Cryptography:

The use of a secret code over a public network, the original text is converted into code with an encryption algorithm, which uses a binary number key to "lock" the data. When the message is received, the encrypted code is decoded or "unlocked" and turned back into the original text.

Cryptography can be done in one of two ways: secret key or public key. The secret key uses the DES standard. Because both the sender and recipient use the same key to lock and unlock the message, it’s faster but less secure. The second way is public key cryptography, such as RSA, which combines the use of a private and public key. The recipient has both a private and public key, and senders use the public key to send a message. The recipient, however, uses the tightly held private key to decode the message. Since the recipient is the only one with the private key, and since the key is never sent over the Internet, this message is more secure.