Article An approximation algorithm to the file allocation problem in computer networks Share on Authors: Kowtha Murthy Paramus, New Jersey Paramus, New JerseyView Profile , John Kam Wang Research Laboratories, Waltham, Massachusetts Wang Research Laboratories, Waltham, MassachusettsView Profile , M. S. Krishnamoorthy Rensselaer Polytechnic Institute, Troy, New York Rensselaer Polytechnic Institute, Troy, New YorkView Profile Authors Info & Claims PODS '83: Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systemsMarch 1983 Pages 258–266https://doi.org/10.1145/588058.588087Online:21 March 1983Publication History 10citation274DownloadsMetricsTotal Citations10Total Downloads274Last 12 Months1Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

A new cryptosystem that is suitable for database encryption is presented. The system has the important property of having subkeys that allow the encryption and decryption of fields within a record. The system is based on the Chinese Remainder Theorem.

In attempting to solve the problems of data security, researchers, and practititioners are placing increasing emphasis on encryption. An important class of encryption schemes is that of substitution-permutation (SP) encryption networks. A variant of the SP network has been chosen by the National Bureau of Standards as the data encryption standard. In this paper, we introduce the concept of completeness, which captures the intuitive notion of complexity of SP networks. The completeness property is examined and a technique for designigning complete SP networks is demonstrated.

The related fields of privacy and security are examined. Privacy issues are discussed and topics in the security fields of cryptography, database inference and operating systems are re viewed.

Considered here, for a particular model of databases in which only information about relatively large sets of records can be obtained, is the question of whether one can from statistical information obtain information about individuals. Under the assumption that the data in the database is taken from arbitrary integers, it is shown that essentially nothing can be inferred. It is also shown that when the values are known to be imprecise in some fixed range, one can often deduce the values of individual records.

Kildall has developed data propagation algorithms for code optimization in a general lattice theoretic framework. In another direction, Hecht and Ullman gave a strong upper bound on the number of iterations required for propagation algorithms when the data is represented by bit vectors and depth-first ordering of the flow graph is used. The present paper combines the ideas of these two papers by considering conditions under which the bound of Hecht and Ullman applies to the depth-first version of Kildall's general data propagation algorithm. It is shown that the following condition is necessary and sufficient: Let ƒ and g be any two functions which could be associated with blocks of a flow graph, let x be an arbitrary lattice element, and let 0 be the lattice zero. Then (*) (∀ƒ ,g,x ) [ƒ g (0) ≥ g (0) ∧ ƒ( x ) ∧ x ]. Then it is shown that several of the particular instances of the techniques Kildall found useful do not meet condition (*).

Article Free Access Share on Application of lattice algebra to loop optimization Authors: Amelia Fong Princeton University, Princeton N. J. Princeton University, Princeton N. J.View Profile , John Kam Princeton University, Princeton N. J. Princeton University, Princeton N. J.View Profile , Jeffrey Ullman Princeton University, Princeton N. J. Princeton University, Princeton N. J.View Profile Authors Info & Claims POPL '75: Proceedings of the 2nd ACM SIGACT-SIGPLAN symposium on Principles of programming languagesJanuary 1975 Pages 1–9https://doi.org/10.1145/512976.512977Online:01 January 1975Publication History 13citation241DownloadsMetricsTotal Citations13Total Downloads241Last 12 Months8Last 6 weeks4 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF