Cryptography is the practice and study of hiding information.
Modern cryptography intersects the disciplines of mathematics, computer science, and engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce.Cryptanalysis is the complementary science concerned with the methods to defeat
these techniques. Cryptology is the study of cryptography and cryptanaylsis. Key fea-
tures of information security information include confidentiality or privacy, data integrity,
authentication, and nonrepudiation.
Each of these aspects of message security can addressed by standard methods in cryptog-
raphy. Besides exchange of messages, tools from cryptography can be applied to sharing
an access key between multiple parties so that no one person can gain access to a vault by
any two of them can. Another role is in the design of electronic forms of cash.