Cryptography (a.k.a. cryptology) is the practice of techniques for secure (confidential or private) communication in the presence of third parties, referred to as adversaries in this context, because the latter may intercept and compromise (usually by decoding or deciphering) the secure communication for nefarious purposes. In general practice, cryptography is concerned about designing and analyzing secure communication protocols that thwart adversaries. Cryptographic techniques tend to be multi-disciplinary, and involve the disciplines of mathematics, computer science and electrical engineering. Common applications of cryptography include computer passwords, ATM cards, smart credit cards, and electronic commerce transactions.
Usage Note: The term cryptography is sometimes conflated with the term cryptology, where the former is the practical application of secure communication techniques, whereas the latter is the formal study of these techniques.