DESIGN AND IMPLEMENTATION OF AN INTRUSION TOLERANT SYSTEM. A RESEARCH PROJECT MATERIAL ON COMPUTER SCIENCE EDUCATION
Most current information systems are connected to the Internet for efficiency and convenience. However, the growth of accessibility makes the systems vulnerable to attackers. A web server is a program that runs over the Hyper Text Transfer Protocol which has client-server mode to serve clients with files and other details which are stored on the server. The web server is currently the most widely deployed type of distributed data server. Every computer on the internet that contains a website must have a web server program. Web servers are providing dynamic contents rather than static ones which have opened up many security flaws.With the development and scope of cloud computing, there is a tremendous shift in the web hosting industries. Most users prefer a server in the cloud due to ease of maintenance and low cost of infrastructure thus there is a great need to ensure the integrity and confidentiality of the systems we use. For this reason, many studies have been conducted in order to improve security of information systems. To protect the private keys of web servers and certificate authority, (Boneh et al, 1999) shared the keys among a number of share servers.
1.2 BACKGROUND OF THE STUDY
A dependable system is defined as one that is able to deliver a service that can justifiably be trusted; attributes of dependability include avaliablity ( readiness for correct service), reliablility (continuity of correct service), confidentiality (prevention of unauthorised disclosure of information), and integrity (absence of improper system state alterations)(Avizenis et al, 2001).
Large network infrastructures, such as the Internet, are vital for citizens to benefit from the services provided by theZ Information Society. However, users must be able to trust the services offered to them. MAFTIA (Randell et al, 2003), an European Union funded project investigated a comprehensive approach for tolerating both accidental faults and malicious attacks in large-scale distributed systems, thereby enabling them to remain operational during attack, without requiring time-consuming and potentially error-prone human intervention. SITAR (Sargor et al, 2001) uses commercial-off-the-shell servers to provide intrusion tolerance to distributed systems.
Emerging applications like electronic commerce and secure communications over open networks have made clear the fundamental role of public key cryptography as unique security solutions. On the other hand, these solutions clearly expose the fact that the protection of private keys is a security bottleneck in these sensitive applications. This problem is further worsened in the cases where a single and unchanged private key must be kept secret for very long time (such is the case of certification authority keys, and e-cash keys).
When classified information is sent electronically from one individual to another, some form of encryption must be used to protect the information from prying eyes. Because internet technology relies on the transmission of data through the public domain, this encryption is absolutely essential to preserving the security of electronically-transmitted information. Public key encryption, which was first developed in the 1970s, has gradually come to dominate the “cryptology market” because of its innate advantages over private-key methods of encrypting data; unlike its counterpart, public key encryption does not require that individuals share a secret key.