ABSTRACT

The importance of protecting the secrecy of sensitive messages has been realized by people since ancient times. Secret writing has been an established problem and this field was named cryptology, which was mainly concerned with military and diplomatic applications for a long time. By using the strong technique of information, the storage and transmission of information become cheap and simple in modern times. A huge amount of information is transformed in a way that almost anyone may access it. A lot of new problems related to cryptology appear. For example, an enemy might not only have the means to read transmitted messages, but could actually change them, or the enemy could produce and send a false message to the receiver and hope that this would initiate some action.