WSEAS TRANSACTIONS on ADVANCES in ENGINEERING EDUCATION

Masanori Nakakuni, Eisuke Ito, Yoshiaki
Kasahara, Sozo Inoue, Hiroshi Dozono

Construction and Use Examples of Private Electronic
Notary Service in Educational Institutions
Masanori NAKAKUNI
Research Institute for Information Technology
Kyushu University
6-10-1 Hakozaki, Higashi-ku Fukuoka 812-8581
JAPANnakakuni@cc.kyushu-u.ac.jp http://nlab.tv
Eisuke ITO
Research Institute for Information Technology
Kyushu University
6-10-1 Hakozaki, Higashi-ku Fukuoka 812-8581
JAPAN
itou@cc.kyushu-u.ac.jp
Yoshiaki KASAHARA
Research Institute for Information Technology
Kyushu University
6-10-1 Hakozaki, Higashi-ku Fukuoka 812-8581
JAPANkasahara@nc.kyushu-u.ac.jp
Sozo INOUE
Library
Kyushu University
6-10-1 Hakozaki, Higashi-ku Fukuoka 812-8581
JAPAN
sozo@lib.kyushu-u.ac.jp
Hiroshi DOZONOFaculty of Science and Engineering
Saga University
1-Honjyo Saga 840-8502
JAPAN
hiro@dna.ec.saga-u.ac.jp
Abstract: - People have many documents. For example, a variety of documents are prepared and used in public
institutions. As the internet becomes widely available in recent years, paper documents are being replaced withelectronic data, which are often distributed in the form of electronic data without being printed out. Similarly, in
educational institutions, increasing number of documents are distributed in the form of electronic data. Such data
are distributed through various routes and means, and prone to the risk of alteration in the process. Data may beprotected against alteration, but it is difficult to completely prevent data alteration in the distribution process. Data
can be generated with electronic signature that allows for the identification of data creator and possible alterations
by third parties. This method is, however, not valid if the data becomes separated from the electronic signature,

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Masanori Nakakuni, Eisuke Ito, Yoshiaki
Kasahara, Sozo Inoue, Hiroshi Dozono

making the validation of data creator or data alterations difficult or impossible. In this paper, we describe theinvention of a system that, even in cases where data is separated form the electronic signature, enables easy
identification of possible data alterations by the electronic signature management. And we describe here an
exploratory construction of private electronic notary service in university. We also add a review on the utilization
method of private electronic notary service in universities.
Key-Words: - Notary Service, Electronic Signature, e-Learning, Digital Data Management, PKI

1 Introduction
2 Data management

As the internet becomes widely available in recent
years, academic educational environment has changed
significantly. For example, as e-Learning system
becomes more widely used, lecture materials are being
switched from papers to electronic media. Recently,
some universities are making attempts to distributeeducational video data through their websites. In
addition, changes are also seen in the receiver side ofeducation. In a conventional system, students at
University A were able to take only those lectures
given at University A. In these days, introduction of
credit transfer system has enabled flexible curriculumthat allows students to take lectures of otheruniversities pre-approved in interuniversity exchange
program. University alliance, that is to say that thestudents of University A can take lectures of
University B and vice versa, is becoming morecommon. Moreover, lectures are not limited only to
students at pre-approved universities within theinteruniversity exchange program, but also available
to residents in the neighboring communities.
Lecture materials will be distributed even wider
than ever if the lectures are to be taken not only by
the university constituents but also by people outside
the university. This means that the materials are
more prone to alteration in the distribution process.
Part of lecture materials may get dropped or
miswritten in the process of passing from person toperson. The causes are various including accidents
and intentions, but the alterations of lecturematerials without permission of the creators arelikely to be disadvantageous to the creators and theviewers as well. For example, if a lecture material
gets altered in a way the content is contradictory to
the fact, the creator as an academic staff of theuniversity and the university itself might losecredibility. Therefore, the creator of lecturematerials must take measures against such problems
if he/she is to distribute the materials in a form ofeasily-copiable electronic data.

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2.1 Conventional data management and its
problems
In conventional data management, anti-alteration
protection was the main focus in the preventive
measures against data alteration. However, preventionof data alteration is quite difficult. Even a non-editable
ODF file may be forged into a closely-resembled PDF
file, which is almost as same as alteration. Video data,
created with non-editable setting similar to PDF, mayalso be converted to an editable format by using video
capturing software [1, 2]. That is, even those data withhighly-protective functions can be easily altered bycounterfeiting because the contents are always
displayed to the viewers.

2.2 Data management method in universities
In educational institutions including universities,
strict management is often necessary in order toprevent alteration of data distributed by themselves. It
calls for a system that ensures that the data was createdby faculties or staff of the university, and that the data
has not been altered. One way to do this is to utilize anassurance system similar to notary service [3, 4, 5]. In
this case though, strict assurance by third party is not
required and the university itself will give theassurance. Then the cost can be cut down throughself-management of the notary service by theuniversity, eliminating external commission expense.
Also, all that is required is to provide a method whichallows the viewers to check the possible presence ofdata alteration. A private electronic notary system as
simple as this can be constructed and operated at low
cost. Our proposed system was named PENS from theinitials of “Private Electronic Notary System”.

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formats of data. The PENS database will be managed
by the university. And the message digests and therelated information registered in the database will be
released to the viewers. The viewers will, in
accordance with prescribed procedures, compare andverify the message digest of the obtained data with that
registered in the database, and thereby obtain
information on the data creators and possible
alterations.

3 Data management by electronic
signatures
3.1

Advantages of electronic signatures

The above-described requirements can be satisfied
by the attachment of electronic signature [6] to data.
A brief summary is as follows.
•

Validation of data creator¾ Data creator can be identified.
Verification of data alteration¾ Possible presence of data alteration can bechecked.

•

3.2

3.4 Manipulations
signatures

Common electronic signature methods

PENS Electronic signature method

In the PENS electronic signature method, the data
creator generates a message digest from the data byusing hash function [11, 12, 13], and then register themessage digest and the related information into the
PENS database. PENS is therefore similar to PKI, in
the way that data and the corresponding electronic
signature are separated, giving an advantage that theelectronic signature can be easily applied to any

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of

PENS

electronic

There are three kinds of manipulations for PENS
electronic signatures; “Attachment of electronic
signature”, “Invalidation of electronic signature” and“Verification of electronic signature”.
Procedures for the attachment of electronic
signature is shown in Figure 1. In order to attach an
electronic signature, the data creator will access
PENS through a web browser. The user will beprompted to enter his/her user ID and password for
PENS electronic signature attachment, and the user
must be pre-approved for the signature attachment.
User ID will be provided to faculties, staff, andothers that were approved by the university. First,
the user will enter his/her PENS user ID andpassword to login. Next, the user will upload data towhich an electronic signature is to be attached.
Finally, comments may be added as needed.
Attachment of electronic signature is completed
through the procedures above.
Procedures for the invalidation of electronic
signature is shown in Figure 2. Invalidation ofprevious electronic signature is necessary upon datarevision. In the process of invalidation, the previous
signature attachment history is kept in record while
the signature invalidation history is added.
Procedures are similar to those for electronic
signature attachment. The user will login to PENS,
upload data of which the electronic signature is to beinvalidated, and add comments as needed.
Invalidation of electronic signature is completed
through the procedures above.
Procedures for the verification of electronic
signature is shown in Figure 3. User ID andpassword are not required for the verification of
PENS electronics signature. That is, anyone can use
the verification function. The user is only required to
upload data which is to be verified. If the data has a
PENS electronic signature attached, information of
the creator’s name, etc. will be displayed on the web

One of the common electronic signature methods
is to embed an electronic signature in the data itself.
In this case, the software that handles data must
support electronic signature embedding. Software
may be self-tailored to support the signatureembedding, but it is often difficult in cases where thetechnical specifications for the software are not open.
Even in cases where the technical specifications areopen, the specifications may undergo changes
through version upgrades, which may necessitatechanges of electronic signature method andcomplicate the adjustment process for thecontinuous support of new specifications.
Another method of electronic signature is PKI(Public Key Infrastructure) [7, 8, 9, 10]. PKI uses
secret key for the attachment of electronic signature,and public key for the verification of electronic
signature. In this method, electronic signature is
attached in a separate form without being embeddedin the data, thereby giving an advantage that theelectronic signature can be applied to any formats ofdata. However, if data gets distributed separately,
data verification or assurance is no longer possible.
In order to prevent such events, electronic signature
method has to be evaluated based on the premise of
separate distributions of data and electronic
signature.

3.3

Masanori Nakakuni, Eisuke Ito, Yoshiaki
Kasahara, Sozo Inoue, Hiroshi Dozono

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Masanori Nakakuni, Eisuke Ito, Yoshiaki
Kasahara, Sozo Inoue, Hiroshi Dozono

Figure 2 Procedures for the invalidation of electronic
signaturebrowser, which allows verification of the data
creator and possible alterations.

3.5 Information registered in PENS database

4 Construction of a prototype PENS

The
following
information
concerning
signature-attached data are registered in the PENS
database.
•
•
•
•
•

4.1 System construction
System architecture of the prototype is shown in
Table 1. The system architecture is also shown in
Figure 4.

Message digest
Registered date in PENS
Name of the data creator
Department/division to which the creator belongs
E-mail address of the creator

4.2 PENS operation screens
PENS operation screens are depicted below.
Figure 5 shows the PENS login screen. Figure 6
shows the screen for the attachment of electronic
signature. Figure 7 shows the screen for theinvalidation of electronic signature. Figure 8 shows
the screen for the verification of electronic signature.
Figure 9 shows the screen for the result of
verification.

In addition to the information above, otherinformation may be added as needed. Data itself is
not saved in the PENS database.

Figure 1 Procedures for the attachment of electronic
signature
Figure 3 Procedures for the verification of electronic
signature

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Masanori Nakakuni, Eisuke Ito, Yoshiaki
Kasahara, Sozo Inoue, Hiroshi Dozono

measures have to be taken to distribute load on
PENS server and network. We considered a method
in which message digest is created on each client
terminal and the resulting message digest alone issent to PENS server. This means that a part ofprocessing tasks on PENS server is allocated toterminal computers on the user side. In this method,
PENS server load is distributed and network load isalso reduced by omitting data upload to PENS server.
Hence, the above-mentioned problem can be solved.
We developed PENS client that realizes this method.

4.4 PENS client
Detailed description of PENS client is given below.
As mentioned above, PENS client is a software thatenables a local computer to create message digest
and to send the resulting message digest alone to
PENS server for the attachment of electronic
signature. The development environment andsystem requirements for the PENS client are shownin Table 2.

Figure 4 The system architecture of PENS

Table 1 System architecture of the prototype
Hardware
CPUIntel Xeon
Memory2GByteHDD
250GByte
SoftwareOS
CentOS 5.1
Web Server
Apache 2.2.3
DB
MySQL 5.0
Development Language
Perl 5.8.8
Hash Function
MD5

Table 2 The development environment and system
requirements for the PENS client
Development environment
OS
Microsoft Windows Vista
Programming Language
Hot Soup Processor (HSP)
Version: 3.1
System requirements for PENS clientOS
Microsoft Windows 2000,
2003, XP, Tablet PC Edition,
Vista
CPU
Intel 1.3 GHz processor
RAM
128MB of RAM(256MB recommended)HDD
5MB of available hard disk
space

4.3 Handling of large files in PENS
As mentioned above, in PENS, data is uploaded
onto the server for electronic signature attachment,
and the server performs processing task for creating
message digest according to the uploaded data.
Similarly, invalidation and verification of electronic
signature also requires uploading of relevant data to
PENS server. Data upload to PENS server is time
consuming if the data size is several hundred
megabytes or larger. In addition, network load also
becomes heavy due to the increased datatransmission through the network. Moreover,creation of message digest for larger file causes aheavy load on PENS server. Large-data upload is nota significant problem if it is infrequent, such as a few
times a day. But if large-data uploads count up to
several dozen times a day, or converge in a shortperiod of time, PENS server and the related network
may experience overload and suffer adverse impacts.
And the system will face a greater risk of various
failures. In order to avoid such risk, appropriate

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Host Soup Processor (HSP) [14] is a programming
language that was developed by a Japanese, Onitama,
and are provided free of charge. Currently,
development is underway in the scope of an open
source implementation. HSP supports a variety ofplugins to add extended commands to be used inprograms, and most of these plugins are provided
free of charge. Grammar of the programming
language is similar to that of BASIC. Increasing
number of primary and middle school students inJapan use HSP due to its grammatical simplicity.
One of the notable features of HSP is that highly

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functional software can be developed with short andsimple codes.
Next, start up screen of PENS client is shown in
Figure 10. Basic flow of operation procedures issimilar to those described in 3.4. First, specify a
URL for accessing PENS. ID and password are also
required in case of attachment or invalidation ofelectronic signature. Next, specify the relevant datapass, and select from the pull-down menu an
operation to be performed - electronic signatureattachment, invalidation, or verification. In case ofelectronic signature attachment, enter your name,affiliation, and other information such as data
description at the same time. Lastly, click “Run”
button, and the program will initiate the creation of
message digest, communicate with PENS server,
and perform the specified operation of signature.
Communications between PENS server and clientare secured with SSL data encryption using the https
protocol.

Masanori Nakakuni, Eisuke Ito, Yoshiaki
Kasahara, Sozo Inoue, Hiroshi Dozono

Figure 6 The screen for the attachment

Figure 7 The screen for the invalidation

Figure 5 The PENS login screen

Figure 8 The screen for the verification

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modifications are made. PENS is highly versatile
because its electronic signature attachment is
supported by most file formats including simple text
format. In addition, PENS will play a moresignificant role when the notification has higher
priority.

5.2 Electronic
software

4.5 Technical advantages and disadvantages in
PENS
Advantages and disadvantages in the technicalaspect of PENS are listed below.

•

Advantages¾ Electronic signature can be applied to any
formats of data.
¾ Data can be easily verified and assured evenin cases where data becomes separated fromthe electronic signature.
¾ Simple and compact system enables easy
operation.
¾ Simplearchitecture
enableseasy
manipulation of the system.
¾ Costs of system introduction and operation
are low.
Disadvantage¾ Data alterations cannot be prevented.

5 Example of PENS usage
5.1 Electronic
notifications

signatureattachment

to

Most organizations, including but not limited toeducational institutions such as universities andcolleges, frequently issue various notifications
internally and externally. Such notifications may beposted on website or sent to specified individuals via
e-mail in the form of electronic data. It is difficult toverify the provider of notification in either case. In
other words, those who view a notification cannot
easily confirm the information provider. The issue
may be addressed by PENS. The provider’s identity
can be confirmed by PENS for any notification
issued with PENS electronic signature, regardless of
distribution routes and means, provided no

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attachment

toIn educational institutions including universities,
software programs are developed as part of researchand education activities, and those programs areoften distributed to general public in order to widely
publicize the results. Software may be distributed
through websites that are operated by university, or
personal websites of the developers. Specializedwebsites for software distribution, such as
SOURCEFORGE.NET [15], may be used, and there
are various other ways of distribution. It’s also
possible that software is passed from user to user via
e-mail. In these ways, software may be distributed
through various routes and means, and therefore theprograms and appended documents are prone to therisk of alteration in the process. Even if thedeveloper’s name is clearly stated in a document
contained in the software, users cannot easily
confirm the developer. Therefore, many users areafraid of running software on their computers
without proper identification of the developer. It isout of fear that computer virus infections andspyware activities may cause damages. The issue
may be addressed by PENS. The developer’s
identity can be confirmed by PENS for any software
provided with PENS electronic signature, regardlessof distribution routes and means, provided no
modifications are made. Verification method of
PENS electronic signature can be included in an
appended document, so that users can easily confirm
the developer’s identity by themselves. Distributing
software with electronic signature attachment will
provide a sense of security to users by properly
identifying the developer.

Figure 9 The screen for the result of verification•

signature

5.3 Electronic signature attachment to video
data
Recently, it is becoming common that universities
create video data to put on their websites for publicaccess. In some cases, electronic signature is
attached in order to clarify the creator. An increasing
number of universities and colleges also distributevideo data on YouTube [16]. However, video data

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with electronic signature is not necessarily
compatible with YouTube. The reason is as follows.
Data is automatically and compulsorily converted to
FLV format [17] in the uploading process ofYouTube. At this step, some video data in aparticular format with electronic signatureattachment may not be converted to FLV. Or thevideo data may be converted but the electronic
signature is erased. For example, in case anelectronic watermark is embedded in the video data,
the watermark may become invalid by quality
degradation due to the conversion to FLV format.
Therefore, video data distributed through YouTube
may not contain electronic signature. On the other
hand, PENS can solve the problem. First, video data
will be uploaded to YouTube. Then the video data in
FLV format will be downloaded from YouTube andsaved to a local computer. Electronic signature canthen be attached to the downloaded video data using
PENS.

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Figure 10 PENS client
password also reduces the frequency of ID andpassword data transmission through network,
resulting in lower risk of ID/password
eavesdropping. In this way, single sign-on enhances
the convenience and safety at the same time. We areworking on a method to enhance the convenienceand safety of PENS, in linked operation with a single
sign-on system.
For the purpose of enhancing PENS convenience,
we are also considering the implementation of afunction that enables extensive searching andverification of electronic signatures by linking
multiple PENS constructed at each organization.
The flow is depicted in Figure 11. With this function,
any electronic signature, of which the relevant PENS
organization is unknown, can be verified byaccessing any of the linked PENS. If no informationis retrieved from the accessed PENS, the server willaccess other PENS and send a query to provide theuser with the query result. Implementation of thisfunction will significantly improve the convenienceof PENS.
Our future objective is to further develop PENS byimplementing the function as described above.

6 Conclusions
In this paper, we presented the invention of anelectronic signature system PENS, which was basedon the premise of separate distributions of data andelectronic signatures. Construction of a prototype
system was also described. PENS has features thatenable the data creators to easily attach electronic
signatures to their data and the viewers to easily
verify the data creators and possible alterations,although data alterations themselves cannot be
prevented. When distributing electronic documents
including lecture materials, the university will
provide to the viewers information on the data
creators and alterations, but no other advanced
functions are necessary. In this way, PENS has asimple architecture and simple functions, and still
capable of contributing to the maintenance of theuniversity’s credibility. However, there is one
prerequisite that none of the PENS users operates
with malicious intention. Although it is difficult toeliminate all malicious users, the first measure will
be to prevent unauthorized use by masqueradingusers who stole user IDs and passwords. Current
PENS uses only user IDs and passwords for the user
authentification, which does not provide a robust
security. In order to improve the situation, it isnecessary to incorporate other authentification
methods such as biometric identification [18, 19, 20,
21, 22, 23, 24] and IC card identification [25, 26,27]. From the reason described above, reinforcementof the user authentification function is our main
focus in the future.
We are also conducting a study on single sign-on
system [28, 29, 30, 31, 32], with a view of linked
operation of PENS and single sign-on system. We
are particularly interested in a single sign-on systemcalled Shibboleth [33, 34]. Shibboleth wasdeveloped by the Internet2 [35] Shibboleth
Development Team, and is widely distributed as
open source software. Main feature of single sign-on
and the merit of its introduction are as follows.
When logging in to services that are operated undera single sign-on system, user ID and password will
be prompted once for the first service, and if thelogin state is maintained, logins to other services aresmooth without repeated entering of ID andpassword. This is the main feature of single sign-on.
Repetitive typing of ID and password can be savedby this feature. Reducing the typing tasks for ID and

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Figure 11 Linking multiple PENS constructed at eachorganization
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Kasahara, Sozo Inoue, Hiroshi Dozono

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[33] The Shibboleth Development Team: Shibboleth(A Project of the Internet2 Middleware Initiative),
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[34] Toshihiro Takagi, Takaaki Komura, Shuichi
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[35] Internet2: Internet2, http://www.internet2.edu/.

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Issue 10, Volume 5, October 2008