THE

EXISTENCE PROOF SERVICE OF THE WEB PAGES

New Web Service to Get Grounds of the Existence of the Web Pages

Yuka Obu

, Masahiro Miyata

, Juyeon Choe

, Katsumi Terakado

and Tatsuhiro Yonekura

Graduate School of Science and Engineering, Ibaraki University, Hitachi, Ibaraki, Japan

KCS Corporation, Mito, Ibaraki, Japan

Department of Computer and Information Sciences, Faculty of Engineering, Ibaraki University, Hitachi, Ibaraki, Japan

Keywords:

Existence proof service, Time stamp, Electronic ofﬁcial document.

Abstract:

Recently, more people exchange the information via the Web. However, because the information on the Web

is electronic-base data, the information can be deleted or changed frequently. Therefore, it is difﬁcult to prove

to the third party that the content existed or it has not been changed. Hence, we developed the Web service

called “The existence proof service of the Web pages” that creates the Web cache and adds the time stamp

as the grounds that the cache has not been changed. With this service, the Web page can be proved to have

existed in a certain URL at certain time. This can be used for veriﬁcation of the alteration of the Web page.

1 INTRODUCTION

Recently, because of the wide u se of the Internet,

more people exchange the information via the Web

and they can see a lot of scenes that the Web tech-

nology is used to get information. However, because

the information on the Web is electronic-base data,

the information can be deleted or changed frequently.

There are some cases that we can not ﬁnd the same

information on the same URL afterward. Therefore,

it is difﬁcult to prove to the third party that the content

existed or it has not been changed. This is one of fac-

tors to lower the reliability of the Web information. It

is necessary to preserve Web information beforehand

to prove the existence of information.

We can ﬁnd some Web services that can be used

for this purpose. However, these Web services only

make the Web caches. There are no grounds which

prove that the cache has not been changed. Although

some Web services create a PDF ﬁle from the Web

page with the time stamp, peculiar information of the

Web, like meta-tag or link, can not be preserved in

this kind of cache.

Hence, we released the Web service called “The

existence proof service of the Web pages” that cre-

ates the Web cache and adds the time stamp as the

grounds that the cache has not been changed. It can

be proven that the Web page existed on an URL at the

certain time and that the content of cache has not been

changed. Moreover, in this paper, the purpose of use

of the Web service, user’s attribute, and the degree of

the interest had been analyzed.

2 RELATED WORKS

It is necessary to preserve information on the Web be-

forehand in order to prove the existence of the content

at a certain time. There are some Web services that

can be used for this purpose.

“toread” (sidefeed, Inc., 2008) makes the cache of

the requested Web page, and sends it to registered e-

mail address. The user can conﬁrm the content of the

Web page later. “Web Gyotaku” (Afﬁlity. Co.,Ltd.,

2006) records the cache of the requested Web page on

the server. Users can refer the cache on this service in-

stead of the original Web page. “kwout” (HeartRails

Inc., 2007) enables the user to clip a part of the Web

page as an image and quote it. The clipped data is able

to be contributed to “Flickr” (Yahoo! Inc., 2004) or

“Tumblr” (Tumblr Inc., 2007). “Wayback Machine”

(Internet Archive, 1996) enables user to retrieve and

inspect the cache acquired automatically. The re-

quested URL is retrieved and archived contents of the

572

Obu Y., Miyata M., Choe J., Terakado K. and Yonekura T.

THE EXISTENCE PROOF SERVICE OF THEWEB PAGES - New Web Service to Get Grounds of the Existence of the Web Pages.

DOI: 10.5220/0001838805720576

In Proceedings of the Fifth International Conference on Web Information Systems and Technologies (WEBIST 2009), page

ISBN: 978-989-8111-81-4

Web page are displayed in the time series. These ser-

vices only make the cache of the Web page simply,

therefore they can not prove that the cache has not

been changed after the creation, by using some ev-

idences. Consequently, even if the deletion and the

change of the Web page can be recognized, trust from

the third party cannot be obtained.

“HTML2PDF.BIZ” (Asial Corporation, 2007)

preserves the Web page as PDF ﬁle with the time

stamp. When the URL is input, the appearance of

the Web page is converted to a PDF ﬁle. The PDF

ﬁle with the time stamp can be veriﬁed that it has

not been falsiﬁed. However, because this service uses

PDF ﬁle, the preserved information is limited only for

the screen shot. Thus, the particular information in

the Web page maintained in the HTML though not

displayed when referring by the browser, e.g. meta

data, link URL, and so on, can not be preserved.

To deal with issues mentioned above, the new ser-

vice that can prove the existence of the Web page,

namely, “The existence proof service of the Web

page”, has been developed and released.

3 THE EXISTENCE PROOF

SERVICE OF THE WEB PAGES

3.1 The Time Stamp

These days, enormous quantity of data came to be ex-

changed on the Web, even if it is very important. Be-

cause the electronic document do not keep the signs

of correction, and so on, and they do not deteriorate,

it is difﬁcult to trace the history. Hence, the mecha-

nism that proves “When”, “Who”, and “What data” is

important for the evidence of data securing.

In electronic data such as ﬁles, the time stamp can

be the evidence that ensures the following two effects.

The Proof of the Existence. It can be proven that

data existed certainly at the date when the time stamp

was given.

The Proof of Completeness. It can be proven that

the data has not been falsiﬁed since the data when the

time stamp was given.

The electronic data with the time stamp is made at

the time stamp authority, by uniting time information

with the hash value of the data (Adams et al., 2001).

In the veriﬁcation of the data falsiﬁcation, by compar-

ing former data with the hash value of data with the

time stamp, it can be conﬁrmed that the data existed

at the time indicated with the time stamp and is not

falsiﬁed after that.

In Japan, Ministry of Internal Affairs and Commu-

nications (MIC) issued the guideline of time business

(MIC, 2004a), (MIC, 2004b). And based on th guide-

line, the accreditation program established to approve

if the services of a TA (Time Authority) and a TSA

(Time Stamping Authority) meet the required criteri-

ons (JADAC, 2005).

3.2 Genaration of the Web Cache with

the Time Stamp

The existence proof service of the Web pages (the ex-

istence proof service hereafter) had been developed

and released (KCS Corp. and Yonekura lab. at Ibaraki

University, 2008). This service proves the Web page

existed in a certain URL at a certain time and the

cache of the Web page has not been falsiﬁed after it

was generated. The service makes the cache of the

Figure 1 is a screenshot of using this service.

Figure 1: Screenshot of getting the cache from the existence

proof service of the Web page.

Figure 2: Overview of the existence proof service of the

Web pages.

Figure 2 shows the outline of the existence proof

service. The steps to use this service are as follow; (1)

The user sends the URL of the Web page, which he or

she wants to get the evidence of the existence, to this

service. (2) Service acquires information on the Web

page from received URL and makes cache. (3) The

THE EXISTENCE PROOF SERVICE OF THEWEB PAGES - New Web Service to Get Grounds of the Existence of the

Web Pages

573

service requests the time stamp server to add the time

stamp to the created cache. (4) The service replies to

the user cache with the time stamp.

The ways to use this service are (1) user accesses

to the Web site of the existence proof service and in-

puts the URL of the Web page, (2) user uses the tool-

bar for a Web browser that the existence proof service

offers. The toolbars are for Internet Explorer shown

in ﬁgure 3 and for Firefox.

Figure 3: Screenshot of the the IE toolbar for the existence

proof service.

Cache and the time stamp on the Web page are

downloaded to the user with the ZIP ﬁle by using

this service. Figure 4 shows the composition of the

downloaded ZIP ﬁle. The downloaded ZIP ﬁle is de-

compressed, two ﬁles, cahes.zip and caches.zip.tst.

HTML, CSS, and Image ﬁles are compressed into

the caches.zip. Caches.zip.tst is the time stamp ﬁle

for caches.zip. The HTML ﬁle decompressed from

caches.zip is permitted to be conﬁrmed. However,

when new caches.zip is created again from the de-

compressed HTML ﬁles, it is considered that the ﬁles

has been falsiﬁed by veriﬁcation process described in

3.3. Therefore, it is necessary to preserve caches.zip

with caches.zip.tst.

Figure 4: The contents of the downloaded ZIP ﬁle.

3.3 Veriﬁcation

It is veriﬁed that the cache ﬁle downloaded from the

existence proof is not falsiﬁed with a time stamp and a

free veriﬁcation tool that PFU Ltd. offers (PFU Lim-

ited, 2004). Figure 5 is a screenshot of the veriﬁcation

tool. First of all, the ﬁle paths of the time stamp and

the cache are registered (Figure 5

°). Next, the veriﬁ-

cation button is pushed for the veriﬁcation execution

(Figure 5

°). Then the result of the veriﬁcation is

displayed (Figure 5

°).

In the veriﬁcation tool, the veriﬁcation is achieved

using the hash value contained in the cache and the

time stamp. The hash value is calculated using the

same function used when the time stamp was gener-

ated. If the hash values are the same, it is conﬁrmed

that the cache has not been falsiﬁed.

Figure 5: Screenshot of the veriﬁcation execution.

4 THE ANALYSIS OF THE USERS

4.1 Users of the Existence Proof Service

The existence proof service was released to the public

on January 21, 2008, in Japan (Nikkei Inc., 2008),

(CyberAgent, Inc., 2008), (ITmedia Inc., 2008),

(Rakuten, Inc., 2008). Page of the service till Octo-

ber 8, 2008 is 21895.

When the existence proof service toolbar is down-

loaded, the user answers the questionnaire. The num-

ber of valid response is 162 people, and the results are

shown in Table 1, Table 2, and Table 3.

Table 1: Result of the questionnaire about age group.

Age Number Percentage (%)

10 - 19 28 17.3

20 - 29 60 37.0

30 - 39 39 24.1

40 - 49 25 15.4

50 - 59 9 5.6

60 - 69 0 0

70 - 1 0.6

Table 2: Result of the questionnaire about occupation.

Ocupation Number Percentage(%)

Employee 73 45.1

Manager 3 1.9

Part-timer 6 3.7

Self-emplyed 7 4.3

Public service 7 4.3

Student 44 27.2

Without occupation 6 3.7

Other 16 9.9

From Table 1 and Table 2, it is conjectured that

students and company employees who are 10 to 49

years old have many interests in this service.

Moreover, about information source of this ser-

vice, shown in Table 3, 45.7% is news site, 14.8%

is someone’s Web site, 13.0% is search engine, thus

it is understood that the user who knew this service

WEBIST 2009 - 5th International Conference on Web Information Systems and Technologies

574

Table 3: Result of the questionnaire about information

source of this service.

Corcumstamce Number Percentage(%)

Newspaper 14 8.6

News site 74 45.7

Informed from friend 6 3.7

Search engine 21 13.0

Someone’s Web site 24 14.8

Other 23 14.2

from Web site accounts for about 73%. About the us-

age condition of this service, the frequency of the use

from this service’s Web site and from the toolbar are

1124 times and 572 times respectively.

Concerning the target for the existence proof, por-

tal site, news site, company’s site, weblog site, bul-

letin boards, shopping site and auction site are targets

of this service. It is thought that Web user’s interest is

high. Especially, about the existence proof by using

the toolbar, there are a lot of usage for the site where

the update frequency is high, such as the weblog, the

news site, auctions, and the shopping sites.

For more practicable service and the expansion of

the usage, it is necessary to construct the mechanism

that enable to use this service on various sites directly.

4.2 Non Users of the Existence Proof

Service

In order to research the potential user’s needs for the

service that acquires grounds of the existence of the

Web page, the questionnaire survey was conducted to

people who had not used the existence proof service.

Investigation objects are 32 people in their twenties,

and all members have the experience of using some

Web services but have no technical knowledge.

First, the objects were asked why they use the Web

services. The result is shown in Figure 4. The remark-

able reasons were “quick”, “convenient”, and “easy”.

From this result, it is conﬁrmed that people use the

Web service because it is simple and easy to use even

if they do not have any technical knowledge.

Secondly, the objects were asked what kind of

Web service they use. The result is shown in Table

5. Though The usage of the movie sharing site is re-

markable, the other Web services are used in almost

the same extent, hence it is considered that each Web

service is used on average.

The last question was about the needs of the exis-

tence proof service. Result is shown in Table 6. About

25% of the objects wanted to use the service, though

about 70% answered that they would not use the ser-

vice. From this result, the potential users do not think

Table 4: Result of question1 : “Why do you use the Web

services?”.

Answers

Number

Information is obtained quickly.

It is convenient

It is easy.

Desired information can be acquired.

Because of the use of the Weblog or

SNS.

Information is new.

It is easy to obtain information.

It is interesting.

Killing time.

The wanted thing can be obtained

cheaply.

Information all over the world is avail-

able.

Other

Table 5: Result of question2 : “What kind of the Web ser-

vice do you use?”.

Answers Number

Weblog 17

SNS 16

Individual homepage 14

Bulletin board 11

Movie sharing site 22

Auction 7

Shopping site 13

News site 13

Other 1

that they have signiﬁcant need to use the service to

proof the existence of the Web page.

Table 6: Result of question3 : “Do you want to use the

Existence proof service of the Web pages?”.

Answers Number Percentage(%)

Yes, I do. 8 25

No, I don’t. 19 60

I don’t need to use. 2 6

I have no idea. 3 9

From the result above, it can be conﬁrmed that

the ordinary users do not have so much considera-

tion about the risk when they use the Web service,

and they also do not feel the necessity of our service

very much. The objects who want to use the exist-

ing proof service mostly use SNS and movie shar-

ing site a lot, and the objects who do not want to use

the service mostly use the weblog and movie sharing

site. And there were some opinions that it is both-

THE EXISTENCE PROOF SERVICE OF THEWEB PAGES - New Web Service to Get Grounds of the Existence of the

Web Pages

575

eresome to use the Web service while considering the

risk and the way to use the existence proof service

is too complicated. Consequently, the existence proof

service is supposed to have the mechanism that is eas-

ily available on the SNS, the weblog, and the movie

sharing site. For instance, the mechanism to acquire

the grounds of the existence of the Web page that the

service periodically checks the requestedWeb site au-

tomatically and provides the notiﬁcation if there is a

change is considered.

5 CONCLUSIONS

“The existence proof service on the Web pages” was

released to the public. This service generates the

cache of the Web page and adds the time stamp to the

cache. By using the obtained data, it can be proven

that theWeb page existed in a certain URL at a certain

time and the cache has not been falsiﬁed. Moreover,

from the result of the questionnaire and the service

operation results, it is inferable that the users have

high interest about this service.

In this service, the cache includes HTML, CSS,

and image ﬁles. The cache can be preserved including

information that cannot be conﬁrmed by the displayed

appearance on a browser, such as the link information,

meta information, and so on. Therefore, this data can

be used for the perpetuation of evidence for the mis-

representation of the link. Moreover, because the dif-

ference of the appearance can be conﬁrmed by dis-

playing the cache on various browsers, information

that is more various than only the preservation of the

screenshot can be maintained.

In the future, the reliability securing on the Web

page, the compliance measures of the enterprise, and

the user protection are supposed to be achieved, by

developing the protocol of proof of sessions and API

of this service.

Concretely, the existence proof service can be set

up on various shopping sites, corporate sites, and so

on, by developing API of present service, and it will

be possible to contribute to the improvement of the re-

liability maintenance of the Web sites. For the enter-

prise that sells the product and service, it is expected

that using this service positively becomes an appeal

for the reliability of the site. Moreover, for users, they

can devise acountermeasure to the problem that oc-

curs while using the Web services.

In order to improve the reliability of the existence

proof service, the establishment of the standpoint as

the third-party institution by the cooperation of the

municipality and the ofﬁcial organnization is one of

the future tasks. And for the stability of the service,

consideration about the system performance and the

load tolerance is necessary.

ACKNOWLEDGEMENTS

This work was partially supported by the JSPS Grant-

In-Aid no.18300027.

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