Cryptography

Contents

Evolution of cryptography

Theory

Encryption and decryption

Data Encryption Standard

Public key cryptography

Symmetric key Cryptography

The word ‘cryptography’ in Greek means ”secret writing”. Cryptography is the study of message secrecy.In modern times,cryptography is considered to be a branch of math and computer scienc and is affiliated with information theory,computer security,engineering.Cryptography is used in applications present in technologically advanced societies; examples include the security of ATM cards, computer paswords, and electronic commerce, which all depend on cryptography.