CRYPTOGRAPHY
INTRODUCTION
Cryptography is the study of hidden formation and is
considered as a branch of mathematics and computer science. It is
the study of methods to send and receive secret message. In general
we have a sender who is trying to send a message to a receiver. We
are successful if the sender is able to communicate a message to the
receiver without the adversary learning what the message was.
Cryptography is the art and science of encryption. Now a days
it is much broader, covering digital signatures and many more
security functions to build good cryptographic systems.
For thousands of years people have searched for ways to send
messages secretly. There is a story that, in ancient times, a king
needed to send a secret message to his general in battle. The king
took a servant, shaved his head and wrote the message on his head.
He waited for the servant’s hair to grow back and then sent the
servant to the general. The general then shaved the servant’s head
and read the message. If the enemy had captured the servant, they
presumably would not have known to shave his head, and the
message would have been safe.
Cryptography has remained important over the centuries, used
mainly for military and diplomatic communications. Recently with
the
Advent of the internet and electronic commerce, cryptography has
become vital for the functioning of the global economy and is
something that is used by millions of people on daily basis.
