Efficient dispersal of information for security, load balancing, and fault tolerance-英文文献.pdfVIP

Efficient Dispersal of Information for Security, Load Balancing, and Fault Tolerance MICHAEL 0. RABIN Harvard University, Cambridge, Massachusetts Abstract. An Information Dispersal Algorithm (IDA) is developed that breaks a file F of length L = ( F( into n pieces F,, 1 5 i 5 n, each of length ( F, 1 = L/m, so that every m pieces suffice for reconstructing F. Dispersal and reconstruction are computationally efficient. The sum of the lengths ( F, 1 is (n/m) . L. Since n/m can be chosen to be close to I, the IDA is space eflicient. IDA has numerous applications to secure and reliable storage of information in computer networks and even on single disks, to fault-tolerant and efficient transmission of information in networks, and to communi- cations between processors in parallel computers. For the latter problem provably time-efftcient and highly fault-tolerant routing on the n-cube is achieved, usingjust constant size buffers. Categories and Subject Descriptors: E.4 [Coding and Information Theory]: nonsecret encoding schemes General Terms: Algorithms, Verification Additional Key Words and Phrases:Fault tolerance, parallel computers, routing of data, storage of data 1. Introduction The storage and transmission of data tiles in distributed systems gives rise to significant security and reliability problems. We may assume the availability of a dependable encryption system, but even then various dangers remain. Consider a user who keeps tiles at a certain workstation. By encrypting the files and taking appropriate care of the encryption/decryption keys, the user ensures the confiden- tialily of the information when other peop