Cryptography, or cryptology (from Ancient Greek: κρυπτÏŒς, romanized: kryptós "hidden, secret"; and γράφειν graphein, "to write", or -λογία -logia, "study", respectively), is that the practice and study of techniques for secure communication within the presence of third parties called adversaries. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the general public from reading private messages; various aspects in information security like data confidentiality, data integrity, authentication, and non-repudiation are central to modern cryptography. Modern cryptography exists at the intersection of the disciplines of mathematics, computing , EE , communication science, and physics. Applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications.