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Introduction to
Computer Security
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Introduction to
Computer Security
Matt Bishop
Boston • San Francisco • New York • Toronto • Montreal
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Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trade-
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Library of Congress Cataloging-in-Publication Data
Bishop, Matt (Matthew A.)
Introduction to computer security / Matt Bishop.
p. cm.
Includes bibliographical references and index.
ISBN 0-321-24744-2 (hardcover : alk. paper)
1. Computer security. I. Title.
QA76.9.A25B563 2004
005.8—dc22
2004019195
Copyright © 2005 by Pearson Education, Inc.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted,
in any form, or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the
prior consent of the publisher. Printed in the United States of America. Published simultaneously in Canada.
Chapters 17 and 18 Copyright 2005 by Elisabeth C. Sullivan. Published by Pearson Education, Inc. with
permission.
For information on obtaining permission for use of material from this work, please submit a written request to:
Pearson Education, Inc.
Rights and Contracts Department
75 Arlington Street, Suite 300
Boston, MA 02116
Fax: (617) 848-7047
ISBN: 0-321-24744-2
Text printed on recycled paper
1 2 3 4 5 6 7 8 9 10—CRS—0807060504
First printing, October 2004
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To my dear Holly; our children Heidi, Steven, David, and Caroline; our
grandson Skyler; our son-in-law Mike; and our friends Seaview, Tinker Belle,
Stripe, Baby Windsor, Fuzzy, Scout, Fur, Puff, and the rest of the menagerie.
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Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxv
Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvi
Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxvii
Organization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxix
Differences Between this Book and
Computer Security:
Art and Science
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxx
Special Acknowledgment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxi
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxi
Chapter 1 An Overview of Computer Security. . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.1 The Basic Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.1.1 Confidentiality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
1.1.2 Integrity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.1.3 Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.2 Threats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.3 Policy and Mechanism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
1.3.1 Goals of Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.4 Assumptions and Trust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.5 Assurance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
1.5.1 Specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1.5.2 Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1.5.3 Implementation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1.6 Operational Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
1.6.1 Cost-Benefit Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
1.6.2 Risk Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
1.6.3 Laws and Customs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
1.7 Human Issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
1.7.1 Organizational Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
1.7.2 People Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
1.8 Tying It All Together. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
1.9 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
1.10 Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
1.11 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
vii