The Need for Security
Several types of Internet-related transactions require a high level of security. These include financial transactions, such as banking operations and electronic commerce, but also any exchange of sensitive information, such as medical records and corporate documents. Secure transactions over the Internet require three main elements:
Confidentiality. If you are transmitting or accessing sensitive information such as your credit card number or your personal medical history, you certainly don't want a stranger to get hold of it.
Integrity. Transmitted information must be protected from external manipulationif you place an order online to buy 100 shares of stock, you don't want anyone to intercept the message, and change it to an order to buy 1000 shares.
Authentication. You need to trust the organization or individual you are communicating with is who they say they are.