Cryptographic Solution to a Problem of Access Control in ... - CiteSeerX

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in the design of computer operating systems to control information flow from one program to another [1, 3]. This paper presents a solution based on cryptography ...
Cryptographic Solution to a Problem of Access Control in a Hierarchy SELIM G. AKL and PETER D. TAYLOR Queen's University, Canada

A scheme based on cryptography is proposed for access control in a system where hierarchy is represented by a partially ordered set (or poset). Straightforward implementation of the scheme requires users highly placed in the hierarchy to store a large number of cryptographic keys. A timeversus-storage trade-off is then described for addressing this key management problem. Categories and Subject DescriPtors: D.4.6 [Operating Systems]: Security and Protection--access controls; authentication; cryptographic controls; information flow controls; E.3 [Data]: Data Encryption--Data Encryption Standard (DES); public-key cryptosystems. General Terms: Security Additional Key Words and Phrases: Multilevel security, cryptography, key, symmetric and asymmetric cryptosystems

1. INTRODUCTION A s s u m e t h a t t h e u s e r s of a c o m p u t e r (or c o m m u n i c a t i o n ) s y s t e m are d i v i d e d i n t o a n u m b e r of d i s j o i n t sets, /_}1, U2 . . . . . Un. T h e t e r m security class (or class, for short) is u s e d to d e s i g n a t e e a c h of t h e Ui. A s s u m e f u r t h e r t h a t a b i n a r y r e l a t i o n _< p a r t i a l l y o r d e r s t h e set S = ( U1, U 2 , . . . , /_7,} of classes. T h e m e a n i n g of Ui