Cryptography or cryptology comes from Greek word kryptos meaning "Hidden secret" and graphein meaning "Writing". Cryptography is the practice and study of hiding information. Cryptography helps provide accountability, fairness, accuracy and confidentiality. It can prevent fraud in electronic commerce and assure the validity of financial transactions. The art or science encompassing the principles and methods of transforming an intelligible message into one that is unintelligible, and then retransforming that message back to its original form. Cryptography can be defined as the conversion of data into a scrambled code that can be deciphered and sent across a public or private network.