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. For example, signing documents in real life still leaves one vulnerable to the following scenario. After signing your will, agreeing to what is put forth in the document, someone can change that document and your signature is still attached. Cable TV is set up so people can watch only the channels they pay for.