Encryption and Decryption

By Walton Dell
Last Updated: June 25, 2006

Encryption is the manipulation of data, based on a password (also known as a key), for security purposes. Once your data has been encrypted, a person can not make sense of your data without knowing the password (or figuring it out). For example, if we take HAL and add 1 to each of the letters, we get IBM (betcha didn't know that!). In this case, the password is simply "1". If we use "123456" as our password, then we add 1 to the first letter, 2 to the second, ..., 6 to the sixth, then we start over at 1 and add 1 to the seventh letter. Now our encrypted data is, "ICN". To decrypt, the password "123456" is "subtracted" from our data.

Sophisticated software can make intelligent guesses of the password to decrypt data. One easy way is with a database of common passwords. A more difficult way is by analyzing the encrypted data. If you know the decrypted data starts with 20 spaces, then you subtract 20 spaces from the data, you will get "12345612345612345612" if the password was "123456". A longer password makes it more difficult to decrypt the data without knowing the password.

Another way security could be breached is if someone were to tap into a transmission. The Internet is a worldwide network of computers. If you were to send unencrypted data across the Internet, someone may be able to view the data if they operate a part of the Internet your data must pass through. This is why you should not send credit card information over the Internet unless you use "Secure mode". Each web browser has its own way of letting you know that it is in secure mode. Check the help system of your web browser for more information.


Copyright 1997-2006 by Walton Dell

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