助成

Institute forInternational Policy Studies
・Tokyo・

IIPS International Conference“The IT Revolution and Security Challenges”
Tokyo
December 10-11, 2002

“Information Security–Driving Force behind the IT Revolution”
byShigeo Tsujii
Professor
Faculty of Science and Engineering
Chuo UniversityJapan‑ The IT Revolution and Security Challenges ‑Information Security–Driving Force behind the IT
Revolution
ユビキタス社会における自由と安全-情報セキュリティ環の構築に向けて【IIPS 10 December 2002】

10 December 2002

Chuo University Faculty of Science andEngineering
Information and Systems Engineering
Department
Shigeo Tsujii

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【IIPS 10 December 2002】

1. Preface – A Change of Perspective
Hegel (1770–1831)“History… is none other than the progress of the consciousness of
freedom, and we must recognize its inevitability.”
Contemporary researcher in cryptography (1933-?)“What a genius Dr Hegel was! His admirable vision transcended
the time and place in which he lived. At the dawn of the 21st century
it seems as if the computer, like God, is omnipresent, and that its
continuing ubiquity will bring marked increases in our freedom.
However, hand-in-hand with the growth of freedom, various inherent
anxieties and insecurities are manifesting themselves. As acontemporary cryptography researcher, I think about ways to use
encryption technology to enhance freedom, while reducing to aminimum any issues of security, or concerns relating to the possible
creation of a surveillance society. Today I would like to address thesematters, with reference to various examples such as electronic voting
systems.”
It could be thought that Hegel’s principle, that history is the process of thedevelopment of freedom, which was framed in reference to the real world, is even more
applicable to the real world when it is combined with the added dimension of thecyber-world.
For example, encryption technology—a core technology in the field of information
security—is thought of solely as a technology for protecting the cyber-world, whereas inreality it is expanding the cyber-world and bringing people greater levels of freedom.
Let us consider these matters in relation to electronic voting and electronic surveys.
At present, Japanese local governments are attempting to introduce voting systems
for voters at polling stations. In a genuine electronic voting system, the voter can votefrom any terminal and from anywhere via the Internet or a similar medium.
If this type of genuine electronic voting (henceforth referred to simply as “electronic
voting”) becomes possible, it is predicted that the percentage of people voting will rise,bringing significant change to the current political landscape, in which voting rates
have been declining.

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【IIPS 10 December 2002】

Electronic voting need not be confined to elections only; it will also become easy toissue questionnaires and conduct surveys on individual political issues, thereby
significantly increasing freedom of political involvement citizens. With electronic voting,anonymity must be guaranteed; in e-business and related fields too, many people
would be willing to reply to questionnaires, provided that they could do so anonymously.
The construction of such a system would enable businesses to operate successfullyusing the “information pull” model.
In addition to the necessity for preserving voter anonymity and protecting against
voting irregularities (such as the casting of multiple ballots), electronic voting (or any
comparable activity) imposes the following strict requirements which must be satisfied
in a verifiable manner: that the vote-tallying center must calculate the vote totals
properly, that the ballot-counting stations must count the votes properly, and that thepreferences of individual voters must remain absolutely secret.
For the first time, solutions to this kind of major challenge are now generally being
implemented using current encryption technology, such as public-key encryption andzero-knowledge interactive proofs.
For this reason, information security technology—including encryption—is not
merely a technology for the purposes of protection, but a technology which alsoenhances the growth of individual freedom and forms a solid foundation for the new
cyber-world.
However, the growth of the cyber-world is also bringing out people’s anxieties about
safety and their fear of an omnipotent society.
In an article entitled “A Discussion of the Freedom of Information—the Power of Dataand the Ethics of Encryption,” serialized in the October 2002 issue (No. 172) of the“Central Review,” the philosopher Hiroki Azuma writes the following:
The Two Strata of Post-Modernism
Diversity of requests and thoroughness of information control—readers may wellfeel that these two coexisting tendencies are mutually contradictory. However,there is no contradiction here. This is because this new control which is being
demonised in this case is different from that of Big Brother, as depicted byOrwell. It is not related to ideology – in short, it is not related to any sense ofvalues or norms.
Although it is good that diverse values exist, and with maximum possible
recognition for civil and economic liberty notwithstanding, if information solely
on who did what, when, and where, is always collected, this could if necessary

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【IIPS 10 December 2002】

have a profound effect on the lives of certain individuals. Moreover, thisinformation is collected without the individual’s knowledge, as in the example of
the automatic ticket machine cited at the end of the previous installment. This isa characteristic of the power to control the environment, which underpins
post-modern society.
The stratum of diversity and the stratum of information control, the ideology
stratum and the security stratum, in other words the stratum ruled by theprinciple of tolerance and the stratum ruled by the principle of exclusion. It is acharacteristic of our society that these two strata remain separate.
We specialists in encryption and information security assume an obligation to eradicate
fears of this kind of omnipotent society. At the same time, while preserving safety andreliability for individuals, companies, and vital infrastructure at every level of stateand society, we assume an obligation to construct an environment in which the privacyof individuals is protected and freedom can be enjoyed. To achieve all of the above
requires a finely detailed scheme to increase freedom, improve safety, and quell fears ofan omnipotent society; this scheme must meet the challenge of balancing mutuallycontradictory requirements, introduce methods such as decentralized authority andmanagement, and achieve compatibility between its three goals. Cooperation in every
aspect—technology, management and administration, the legal system and ethics—isindispensable.
Moreover, it is desirable that all citizens of the cyber-world—not just the specialists
in the fields mentioned above—should be more conscious of the need for information
security.
A full 10 years after first establishing information security guidelines in 1992, theOrganization for Economic Cooperation and Development (OECD) released revised
guidelines in August 2002. Whereas the old edition set out ideas for measures toprotect the safety of computer systems, the new edition, entitled OECD Guidelines for

the Security of Information Systems and Networks, propounds the necessity for strong
safety measures in response to the diverse threats currently posed in the global
network environment with its open information systems. These ideas are expressed innine principles. Within these principles, the two expressions “culture of security” and“participant” stand out. There are as many definitions of “culture” as there are cultural
anthropologists; however, the author of this paper would define culture as the sum
total of a given group’s inherent values, ethics, behavior patterns, and lifestyles. If
culture is interpreted in this way, then the participants on the network comprise a3

【IIPS 10 December 2002】

group (that is, the entire population of the cyber-world, not just the information
security specialists), and it can be said that the new guidelines make an appeal to all
the people of the advanced IT nations to share in an awareness of information security.
In our capacity as specialists we must design systems that meet with society’s
approval and also accept the responsibility for explaining matters to society at large.

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【IIPS 10 December 2002】

2. The Ubiquitous Society and Increases in Freedom
Computerization is progressing in different spheres of society. Not a day goes by
without a flood of newsprint devoted to e-money, computerized medical records,
electronic voting, computerized tax filing, e-government (both national and local) or
some other computerized activity.
Let us call this society, in which computerization is advancing on many fronts, the“ubiquitous society.” The ubiquitous society may be regarded as a society based on afoundation of computer and information network technology. Within that complex
multi-dimensional space, one can make use of various coordinate axes. However, to theauthor of this paper, there are many social issues to consider relative to the coordinate
axes of freedom and safety.
The question “What is freedom?” is a difficult one to answer. However, with theadvent of networking founded on digital technology, various barriers between
organizations have been lowered and society has assumed a contiguous structure. If
one looks at the effect of this on freedom of behavior, it cannot be denied that thevarious practical benefits brought about by computerization have also resulted inincreased personal freedom. Let us explain this in slightly more detail.
The digital technology underlying the spread of ubiquitous computing is creating aborderless world through the power of distributed computing. More fundamentally, it isconnecting all corners of society. Looking at the larger picture, as this technology
brings about a continuous structure in society, it is also giving rise to a paradoxical
phenomenon, which can only be described as a “digital analog” identity crisis.
In the same way that all matter is formed of atoms and molecules, all forms of
information, such as sounds and images, can be digitised into signals representing 0 or
1. As the ubiquitous computer, linked by network to its peers, has become a staple ofsociety, it is now easy to process, edit, generate, transmit, search, and share thisinformation.
This has become a major factor increasing the interconnectedness of manufacturer
and consumer, author and reader, broadcasting and communications, government andpeople, public and private, the internal and external workings of a company,
businessman and individual, workplace and home, work and leisure, politician andcitizen, nation and nation, scientific and cultural pursuits, and so on and so forth,removing the time and space barriers between industries, organizations, and regionswith a momentum that gives rise to a principle called the interconnectivity of society.
For example, in the realm of copyright too—the key to the increased popularity of4

【IIPS 10 December 2002】

digital broadcasting and the like—the phenomenon of continuity between creator andconsumer is progressing. For many consumers it is now easy to edit original
information and add one’s own ideas to it. There are many such cases in which theprinciple of “fair use” is substantially violated.
Thus, while the barriers between different systems and groups are being lowered andfreedom is spreading, it is also true that causes of anxiety and elements of danger
continue to increase in number.
In the realm of computer and network crime, a criminal act committed in cyberspace
may have an immediate effect in a location on the opposite side of the world, or may
even leave no trace at all, if the location in which it was committed cannot be
determined.
In addition, threats to e-society are posed not only by people acting in bad faith orwith malicious intent, but also by human error and breakdowns or other calamities
occurring on computers and other information devices.
Given this situation, the greatest challenge of the ubiquitous society is to enhancesafety so that people can enjoy freedom to the greatest extent possible. Freedom musthave a safe and solid platform on which to stand. In the following section, we willconsider the framework of information security.

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【IIPS 10 December 2002】

3. Constructing the Ring of Information Security
Information security is usually defined as follows:
Information security is the protection of information assets, in terms of confidentiality,
integrity, and availability, against various threats and attacks on their security, so that
normal functions and conditions are preserved, information systems and the reliabilityof information is enhanced, and users can use information systems in peace of mind.
Hence, since the 1970s “confidentiality,” “integrity,” and “availability,” the initials of
which spell “CIA,” have been regarded as the three components of information security.
These concepts are formally defined in Table 1
Table 1. Confidentiality, Integrity, and Availability
Confidentiality
Only a person who has permission to access particular information canaccess it.
Integrity
Information and its associated processing methods are authentic andcomplete.
Availability
The ability of authorized users to access information and related assets
reliably whenever necessary is preserved

To put it simply, “confidentiality” is the protection of privacy and industrial secrets. Fora long time encryption has figured prominently as a means of achieving confidentiality.
“Integrity” means that information cannot be falsified. If a website has been altered bysomeone who is not authorized to do so, its integrity has been compromised.
“Availability” signifies that a person can use a resource such as a computer whenever
he wishes to. If a DoS (denial of service) attack, for example a spam attack, renders amail system unusable, then its availability has been compromised.
Do these three elements together constitute a complete definition of information
security? Although explanations like the one above appear in recent literature on thesubject, if one considers the importance of electronic certification, one has to say that
this is an inadequate definition.
When electronic business transactions, e-government business and the like arecarried out, it is essential that it be possible to verify the identities of both the parties
involved. If it proves impossible to confirm a person’s identity with absolutecertainty—whether due to intentional deception or accidental error—e-society will
collapse completely. The invisibility inherent in the cyber-world makes it a fertile
environment, both for malicious deception and accidental error. To protect against thiskind of occurrence, it must be possible to carry out electronic certification reliably using

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【IIPS 10 December 2002】

identification of individuals and digital signatures.
In accordance with this line of thought, some recent commentators have added afourthinformation

securityelement—certification—to

theexisting

trio

of

confidentiality, integrity, and availability. The concept of provability includes the notionthat a transaction will leave behind a record of the time at which it took place, as proof
that it took place. Some may think that the notion of certifiability is easier tounderstand than provability; however, the prevailing view seems to be that it is easierfor people to comprehend and remember three elements than four. The author too is
undecided, but my current thinking is as follows.
The definition of integrity given in Table 1 is somewhat abstract. It is also possible toframe a definition of integrity that also includes reliable certification and proof.
In short, 20 years ago integrity was understood to mean “error-free data.” However,for practical purposes it would seem preferable to expand the definition to encompass
the concepts of certification and proof.
This kind of information security, then, is not something that can be protected using
technology alone. Management and administration within organizations must be
carried out reliably. People working in organizations must apply high ethical standards.
Information ethics are important. However, since it cannot be assumed that all people
are virtuous in nature, a system of laws to deal with information crime must be put inplace.
Ultimately,toachieveinformation

security

these

four

items—technology,

management and administration, the legal system, and ethics—must be interlockedwith one another to construct a ring of strength, as shown in fig. 2.
Let us consider the car, which is a metaphor that is easy to understand. To enable
trouble-free driving, the following are required:(1) Technology: both the car’s components, such as the engine, and the car itself (thefinished product comprised by the components) must be well designed.
(2) Management and administration: even if one has purchased a car of high quality, it
is important to keep it in good condition by carrying out maintenance checks
diligently and sending it for periodic inspections, to improve one’s driving technique,and to always drive safely.
(3) Legal system: traffic laws and a legal system to deal with violations of these laws
must be properly established in advance.
(4) Ethics: it is important that everyone adheres to good driving etiquette.
This analogy makes it easier to explain how technology, management andadministration, the legal system, and ethics apply to information security.

7

【IIPS 10 December 2002】(1) Technology
In addition to encryption technology—the main theme of this paper—the list oftechnologies also includes technology for identification of an individual using
bio-information, technology for the protection of copyright using electronic watermarks
and the like, counter-measures to combat viruses, firewall technology, and network
security technologies such as intrusion detection systems (IDSs). For example, it ispresumed that encryption is used to conduct narcotics dealing in secret. In order tofully utilize technology for the safety of individuals and society, it is necessary toconstruct a watertight wheel of security that fully encompasses management andadministration, the legal system, and ethics.
The phrase “information security” contains strong overtones of protection.
Encryption is the core technology in information security. But is encryption only atechnology for protection? In fact, encryption is a driving force behind computerization
and an engine of revolutionary change in society. Let us consider e-money as an
example.
e-money is a currency in which technology such as digital signature technology(based on public-key encryption) is used to attach value to information to represent anamount of money. The banknotes in use today derive their monetary value from the useof advanced printing technology and paper quality. However, in the cyber-world, which
is built out of computers and networks, it is not possible to produce a currency where
value is accorded based on material attributes. This currency will come into being asfollows: using public-key encryption, only currency issuers, such as the Bank of Japan,
will be able to use their secret private keys (which are kept secret) to perform amathematical operation to attach a digital signature to information representing anamount of money.
e-money is in the vanguard of e-society and it is said that in the future it will bringabout a seismic shift in the international economy. It is only with the advent ofencryption that it has become possible to implement the e-economy system (of whiche-money forms a part). This is also true of a great majority of the systems introduced aspart of the computerization of society, such as e-government systems (both at thenational and local levels) and computerized medical record systems. In light of this, it
might be argued that to regard encryption as simply a technology of protection is toseriously belittle it.
This type of information security, which incorporates encryption technology, is much
more than a framework for “protection” and can be seen as a firm foundation on whichto construct society.

8

【IIPS 10 December 2002】(2) Management and administration
How can information security be preserved in organizations such as companies andlocal governments?
Firstly, it is essential to clarify which of the organization’s information assets need
protecting, carry out analysis to determine the potential threats to these assets, andformulate a security policy. This policy will be a set of rules (like a constitution)
determined at senior management level, and based on the organization’s management
principles. Secondly, it is necessary to adapt the international standards laid down by
bodies such as the ISO (the International Organization for Standardization), or theestablished domestic standards based on these standards, to the business ororganization, and determine practical criteria and guidelines.
In the field of information security the following international standards are
well-known:
ISO/IEC 15408
ISO/IEC 17799
The IEC is the organization known as the International Electrotechnical Commission.
Standards determined jointly by the ISO and IEC are written “ISO/ICE;” however,these two standards are abbreviated below as ISO 15408 and ISO 17799. A brief
explanation of these two standards is in order. ISO 15408 is laid down as a provision
standard for when organizations purchase so-called IT (information technology)
products, such as computers or IC cards. This standard effectively started life in the
mid-1980s as a computer procurement standard established by the US Department of
Defense. Subsequently, starting in around 1990, extended standards were determinedfor general government and civilian use. This also took place in various European
countries, such as Germany and the UK. These standards were combined into what is
now ISO 15408. ISO 15408 consists of functional requirements and warranty
requirements. Functional requirements define the required functions of an IT product.
Warranty requirements define the degree of reliability to which the product’s purported
functions are guaranteed when the product is implemented.
Functions are divided into 11 categories as shown in Table 2. These categories arethen further subdivided. There are two categories which relate to the use of encryption:
encryption key management functions and administration functions required for use of
encryption. In general, if advanced features are requested in IT products, it is assumed
that these features will also be designed to function reliably. Hence, the US
Department of Defense standard of the 1980s did not distinguish between functional9

【IIPS 10 December 2002】

requirements and warranty requirements, but regulated the two together in terms of
IT product safety levels. In about 1990 Germany developed the idea of regulating these
two sets of requirements separately, and the present-day ISO 15408 standard is now
structured accordingly.
In Japan it can be said that the history of ISO15408 began in 1997. This is anabsolutely shocking fact. In fact, in the early stages of the 1990s, the author served as
chief investigator on the Security Subcommittee to the Open Environment
Consolidation Committee established by the Ministry of International Trade andIndustry (as it was then known), and carried out a detailed investigation of computer
security evaluation standards in the US and Europe. In Japan, however, awareness of
information security was low (users particularly were indifferent to it). In addition,
there exists an unspoken perception that, since the manufacture of advanced products
is Japan’s forte, and since manufacturers’ after-sales service is also of high quality,
these types of standard are unnecessary. There was also strong sentiment that thehigher product costs and increases in time-to-market resulting from compliance withthese standards would be serious drawbacks. In addition, the prospect ofinternationally recognised or global standards did not carry sufficient weight. For
reasons such as these, there was little stimulus in Japan for debate regarding
computer security evaluation standards, and discussion stagnated.For these reasons,Japan lags approximately 10 years behind Europe and the US in terms of humanresources training in this field. This is becoming a serious problem.
ISO 15408, which was explained above, is a procurement standard for organizations
buying IT products. The standard that defines management measures for the use of IT
products, information systems and the like which have already been purchased, isknown as ISO 17799.

This ISO standard has been adapted from Part 1 of the UK

standard BS 7799 (which consists of a Part 1 and a Part 2). As shown in Table 3, it isdivided into 10 different management fields. In Japan the ISMS (Information Security
Management System) has been established in conformity with these standards.

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【IIPS 10 December 2002】

Table 2
ISO 15408 Security Function
Categories
Security auditing
2. Communications/denial
prevention

Table 3
ISO 17799 Information
Security Management Fields
1. Security policy
2. Security organization

3. Use of encryption

3. Asset classification and control

4. Protection of user data

4. Personnel security

5. Identification and verification
6. Security management
7. Privacy
Security function protection
8. Availability and resource
management
9. Access control
10. High levels of authenticity
and reliability

5. Physical and environmental
security
6. Communications andapplication management
7. System development andmaintenance
8. Access control
9. Business continuity planning
10. Compliance11

【IIPS 10 December 2002】(3) Legal system
In order to get society to make use of technology, it is necessary to make adjustments tothe legal system. For example, the electronic signature law—or “Law Concerning
Electronic Signatures and Certification Services” to give it its exact name—came into
effect in April 2001. With this law, a legal foundation was established enabling people
to use digital signatures that use public-key encryption to conduct e-business
transactions and e-government activities (both national and local) in peace of mind.
A discussion of the legal system is beyond the scope of this document. However,
several laws relating to information security which are being deliberated at the time ofwriting (July 2002) are shown in Table 4.
Table 4. Examples of Laws Relating to Information Security

Law for the Protection of Computer Processed Data Heldby Administrative Organs

Date ofEnactment/
Effective Date
Under
deliberation
Under
deliberation

Law to Amend Sections of the Criminal Law

2001/7/4

Draft Law on Amending Sections of Commercial Law

2001/11/28
2002/4/1

Name of Law
Draft Law on Protection of Information on Individuals

Electronic Consumer Contract and Electronic Consent
Notification Law
Law Concerning Electronic Signatures and Certification
Services

2001/6/29
2000/5/31
2001/4/1

Copyright Law (revised in 2000)

2000/5/8

Commercial Registration Law (revised)2000/4/19

Notary Public Law (revised)2000/4/19

Law on Enforcement of the Civil Code (revised)2000/4/19

Law on Monitoring of Communications for Investigationof Crime

1999/8/18
2000/8/15

Law on Citizens Register (revised)

1999/8/18

Law Prohibiting Unauthorized Access

1999/8/13
2000/2/13

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【IIPS 10 December 2002】(4) Ethics
Although we speak constantly of ethics, there is an element of doubt about whether
ethics can exert any influence in advancing information security. However, this ismankind’s first attempt at constructing the cyber-world; and in the course of thisprocess, the rapid rise of values and morals relating to information will, in the opinionof the author, become a great unseen force in advancing information security. I will say
no more on this subject.
In conclusion, although I have discussed how it is only with strong cooperation
between technology, management and administration, the legal system, and ethics that
information security can advance, in this lecture I would particularly like to highlightthe example of electronic voting systems. Using encryption technology to protect
against dishonest activity, electronic voting systems are overcoming the major
challenge of privacy protection and paving the way to e-democracy. As such, they
constitute an excellent example of the points discussed above.

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【IIPS 10 December 2002】

4. The Development of Modern Cryptography
The preceding sections have sketched out an overview of information security. Here let
us summarize a topic frequently referred to already—recent trends in modern
cryptography (the main subject of this document).
Although the history of cryptography goes back several thousand years, cryptography
as we understand it today began no more than about four and a half centuries ago.
“Modern cryptography” refers to the cryptography which performs an essential role ine-society, which is based on the technological foundation of computers and networks,
and also in the ubiquitous society.
Less than 30 years after its birth, modern cryptography has now matured intechnological terms, and, in a profound sense, has spread its roots widely to become afoundation of society. Even though it may be premature to try and chart thedevelopment of modern cryptography, due to various 1990s phenomena such as thesystematisation of research into safety theory, the dramatic rise to prominence of thecomputer, and the resultant rapid growth of the Internet, one might think that, at theend of the twentieth century, the world of cryptography is also beginning anew.
Accordingly, although it is somewhat crude, let us think of the final period of thetwentieth century as the first era of modern cryptography, and the dawn of thetwenty-first century as the second. (See fig. 7.)
In the first era shared-key encryption is represented by DES (Data Encryption
Standard) and public-key encryption is represented by ordinary (or primitive) RSA.
Twenty-odd years ago DES was established in 1977 as the standard encryption
method for use by the United States’ government. Now, despite its historic role, its
mission is about to end, due to factors such as the limitations of the 56-bit key lengthand Matsui’s linear cryptanalysis proposition. In the United States AES (Advanced
Encryption Standard) has been established in place of DES. In general, a key length of
128 bits is used. With regard to safety, safety certification (expressing safety
certifiability) must be attached, indicating the ability to withstand well-known attack
methods, such as the diff decryption method and the linear decryption method.
On the other hand, although RSA encryption has for a long time reigned supreme in
the field of public-key encryption, here too significant change can be seen on two fronts.
Firstly, based on both empirical and theoretical evidence, it appears possible that thebasic (primitive) RSA method may not be capable of withstanding an active andadaptable decryption attack. Accordingly, around the year 2000, it was recommended
that the RSA-OAEP method, which carries out pre-processing, be used as the primitive

14

【IIPS 10 December 2002】

RSA method. When exposed to any kind of powerful attack, even plain-text 1-bit
information cannot be decrypted (provided that the primitive RSA method is one-way).
This kind of processing is required for all public-key encryption, not just for RSA
encryption.
In the field of safety theory, recently a more advanced and refined paradigm, KEM(Key Encapsulation Mechanism) has emerged. Together with El Gamal public-key
encryption, which relies on the difficulty of the discrete logarithm problem, this allows
a more unified and generalized description.
Another development in public-key encryption is the implementation of elliptic
encryption. RSA encryption relies on the difficulty of prime factor decomposition.
However, since calculation for decryption requires standard exponential time, in order
to combat computer ubiquity and the exponential increase in computer processing
power over the years, the number of digits in the factors used must be continually
increased. At present, the key length is 1024 bits; however, within 10 years it willprobably be necessary to increase the key length to 2048 bits. By way of comparison,
elliptic encryption and fast elliptic encryption rely on the difficulty of the elliptic curve
discrete logarithm problem. Calculation for decryption requires exponential time. The
same level of safety achieved using the RSA method and a key length of 1024 bits canbe guaranteed by elliptic encryption with a key length of approximately 160 bits.
In addition, compared to RSA encryption, these types of encryption require relatively
small increases in key length to cope with the threats posed by increased computer
processing power and computer ubiquity. For example, whereas the key length for RSA
encryption will have to be increased from 1024 bits to 2048 bits, it is estimated that
elliptic and fast elliptic encryption will only require an increase from 160 bits to 210
bits.
In practice, elliptic encryption, which was invented in the mid-1980s, is attracting
great attention. This is due to the merits of applications such as the use of public-key
encryption to verify identity by embedding the private key on an IC card—the potential
passport to the cyber-world.
In addition to the various technological changes which have taken place, there havealso been other advances. As mentioned previously, on the legal front the “Law
Concerning Electronic Signatures and Certification Services” came into effect in April
2001. In regard to standardization, a committee (known as CRYPTREC) with members
drawn from the Ministry of Public Management, Home Affairs, Posts andTelecommunications, the Ministry of Economy, Trade, and Industry, communications
and broadcasting organizations, information-processing promotion associations, the15

【IIPS 10 December 2002】

bureaucracy, universities, NTT, the world of industry and various other fields, wasformed in the fiscal year 2000 to identify encryption technology which could be used in
e-government. This committee continues to carry out its activities with great vigor.

16

【IIPS 10 December 2002】

Error/
malicious intent

Disaster/failure

e-business/e-life

The developmentof the network

e-government (both national andlocal)The developmentof the computer

Verification of identity andguarantee of authenticity of
documents(Integrity)
Privacy ― protection ofindustrial secrets(Confidentiality)
Preserving the efficiency of
information systems(Availability)

Globalisation

Increased Popularity
of Broadband

Increased Openness

Fig. 1 Information security and the development of an IT society

Technology

Legal System

Increases in Freedom
Information security
Safety of Society
and the Nation
Management
and administration

Information
ethicsFig. 2 Constructing the wheel of information security

17

【IIPS 10 December 2002】

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human resources

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T

information communications network structure

Driving research and development

Bridging the digital divide

Dealing with problems suchas employment problems

Driving force behind international
cooperation and services

Fig. 3 IT Strategy Headquarters’ e-Japan Strategy

e-government

e-business

Advanced information networks
Foundation of information security

Fig. 4 e-Japan

18

Reform of attitudes(both national and local)

Computerized medical
and welfare records

Training of human resources

e-Life【IIPS 10 December 2002】
Increases in freedom
Reshaping of society
through information security
e-government (bothnational and local)
e-economy
Encryption
technology
Protection of
information security

Fig. 5 Encryption and information security—driving forces behind the e-society
Secrecy

Verification

Shared key◎○

Public key○◎

Methods
Type(secrecy of communications messages)
Functions ofencryption technology

Protection/
Secrecy

Verification of identity ofother party in communications

Verification

Certification of integrity ofcommunications messages

Improper denial(Preventing denial that a sender using
a digital signature transmitted data)

Fig. 6 Methods and functions of encryption

Education
Assurance
Risk analysis
Operation and management
Cryptographic protocol
Physical protection
Cryptographic algorithm
Tamper-resistant IC cards' tamper-resistance characteristics

Key management
Security policy
Legal system
Information communications ethics

Fig. 7 Information security from the viewpoint of cryptography

19

【IIPS 10 December 2002】

undBackgroundkeyon
Shared-key encryption

Exponential increase in calculator power

Quantum computer
Spread of the Internet, development of next-generation Internet

Algorithms Public
Establishment of DES

Domestic
Establishment of AES (US government standard)
Rijndaeldevelopmentof
encryption
US government standard
FEAL, MULTI, MISTY, CIPHERUNICORN, E2
Kasumi, Camelia
Stream encryption theory research(1977)Development of decryption algorithms
diff decryption method (1990), algebraic decryption
linear decryption method (1993) (1995-)
128-bit key-length era (128-256 bits)

64-bit key-length era (56-64 bits)eyon

Public-key encryption

Developmentof
public-key
encryption
British defence facility?
USA RSA (1977)
Shared DH key method(1976)

Invention of the zero-knowledge proof protocol (1985)

Synthesis of
Inventionofelliptic Fault-tolerant quantum computer algorithm study (subject) substantive
encryption (1986)
calculation
RSA change to OAEP (1995) KEM (2001)
safetyEPOC (1998) Kurosawa (1999)
Substantive information safety study
Cramer-Shoup (1998)

encryption

1970

Physical safety investigation
Change to OAEP / KEM / elliptic

RSA encryption

1980

1990

2000

2010

Fig. 8 Development of shared-key and public-key encryption

20