ABSTRACT
The most fundamental question about Internet economics involves the source of revenue for the core of the Internet. The most common form of e-commerce transaction consists of a retail purchase from a catalog. To enable e-commerce, the company advertising an item for sale provides a way for the user to purchase the item. However, before a browser can verify a digital signature and know which web sites can be trusted, the browser must be absolutely certain it knows the sender's public key. Instead, trusted companies exist that register public keys and provide them as needed. After the company provides the public key, the browser uses the key to verify authenticity of the original message. Many groups have proposed an alternative known as digital money or digital cash. Several schemes have been proposed; the easiest to understand views digital cash as a form of debit card. Certificates allow a browser to obtain the public key of a company automatically and safely.
