Encryption works by encoding the text of a message with a key. In traditional encryption systems, the same key was used for both encoding and decoding. In the new public key or asymmetric encryption systems, keys come in pairs: one key is used for encoding and another for decoding. In this system everyone owns a unique pair of keys. One of the keys, called the public key, is widely distributed and used for encoding messages. The other key, called the private key, is a closely held secret used to decrypt incoming message. Under this system, a person who needs to send a message to a second person can encrypt the message with that person's public key. The message can only be decrypted by the owner of the secret private key, making it safe from interception. This system can also be used to create unforgettable digital signatures.

Most practical implementations of secure Internet encryption actually combine the traditional symmetric and the new asymmetric schemes. Public key encryption is used to negotiate a secret symmetric key that is then used to encrypt the actual data.

Because commercial ventures have a critical need for secure transmission on the Web, there is very active interest in developing schemes for encrypting the data that passes between browser and server.

• Order forms with credit card information
• Financial information
• Confidential information

This means that you are using an older browser such as Netscape 3.x and the Certificate Authentication which is built into the browser has expired. You may still be able to process your order in a secure manner, however you will receive an erroneous error message until you have made an update.

People running 3.x generation browsers can upgrade their security to the same level as that supported by 4.0 generation browsers. The process takes about 2 minutes and ensures that your browser works with the tens of thousands of Thawte certified secure servers out there, well into the next century. You only need to do this once, preferably before July 27 1998, for your browser to be updated permanently.

Netscape Navigator identifies a secure transaction in several ways:

Microsoft's Internet Explorer identifies a secure transaction by:

• The URL begins with https instead of http.
• On version 4.0 or higher a message box appears alerting the user that they are about to enter a secure location.
• On version 4.0 or higher a lock appears at the bottom of the browser ( ) .