| Client server model provides a convenient way to interconnect distributed applications, more important, it is the basic architecture of the Internet. In the open environment of the Internet, security and reliability are difficult to achieve. Critical personal information stored on computers can be attacked, using techniques such as viruses, phishing and social engineering. Distributed Denial of Service (DDOS) attacks are a significant threat to the reliability of any services provided on the Internet. Anonymous communication systems are vulnerable to many attacks including replay attack, collusion attack and traffic analysis attacks.; To enhance the system security of the client computers, Virtual Machine Monitor (VMM) and the Security Manager (SM) were designed and used to form the trusted platform and check the Operating System's integrity outside the Virtual Machine (VM). Plus, a distinct hardware channel and I/O device, the secure I/O, was used to prevent low level attacks, like keyboard sniffers, screen scrapers, and so on.; To improve the reliability of the critical servers, an infrastructure was designed to dynamically construct and configure server farms using a peer-to-peer architecture. The decentralized, self-organization and scalability characteristics of peer-to-peer architecture ensure that the system will have significantly low management cost, while providing highly reliable services in spite of attacks.; To provide anonymous communications on the Internet, a communication system was built on top of peer-to-peer networks; which is completely distributed, self-organized, and scalable with thousands of active participants communicating simultaneously. |
