presented by:
R. Vijaya Kumar
V. Austin Paul

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ABSTRACT
Many organizations are working hard to secure themselves from the growing threats of message hacking through various trends in cryptography. Yet the headlines are dominated with the latest news of message passing disaster more frequently than any time before. This document intends to review this problem and propose several possible solutions. The cryptographic industry has been responding to these threats with ever-quicker responses to the rapid onslaught of malicious techniques, while corporations establish strict cryptographic techniques.
Placing an organizations cryptographic technique at the desktop level is like closing all the doors in a house…..while leaving windows and other entry points open. The present document discusses various cryptographic techniques of all times such as the three basic algorithms namely private key algorithm, public key algorithm and the hash functions. The need for having three encryption techniques has also been encrypted .A detailed discussion has been done on the classical cryptography and the drawbacks of the classical cryptography to ensure the need for going to new trends in cryptography like quantum cryptography, elliptic curve cryptography. These new techniques that has emerged out of various exploitations in the field of cryptography rises a fair amount of hope that we can over come the problems we are facing in a headhoc way. These proven technologies can meet the needs of the most demanding of environments while their respective focus on manageability has automated many tasks and simplified administrative functions through easy-to-use interfaces developed through years of customer feedback. And at the end of the document we can conclude that soon we can save secrecy involved in message passing from the dangerous clutches of message hackers.
1.INTRODUCTION
The Internet or the global Internet is the internationally connected network of computer networks with addresses that are administrated by IANA (Internet address and Naming Authority). It grew dramatically because anyone can connect to it and any one connected to it can connect others to it as well. Each site that connected to it, can become an Internet Service provider to other sites Does increased security provide comfort to paranoid people? Or does security provide some very basic protections that we are naive to believe that we don't need? During this time when the Internet provides essential communication between tens of millions of people and is being increasingly used as a tool for commerce, security becomes a tremendously important issue to deal with.
There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting passwords. One essential aspect for secure communications is that of cryptography. This paper has two major purposes. The first is to define some of
the terms and concepts behind basic cryptographic methods, and to offer a way to compare the myriad cryptographic schemes in use today. The second is to provide some real examples of cryptography and new trends in use today.
I would like to say at the outset that this paper is very focused on terms, concepts, and schemes in current use and is not a treatise of the whole field.
2.THE PURPOSE OF CRYPTOGRAPHY
Cryptography is the science of writing in secret code and is an ancient art; the first documented use of cryptography is writing dates back to circa 1900 B.C. when an Egyptian scribe used non-standard hieroglyphs in an inscription. Some experts argue that cryptography appeared spontaneously sometime after writing was invented, with applications ranging from diplomatic missives to war-time battle plans. It is no surprise, then, that new forms of cryptography came soon after the widespread development of computer communications. In data and telecommunications, cryptography is necessary when communicating over any untrusted medium, which includes just about any network, particularly the Internet. Within the context of any application-to-application communication, there are some specific security requirements, including:
• Authentication: The process of proving one's identity. (The primary forms of host-to-host authentication on the Internet today are name-based or address-based, both of which are notoriously weak.)
• Privacy/confidentiality: Ensuring that no one can read the message except the intended receiver.
• Integrity: Assuring the receiver that the received message has not been altered in any way from the original.
• Non-repudiation: A mechanism to prove that the sender really sent this message.
Cryptography, then, not only protects data from theft or alteration, but can also be used for user authentication. There are, in general, three types of cryptographic schemes typically used to accomplish these goals: secret key (or symmetric) cryptography, public-key (or asymmetric) cryptography, and hash functions, each of which is described below. In all cases, the initial unencrypted data is referred to as plaintext. It is encrypted into ciphertext, which will in turn (usually) be decrypted into usable plaintext.
In many of the descriptions below, two communicating parties will be referred to as Alice and Bob; this is the common nomenclature in the crypto field and literature to make it easier to identify the communicating parties. If there is a third or fourth party to the communication, they will be referred to as Carol and Dave. Mallory is a malicious party, Eve is an eavesdropper, and Trent is a trusted third party.
3.TYPES OF CRYPTOGRAPHIC ALGORITHMS
There are several ways of classifying cryptographic algorithms. For purposes of this paper, they will be categorized based on the number of keys that are employed for encryption and decryption, and further defined by their application and use. The three types of algorithms that will be discussed are (Figure 1):
• Secret Key Cryptography (SKC): Uses a single key for both encryption and decryption
• Public Key Cryptography (PKC): Uses one key for encryption and another for decryption
• Hash Functions: Uses a mathematical transformation to irreversibly "encrypt" information