Cryptography Essay

Information security plays a central role in the deployment of modern communication systems. The most important objectives of information security are authentication, confidentiality, data integrity and non-repudiation. Confidentiality ensures that information is accessible only to those authorized to have access. Authentication is the process proving the identity that assures the communicating entity is the one that it claimed to be, this means that the user or the system can prove their own identities to other parties who don’t have personal knowledge of their identities. Data integrity ensures that the received information has not been altered in any way from its original form. Data integrity safeguards the accuracy and completeness of information and processing methods.

The word cryptography comes from the Greek word "Kryptos", that means hidden, and "Graphikos" which means writing. Cryptography or communication by using secret code was used by the Egyptians some 4000 years ago. However, the science of cryptography was initiated by Arabs since 600s. Cryptography becomes vital in the twentieth century where it played a crucial role in the World War I and II. Cryptographic technique is an effective method for protecting many private and public data transported in the network of global information communication. It is the process of changing information such as e-mail, banking data, and other confidential information, into an unreadable form that only the person intended to receive it can understand the information. There are two types of cryptographic schemes in use today: private key or secret key (also known as symmetric) cryptography and public key (also known as asymmetric) cryptography. Symmetric key cryptography uses the same key for encryption and decryption. Another type of encryption method, asymmetric or public key cryptography uses different keys to encrypt and