Referring to Appendix 9A, distinguish among data encryption, public key cryptography, and digital signatures.

Appendix 9A Public Key Cryptography and Digital Signatures As we noted in Chapter 8, a conventional data encryption procedure involves a single key that is used both by the sender to encrypt the message and by the receiver to decrypt it. A major drawback to single key systems is that you need a different key for each trading partner. Another disadvantage is that the key itself has to be transmitted by secure chan- nels. If the key is not kept secret, the security of the entire system is compromised. Pub- lic key cryptography helps to solve this problem by employing a pair of matched keys for each system user, one private (i.e., known only to the party who possesses it) and one