.
3. Enter your passcode in the box provided.
4. Enter your message into the provided (left) box. Press the "Encrypt" button. Your encrypted message will appear in the next (right) box. Copy this message into your e-mailer, and send.
5. Your friend will receive the message to copy and paste into the decrypt (right) box at the same URL. When he/she has enters the same password and presses the "Decrypt" button, the decrypted message will appear in the left box.
6. Note: The code will not work with the iPad as iPad's are generally not Flash enabled.  The encryption program is written in Flash

How secure it this? There are three issues, (a) the security of the encryption, and (b) whether the URL maintains your security, and (c) will your friend keep confidential your message(s). First, the security of the encryption is as secure as described above - very difficult to decrypt. Second, no matter what "hidden" technology is at the other end - and there is actually none - you and your recipient are completely anonymous because you work with your own mailer. The given Vigenere code at URL merely encrypts and decrypts the message. If your are still skeptical, you can download the entire URL package including the Flash encryption script and run it from your own computer. As to the last issue, (c), that is beyond the purview of technology. That is the true weakness of all encryption methods.

So, now you have fully functional encryption software for your personal use. Enjoy.

Notes on the Vigenere cipher.
The next level of encryption , beyond the Caesar cipher (passcode is one character), in difficulty to crack is the Vigenère (pronounced "veedj-ih-nair") cipher, named after the Frenchman Blaise de Vigenère. It was first published in 1568. It is an example of a polyalphabetic cypher, meaning it uses several alphabetic characters to form the encryption. Instead of shifting the alphabet by a fixed length as does the Caesar cipher, it shifts by the numerical values* of a passcode successively through the message. So if the passcode is "dog," the first letter is shifted by "d" or four letters, the second by "o" or fourteen characters, the third by "g" or six characters, the fourth by "d" again, and so on repeating the passcode letters. If the shift goes beyond the letter "z," there is a wrap-around to the beginning of the alphabet. In this version of the Vigenere cipher, the lower case, upper case and numbers are all shifted within their context. Caps stay caps, numbers stay numbers, and likewise for small letters. This makes cracking the code using frequency counts far more difficult. Indeed, it was once considered the "unbreakable cypher." Nowadays this code is considered not overly difficult to crack (for a computer).

* Lower-case shifting values. The bottom row tells how many places should be shifted for a given letter of the passcode.

More advanced encryption yet. Assuming you require totally unbreakable codes, you should consider PGP (Pretty Good Privacy). It uses a far more advanced encryption algorithm. It is a bit more difficult to use. See http://en.wikipedia.org/wiki/Pretty_Good_Privacy



Final note: Using permutations, etc, of the passcode to extend the passcode, this simple script could be made to be seriously unbreakable.  Commercial versions are available, with individual options.