Cryptography is the process, in which the information is encrypted in a form so that the actual information cannot be read the person who does not have the mathematical "key" to decrypt it. Two methods are used for cryptography. One is "same-key cryptography" and other is "public-key cryptography". In case of "same-key" cryptography, the key used to encrypt and decrypt the message is same. In case of "public-key" cryptography, different keys are used for encryption and decryption. This method is more secure than same-key cryptography.