Cryptography
Cryptography is study of sending message secretly.In modern times,it comes a branch of information technology,as the mathematical studies of information and specially ,its transmission from place to place.
One of its objective is to hiding the meaning of the message .It also contributes to computer science,central to technique used in computer and networks security for such things as access control and information confidentiality.
Cryptography is also used in many application we encountered in everyday life,the security PIN code in ATM cards and centres,in personal computer as a passwords,and electronic commerce-all are depend to cryptography.
Before modern age,Cryptography was concerned only to message confidentially.

