The History Of The Wireless Setup

Published Date: 02 Nov 2017

Cryptography broadly consists of three aspects –encryption, decryption and key management. Encryption is a process to transform the data into some unreadable form. Its objective is to ensure confidentiality from anyone for whom it is not intended. Decryption is the reverse of encryption. The process of decryption makes the encrypted data into intelligible form. Key management is the most important cryptographic activity for achieving security in transmission of information. Most of the research on key management has concentrated on designing efficient and secure two-party key distribution systems. All key distribution schemes are fundamentally based on mathematical problems that are difficult to solve. Number theoretic concepts like integer factorization, prime number generation, random Number generation, Chinese remainder theorem, discrete logarithmic problem are important issues related to public key and symmetric key distributions.

Public key distribution is ideal to provide authentication services in wired networks. However, the main problem of public key based security system is to make each user’s public key available to others in such a way that its authenticity is verifiable. Symmetric key based mechanisms are attractive for bootstrapping secure communication between communicating parties because of energy efficiency and low computational complexity. However, there are few limitations of these schemes. Firstly the communicating parties must meet each other before they communicate with each other.

Whitefield-Diffie and Martin-Hellmann introduced a key distribution scheme known as Diffie-Hellmann key exchange scheme. The security of Diffie-Hellman Scheme is based on the trap-door one way function (Discrete Logarithm Problem). The disadvantage of Diffie- Hellmann (D-H) key exchange scheme is that it is susceptible to an attack known as man-in-the-middle attack. Lack of authentication in the D-H scheme makes the system vulnerable to this attack. However, Ronald L. Rivest, Adi Shamir and Leonard Adleman proposed a public key distribution scheme known as RSA key distribution. The basic idea behind RSA is that different keys are used for encryption and decryption. The security of RSA is based on the difficulty of finding the factorization of a large composite positive integer that is the product of two large primes. Because of long keys, RSA scheme takes a large computation time for encryption and decryption. Hence, RSA based schemes are not suitable for encrypting large amounts of traffic. Therefore, efficient scheme for key generation and distribution has been proposed in this thesis. In this research work, a key management technique based on Pythagorean triple has been proposed. A novel mechanism for determining all Pythagorean triplets has been formulated. The proposed key distribution system has been proposed that not only generates a secure key but also incorporates user authentication .

Literature Survey

According to Kerckhoff, the security of any cryptosystem lies in the key. If a cryptosystem uses a weak key generation process, then the entire system becomes vulnerable to security attacks. Once a key is randomly generated, it must remain secret to avoid security attacks. Designing secure cryptographic algorithms and protocols is difficult, but proper management of cryptographic key is much more difficult[1]. Apart from key generation and its distribution, authentication of the legitimate users is equally important. Reliable user authentication also allows authenticated users specific rights and privileges. It forms an integral part of secure key distribution.

In this research work, most of the key distribution protocol used in wired and wireless setup has been surveyed.

Whitefield-Diffie and Martin-Hellmann[2] in 1976 devised a solution to the problem of key known as Diffie-Hellmann key exchange scheme. The security of Diffie-Hellman Scheme is based on the trap-door one way function (Discrete Logarithm Problem). However, the D-H scheme was not designed with any authentication. G.J.Popek et al.[3] have provided a key exchange scheme with symmetric cryptography. This scheme uses a trusted key distribution centre. The disadvantage of this scheme is the keys must be distributed before the start of the protocol. The interlock protocol [4], invented by Adi Shamir and R. Rivest, overcomes the problem of man-in-middle attack. Bellovin et al.[5] have presented an attack on the Rivest and Shamir’s interlock protocol which permits access to one side of the conversation and, if shared secrets are re-used, eventually to both sides. Wide-Mouth Frog protocol and Yahalom protocol[6][7] provide a scheme for authentication and key exchange. These protocols use a trusted server. Both the source and destination share a secret key with the trusted server. The biggest drawback of these protocols is that the source is competent enough to generate good session keys. However, random numbers are not so easy to create. Needham and Michael Schroeder[8] have developed a protocol which uses symmetric key cryptography and a trusted server. The advantage of the protocol is that it prevents replay attacks. The prevention of replay attack is done by the use of random numbers. However, Denning et al.[9], have presented an attack by exploiting the reuse of old session keys. Again in 1987, Needham and Michael Schroeder[10] have corrected their problem in a modified version of their protocol. In Kerberos[11], which is a variant of Needham- Schroeder protocol, two entities authenticate each other via a globally trusted certifying authority (CA). This scheme is ideal for wired networks of manageable scale. However, it does not work well in wireless networks.

A large number of private and public key user authentication and key exchange mechanism exist in the literature[12][13][14][15][16][17][18]. Al-Riyami et al.[19][20] have introduced the concept of public key certificate less cryptography. In this thesis, an attempt has been made to generate and distribute cryptographic keys in certificate-less settings.

Motivation

These days’ people need to access the Internet in offices, homes and hotels. Due to rapid advancements in information and communication technologies and growth of mobile market, the Mobile Internet has also arrived. It has started revolutionizing the Internet into a pervasive technology. It is now becoming increasingly common to keep the office work going while on the move. Internet access is no more limited to closed and controlled environment of offices, homes and hotel rooms. It has come out in open and often alien surroundings of cafes, conference rooms, lobbies and even moving vehicles. Today there are an increasing number of places where users can power up their laptop fitted with a Wi-Fi wireless LAN adapter and connect to the internet. Locations such as airports, hotels, coffee shops, and even private homes are becoming hosts for providing Internet Services. Such locations have some backbone infrastructure to provide the Internet services to the visitors. To access the services, the users get themselves connected to the backbone using Wi-Fi enabled devices such as laptops, palmtops etc. through wifi access points and routers.

Providing proper security services to support for authentication, confidentiality, integrity, non-repudiation, access control and availability is critical for deployment of wireless technology in commercial applications. To provide all these services, a secure key distribution mechanism is required. An improper key distribution compromises the authentication and confidentiality issues in information security. A scheme for providing a secure key distribution has been presented in the thesis. Through this research work an attempt has been made to undertake a comprehensive study on security problems of wireless technology and provide possible solutions to alleviate the security related issues.