Table Of ContentLecture Notes in Computer Science 1528
Editedby G.Goos,J. Hartmanisand J.van Leeuwen
3
Berlin
Heidelberg
NewYork
Barcelona
HongKong
London
Milan
Paris
Singapore
Tokyo
Bart Preneel Vincent Rijmen (Eds.)
State of the Art in
Applied Cryptography
Course on Computer Security
and Industrial Cryptography
Leuven, Belgium, June 3-6, 1997
Revised Lectures
1 3
SeriesEditors
GerhardGoos,KarlsruheUniversity,Germany
JurisHartmanis,CornellUniversity,NY,USA
JanvanLeeuwen,UtrechtUniversity,TheNetherlands
VolumeEditors
BartPreneel
VincentRijmen
KatholiekeUniversiteitLeuven
Dept.ofElektrotechniek/ESAT
K.Mercierlaan94,B-3001Heverlee,Belgium
E-mail:[email protected]
[email protected]
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Stateoftheartinappliedcryptography:revisedlectures/Course
onComputerSecurityandIndustrialCryptography,Leuven,Belgium,
June3-6,1997.BartPreneel(ed.).-Berlin;Heidelberg;NewYork
;Barcelona;HongKong;London;Milan;Paris;Singapore;
Tokyo:Springer,1998
(Lecturenotesincomputerscience;Vol.1528)
ISBN3-540-65474-7
CRSubjectClassification(1998):E.3,D.4.6,K.6.5,F.2.1-2,C.2,J.1
ISSN0302-9743
ISBN3-540-65474-7Springer-VerlagBerlinHeidelbergNewYork
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Preface
The Department of Electrical Engineering-ESAT at the Katholieke Universiteit
Leuvenregularlyrunsacourseonthestateoftheartandevolutionofcomputer
security and industrial cryptography. The (cid:12)rst course took place in 1983, the
second in 1989, and since then the course has been a biennial event.
The course is intended for both researchers and practitioners from industry
and government. It covers the basic principles as well as the most recent de-
velopments. Our own interests mean that the course emphasizes cryptography,
but we also ensure that the most important topics in computer security are
covered. We try to strike a good balance between basic theory and real-life ap-
plications,betweenmathematicalbackgroundandjudicialaspects,andbetween
recent technical developments and standardization issues. Perhaps the greatest
strength of the course is the creation of an environment that enables dialogue
between people from diverse professions and backgrounds.
In 1993, we published the formal proceedings of the course in the Lecture
Notes in Computer Science series (Volume 741). Since the (cid:12)eld of cryptography
has advanced considerably during the interim period, there is a clear need to
publish a new edition. Since 1993, several excellent textbooks and handbooks
on cryptology have been published and the need for introductory-level papers
has decreased. The growth of the main conferences in cryptology (Eurocrypt,
Crypto,andAsiacrypt)showsthatinterestinthe(cid:12)eldisincreasing.Inaddition,
new conferences have emerged (such as Fast Software Encryption and Informa-
tion Hiding) which illustrate the expansion of the research. These conferences
o(cid:11)er ample opportunity to present new research results. However, there is still
a need for papers presenting an overview of the state of the art in areas that
areparticularlyimportantfor applications,or papersintroducing novelareasor
applications. We believe that the authors of this volume have done an excellent
jobinexplainingrecentdevelopmentsinawiderangeoftopicswithinthisexcit-
ing area.We thank them for their considerablee(cid:11)orts.We alsoacknowledgethe
assistanceofallmembers ofourresearchgroupCOSIC(Computer Securityand
Industrial Cryptography) in the preparation and running of another successful
course.
Finally, we would like to dedicate this book to the memory of Rita De Wolf,
whodidanoutstandingjobinorganizingourcourses,butwhowasalsoavaluable
friend and colleague.
Leuven, Belgium B. Preneel and V. Rijmen
1998
Table of Contents
Trends in the Fight Against Computer-Related Delinquency............. 1
Bart De Schutter
Block Ciphers — A Survey.......................................... 18
Lars R. Knudsen
Cryptographic Primitives for Information Authentication — State of the
Art .............................................................. 49
Bart Preneel
Recent Developments in the Design of Conventional Cryptographic
Algorithms........................................................ 105
Bart Preneel, Vincent Rijmen, Antoon Bosselaers
Elliptic Curve Public-Key Cryptosystems — An Introduction............ 131
Erik De Win, Bart Preneel
Key Management Techniques........................................ 142
Walter Fumy
Security of Computer Networks...................................... 163
Jan Verschuren
Internet Security Protocols.......................................... 186
Walter Fumy
Securing Internet Electronic Mail .................................... 209
Mark Vandenwauver, Frank Jorissen
GSM: Security, Services and the SIM ................................. 224
Klaus Vedder
TTPs Overview — Concepts and Review of the State of the Art from a
Technical Point of View............................................. 241
Peter Landrock
Management of Secret Keys: Dynamic Key Handling ................... 264
Joan Daemen
On Solutions to the Key Escrow Problem ............................. 277
Mark P Hoyle, Chris J. Mitchell
Smart Cards — Requirements, Properties and Applications ............. 307
Klaus Vedder, Franz Weikmann
VIII Table of Contents
Smart Card Security ............................................... 332
Ernst Bovenlander
Security Aspects of the EcashTM Payment System ..................... 338
Berry Schoenmakers
International Standardisation of IT Security........................... 353
Klaus Vedder
Security Management — The Process ................................ 366
David W. Roberts
Introduction to Computer Security................................... 377
Bart De Decker
Author Index ................................................. 395
Trends in the Fight Against Computer-Related
Delinquency
Bart De Schutter
Center for the interaction between law and technology
Vrije Universiteit Brussel
1 The Phenomenon
The grasp of information technology upon almost all societal activities is an
indisputable and irreversible fact. Transfer of data, information, knowledge or know-
how has undergone with the technological wave a profound change in its form, speed
and distance coverage. This mutative effect can certainly be beneficial to society in all
its components (economic, strategic, intellectual, cultural).
It seems, however, that the margin between use and abuse is rather narrow. Even if
criminality related to information has always existed, the intervention of the computer
with its above-mentioned characteristics of time, volume and place, leads to the risk
of a criminal activity, the nature of which might be different from the more classical
information crimes. To look into the phenomenon, its size frequency and profile, will
lead to the necessary conclusion for the need of policies, which may be necessary to
effectively combat this anti-social behaviour.
In that exercise one encounters a number of difficulties. A first one concerns
already the definition of computer delinquency. According to the purpose for which it
is needed, one can work with a more criminology-oriented definition, describing the
deviant pattern from the sociological angle, or could need a more precise terminology
when introducing the illegal act as crime in the penal arena, then requiring precise
material and moral elements in the definition. Avoiding the multitude - and the
nuances - of definitions of the expert writers [1], there is much merit in the OECD
working definition, referring to "any illegal, unethical or unauthorised behaviour
relating to the automatic processing and/or the transmission of data" [2], since the
answer to computer criminality is likely not to be limited to an exercise of criminal
law drafting alone.
However, the danger of such an extensive "opening definition" is that it allows a
somewhat overqualification of incidents, in which the computer does not play any
instrumental role at all. Some demystifying and relativation has to be done to bring
the phenomenon back into real proportions, avoiding the sensationalism of its media
coverage.
Scarcely a day passes without any newspaper-clip on computer-crime or fraud.
Television picks up the item and visualizes the "hacking" techniques. The difficulty,
however, is to bring those individual findings into some global figures and clear
indicators. This seems, often, to be too delicate, if not impossible.
There is clear reluctance and unwillingness in communication of incidents. Banks,
insurance companies or any other potential victim are not easily communicative on
B. Preneel, V. Rijmen (Eds.): COSIC'97 Course, LNCS 1528, pp. 1-17, 1998.
ª Springer-Verlag Berlin Heidelberg 1998
2 Bart De Schutter
losses occurred through incidents related to their information system. Image-loss,
indirect consequences such as the thrust of the customers or the competitive position,
all push towards secrecy and discretion. The simple anonymous transfer of
information for statistical purpose to official instances, even international ones, is
objected to. The interference of judicial authorities is considered as being "counter-
productive".
Many of the incidents come in the daylight through indiscretion, erroneous
behaviour of the criminal himself or when insurance companies oblige the client to do
so before refunding any loss. Besides, some countries are more communicative than
others [3]. For sure one can state that figures are incomplete, that guesses should be
considered with care and that we only know the top of the ice-berg.
Since several years a considerable number of official bodies or professional circles
are showing interest in gathering valuable information. All of it should be read with a
critical eye, since under- or overscoring is likely. Nevertheless, figures are impressive
and worthwhile to be recalled : SRI mentions 100 million $/year in the U.S., the FBI
makes two billion dollars out of it [4]. For Europe, an interesting estimate is the one
of the Association Internationale pour l'Etude de l'Assurance, which comes up with
six billion dollars loss for Europe already in 1988. A U.K. survey by the Local
Government Audit Inspectorate led to 80 % of 320 interviewed firms having been
victim of a computer fraud [5], while in 1985 four major British banks budgeted £ 85
million against computer frauds. The French CLUSIF reports a yearly amount of
nearly 11 billion FF of voluntary or accidental damaging of information systems.[6]
It is not the purpose of this paper to recall the spectacular and classical examples
such as the Equity-funding [7] or Security Pacific Bank [8], or Memorial Sloan
Kettering Cancer Institute [9], the French ISOVER Case [10] or the CLODO
activities [11], or many other [12] not to forget the Internet misbehaviours or
"cybercrimes" such as pornography, libel or racism [13] but it may be important to
recall that not all incidents are linked to economic interests as such, but may equally
concern health, privacy, morality or state strategic survival.
If the overall size of computer abuses is substantially high, though not full-proof, it
has also been shown that these totals concern a limited number of victims.
Concentrating the losses upon few leads to the conclusion that the average gain of
such crime is a hundred times that of the average classical hold-up, while the average
time for the discovery of the misbehaviour seems to be counted in years, not in
months [14].
To be added to this picture is the great potential of the transborder dimension of
information technology, whereby the physical presence of the actors across the border
is no longer necessary. The internationalization of this criminality adds a new
dimension to the task of society in reacting against this phenomenon.
As to the actors themselves, they seem roughly to fall into two major groups: on
one hand the computer-freaks, the youngsters trying to hack systems for fun,
competition, challenge; whizkids or wargamers, i.e. "short-pants criminality", not
necessarily with a clear criminal intent; on the other hand, willful criminality by
hackers or employees within the system, often highly qualified and technically
skilled, often acting from within, abusing the hi-tech and jargon oriented "state in the
state" position of the EDP-sector.
In conclusion on the characteristics of the phenomenon one can say that
information systems, whether used for simple data storage or retrieval, word
processing, business activities, banking, electronic fund transfer, electronic mail,
