Application And Research Of Resilient Function In Resilient Fault Tolerance

These years, the researches on dependability of a system have been a hotspot in the field of information. As two properties of dependability, availability and security are always independent because the techniques used to achieve them are usually perceived as mutually uncorrelated. Hence, how to unify these two properties has now become a problem urgently to be solved.In a distributed system, by comparing the techniques used to achieve availability and security we can find: availability is generally accomplished by the fault tolerance technology, which involves space and/or time redundancy, and can easily take advantage of a distributed computing architecture by means of replicated computer with sets of untrusted processors. Here, the fault tolerance denotes that a system can still execute appointed assignment when malfunction takes place on its hardware and/or software. Fault commonly refers to the intrinsic physical fault of a system but not the error. With the development of Internet, malicious faults caused by intruders, such as juggling or eavesdropping information and system failure, become more and more serious. Only by the conventional fault tolerance technologies, a system cannot work continually and properly. In order to defense the faults caused by intrusion, people combining the kernel of fault tolerance put forward a new security measure-intrusion tolerance.By analyzing the application of fault tolerance technologies on the distributed system, this paper expatiates several approaches based on availability and security of the distributed system, and then sets focus on the FRS (Fragmentation-Redundancy-Scattering) fault tolerance technology, which is a resilient fault tolerance technology and has an obvious advantage on improving the system availability and security. The basis of the FRS technique is to cut every sensitive file in such a way that one or more fragments are insufficient to reconstitute the file. These fragments are stored in topologically distributed archive sites. Meanwhile redundancy technology contains the physical faults of the system itself; therefore it can realize the fault tolerance of intrinsic physical fault. However, in the whole process of FRS, how to fragmentize the sensitive file into uncorrelated fragments is yet a very important and painful step.In order to overcome the difficulty mentioned above, this paper proposes a fragmentation algorithm, which is based on resilient function. The algorithm utilizes the physical meaning of resilient function, and combines FRS fault tolerance technology, by adverse transformation of resilient function, then renewably encodes information, finally makes use of the degree of resilience to accomplish information fragmentizing.Numerical examination shows that this algorithm has a good performance both in improving system availability and security. Furthermore, the algorithm is of great theoretical significance as well as application value.