Reusable code libraries and increasing competition among Web site providers will continue to bring down costs even as the Web sites themselves become more sophisticated. Demand for goods made available through electronic commerce is driven by many sources. Today, electronic transactions are mainly conducted between financial institutions, some retailers, and a relatively small but growing number of consumers. According to recent surveys, the products most widely purchased over the Internet are books and publications followed by software and electronics. A protocol is nothing more than a common set of semantics used to communicate information between two or more programs or devices.
Protocols rule each level of a transaction.
Additional protocol layers allow users to interact with Web browsers and databases and provide a framework for coordination between distributed applications. Authentication of both the customer and service provider establishes their identities and ensures that both are who they say they are. The most favored approach for this is to exchange a set of data which had been encrypted through the use of RSA's public-key cryptography. The private key is known only to its owner and used by its owner to encrypt messages and provide a digital signature. The associated public key is known to everyone else and used to decrypt messages and authenticate the sender of the message.