Browsing by Author "HWANG, MS"

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A 2-KEY-LOCK-PAIR ACCESS-CONTROL METHOD USING PRIME FACTORIZATION AND TIME STAMP
(1994-09-01)
HWANG, MS
;
TZENG, WG
;
YANG, WP
;
交大名義發表
;
資訊工程學系
Many methods, based on the concept of key-lock-pair have been proposed for access control in computer protection systems. However, the proposed methods still either lack of dynamic ability or need quite a lot of computation in performing requests of deleting users/files, inserting users/files, or updating access rights of users to files. In this paper we propose a two-key-lock-pair access control method that is based on the unique factorization theorem and a time stamp mechanism. Our method is dynamic and needs a minimum amount of computation in the sense that it only updates at most one key/lock for each access request, which has not been achieved before.
A 2-PHASE ENCRYPTION SCHEME FOR ENHANCING DATABASE-SECURITY
(1995-12-01)
HWANG, MS
;
YANG, WP
;
資訊工程學系
;
Department of Computer Science
In this article, we propose a two-phase encryption algorithm for data base systems. The system, a record-oriented cryptosystem, allows the encryption and decryption of fields within a record by means of writing and reading subkeys of fields. In addition, we develop two algorithms for cryptographic relational algebra in data base systems. Two simple methods of solving the key management problem in the subkey scheme are presented.
A MODIFIED CRITERION FOR OPTIMAL LINEAR TIME-INVARIANT OBSERVER PROBLEMS
(1994-06-01)
HWANG, MS
;
LEE, FC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A modified criterion for designing a linear time-invariant observer is studied. This criterion is a compromise between errors due to stochastic and modal-type deterministic signals. The advantage of this criterion is in its design potentiality to take care of both transient and steady-state behavior. Theoretical properties such as existence, uniqueness, and stability of the optimal solution can be guaranteed for detectable systems under a weak stabilizability condition, which is satisfied by any reasonably defined problem. Moreover, under the criterion, relationships with other existing methods are also discussed.
A MODIFIED CRITERION FOR OUTPUT-FEEDBACK TRACKING PROBLEMS WITH DETERMINISTIC AND STOCHASTIC SIGNALS
(1995-09-01)
HWANG, MS
;
LEE, FC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A modified criterion for designing a linear time-invariant controller for an output feedback tracking problem is studied. This criterion takes the responses due to stochastic and deterministic signals into account. The advantage of this criterion is in its design potentiality to take care of both performances due to stochastic and deterministic signals in a time-invariant controller. Theoretical properties of this criterion include existence, uniqueness and closed-loop stability of the optimal solution. Moreover, this solution satisfies a separation property and incorporates a required internal model for the tracking requirement.
A NEW DYNAMIC ACCESS-CONTROL SCHEME BASED ON SUBJECT-OBJECT LIST
(1994-11-01)
HWANG, MS
;
YANG, WP
;
資訊工程學系
;
Department of Computer Science
The topic of access control modes is a very important subject in the field of information protection systems. In this paper, we shall propose a new access control mode, the subject-object-list (SO-list), for a system which adds, removes, and updates subjects and objects frequently. The main advantage of the SO-list is that the number of lists remains constant despite the changes in the number of subjects/objects. Furthermore, by applying the key-lock-pair mechanism to the list, we allow a new subject/object to be added to or an existing subject/object to be removed from the system without recomputing a large number of key/lock values. Thus, our method achieves real dynamicism.
A NEW DYNAMIC CRYPTOGRAPHIC KEY GENERATION SCHEME FOR A HIERARCHY
(1994)
HWANG, MS
;
YANG, WP
;
資訊工程學系
;
Department of Computer Science
A NEW SERVICE FOR DIGITAL MOBILE COMMUNICATIONS
(1994)
HWANG, MS
;
WEY, JK
;
YANG, WP
;
資訊工程學系
;
Department of Computer Science
CONFERENCE KEY DISTRIBUTION SCHEMES FOR SECURE DIGITAL MOBILE COMMUNICATIONS
(1995-02-01)
HWANG, MS
;
YANG, WP
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a new service for digital mobile communication systems, The service enables two or more users to hold a secure conference, Two requirements must be considered: privacy and authentication. Privacy involves ensuring that an eavesdropper cannot intercept the conversations of the parties holding the conference. Authentication involves ensuring that service is not obtained fraudulently in order to avoid usage charges. We present two new conference key distribution schemes for digital mobile communication systems. In these schemes, a group of users can generate a common secret key over a public channel so that they may hold a secure conference.
MODIFIED CHANG-HWANG-WU ACCESS-CONTROL SCHEME
(1993-11-25)
HWANG, MS
;
YANG, WP
;
CHANG, CC
;
資訊工程學系
;
Department of Computer Science
It is found that some security classes in the Chang-Hwang-Wu access control scheme can be combined to derive the secret key of their immediate ancestor in some cases. Some slight modifications to the proposed scheme to enhance the security levels are also given.
PERFORMANCE RECOVERY VIA A CONTROLLERS INITIAL-STATE ASSIGNMENT FOR AN OUTPUT TRACKING PROBLEM
(1994-12-01)
HWANG, MS
;
LEE, FC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper deals with the optimal output feedback problem of how to initialize a controller's state when the initial value of the system is known. Special attention is paid to a tracking problem. Owing to the design freedom of the controller's initial state, there exist optimal controllers to recover the optimal performance that a state feedback law can attain. Other advantages with our optimal controllers are the requisite internal model and an invariance property, which shows that the assignment of a controller's dynamic parameters is independent of the-system's initial state.