How Does It Work?
There are types of encryption that are used for specific uses and work in different ways. One is public key encryption. It uses mathematical asymmetrical algorithms with a computer program to create two keys. One key is public and used to encrypt a message. The second key is private, and used by the recipient to decrypt the message. This method is commonly used with the Pretty Good Privacy (PGP) and the Transport Security Layer (TSL) technique to transmit encrypted information over the Internet.
Another method is secret key encryption. Using symmetrical algorithms, a single key is made from a combination of numbers or letters. Both the sender and receiver have the same key to encrypt and decrypt the message. The simplest variation of this method is the substitution cipher. Used for text messages, it simply switches letters to different ones further down the alphabet. The idea of this originally came from Julius Cesar. A common substitution cipher used today is the ROT13, which switches letters of a message 13 letters further down the alphabet.
Secret key encryption has been used to protect computer hard drives, blocking “Pay per View" transmissions on cable TV and hiding movie/book spoilers on the Internet. However, it is not considered the most secure method since knowledge of the key can be compromised if steps are not taken to prevent it from being discovered.
For higher security encryption, variations of the public and secret key encryption types have been created. The current United States standard for encryption methods (as of 2002), called the Advanced Encryption Standard (AES) uses a combination of a substitution cipher, matrix multiplication and the exclusive XOR method to prepare data and keys for secure transmissions.