APPENDIX DIntroduction to Cryptography
Cryptology is derived from the Greek words kryptos, which means "hidden," and grafein, which means "to write." Through history, cryptography has meant the process of concealing the contents of a message from all except those who know the key. Cryptography is used to protect e-mail messages, credit card information, and corporate data. Cryptography has been used for centuries to hide messages sent through means where they might be intercepted, such as the Internet.
A wide variety of cryptographic techniques are in use with computers. They are typically provided for one of two reasons: to protect data on the computer or to protect data as it is being transferred.
Most cryptographic techniques for submitting ...