ABSTRACT
This entry is an overview of modern cryptography. It begins with cypher classification, and presents the concepts of symmetric and asymmetric key cryptosystems. The entry details inner compositions of block ciphers, particularly the AES (Advanced Encryption System) algorithm, and background theory is discussed. The entry develops the underlying mathematics of the increasingly popular asymmetric key algorithm, the Elliptic Curve Cryptosystems (ECC). Concepts are discussed for efficient implementations of the ECC scalar multiplication, such as LSB first and MSB first algorithms, and the Montgomery ladder.
