By the turn of the century, commercial transactions on the Internet are expected to total hundreds of billions of dollars a year. This level of activity could not be supported without cryptographic security. It has been said that one is safer using a credit card over the Internet than within a store or restaurant. It requires much more work to seize credit card numbers over computer networks than it does to simply walk by a table in a restaurant and lay hold of a credit card receipt. These levels of security, though not yet widely used, give the means to strengthen the foundation with which e -commerce can grow.
People use e -mail to conduct personal and business matters on a daily basis.
E -mail has no physical form and may exist electronically in more than one place at a time. This poses a potential problem as it increases the opportunity for an eavesdropper to get a hold of the transmission. Encryption protects e -mail by rendering it very difficult to read by any unintended party. Digital signatures can also be used to authenticate the origin and the content of an e -mail message. In some cases cryptography allows you to have more confidence in your electronic transactions than you do in real life transactions.