Encryption

Encrytion is the process of taking all the data that one computer is sending to another and encoding it into a form that only the other computer will be able to decode. Most computer encryption systems belong in one of two categories:

•  Symmetric-key encryption
•  Public-key encryption

In symmetric-key encryption, each computer has a secret key (code) that it can use to encrypt a packet of information before it is sent over the network to another computer. Symmetric-key requires that you know which computers will be talking to each other so you can install the key on each one. Say you create a message for your friend and you tell your friend that each letter is substituted with the letter three down from it in the alphabet. So now A becomes D and B becomes E. Now, your friend would understand the message that you sent but if some else looks at it they will think it is nonsense.

Public-key encryption uses a combination of a private key and a public key. The private key is known only to your computer, while the public key is given by your computer to any computer that wants to communicate securely with it. To decode an encrypted message, a computer must use the public key, provided by the originating computer, and its own private key.