Content Protection Method to Control Editing by Billing
Tomohiro Kobayashi
1
, Keiichi Iwamura
1
and Masaki Inamura
2
1
Faculty of Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
2
Center for Research and Collaboration, Tokyo Denki University, 5 Senju-Asahi-cho, Adachi-ku, Tokyo, 120-8551, Japan
Keywords: Copyright Protection, Content Protection, Edit Control, Digital Signature, Aggregate Signature, Billing.
Abstract: In consumer-generated media (CGM), where consumers themselves generate and transmit content, it is
important to promote secure content circulation. Content circulation includes the editing of content, and it is
desirable for content to become more abundant and varied. For copyright protection suitable for CGM, a
technology (Katsuma et al., 2015, Tatsuya et al., 2016) has been proposed that controls editing using digital
signatures, and guarantees the copyright of the original content even for secondary use. However, in those
scheme, the content that the author has declared as editing-prohibited once is always kept as editing-prohibited
thereafter, and the circulation of the content is stagnant from then onwards. Therefore, we propose a method
in which the author can securely provide individual editing permissions for content that has been sent as
editing-prohibited. Specifically, when an author wants to transmit content as editing-prohibited, and then an
editor wants to view it and purchase the right to edit the content, this method offers a way to securely buy and
sell the right to edit content in exchange for money. Therefore, this method is applicable to commercial content
circulation. It is possible to promote content circulation while protecting the rights of the author by using the
proposed method, even in scenarios where content circulation is stagnant with conventional methods.
1 INTRODUCTION
With the development of the Internet, it has become
easy to generate and transmit content, and the
distribution of content by general users has grown in
popularity. The media created by consumer is called
consumer-generated media (CGM). In CGM
(YouTube, Nico Nico Douga, etc.), it is easy to
browse and obtain published content with content
distribution services, so that new content can be
generated by secondarily using content. Content
circulation is promoted by creating better content, so
it is essential to have copyright protection technology
that can protect the rights of the original author
without interfering with content circulation. There is
also a need for technology to guarantee the copyright
of the original content.
A copyright protection method suitable for such
CGM has been proposed (Katsuma et al., 2015) and
(Tatsuya et al., 2016). In case of the former, content
control that combined editing control and rights
inheritance notation using a Boneh–Lynn–Shacham
(BLS) signature method (Boneh et al., 2001, Boneh
et al., 2003) was proposed. A method has been
proposed: The content was divided into multiple
content parts, and editing control was applied (change,
addition, deletion) to each content part, as was control
of appropriation of partial content to other content,
and control of content composition. Also, in case of
the latter, the use of ID-based signature methods (Xun,
2003, Jing et al., 2005) eliminated the need for public
key certificates and reduced the time needed for
signature verification in content produced by a large
number of authors and editors. As a result, with
regard to content for which the author has prohibited
editing, the rights of the author are protected and the
document is protected from further editing.
On the other hand, during content circulation, the
author's rights are regarded as important, and this
directly impacts the author's interests, that is, in a
situation where the author's rights are guaranteed, the
author can find profit and usually allows editing. It is
possible that editing rights are bought and sold for
content, so a technology is needed to allow the buying
and selling of editing rights for content with a
financial transaction. Therefore, in this paper, we
propose a means to safely permit editing only to the
purchaser in the above conventional method.
196
Kobayashi, T., Iwamura, K. and Inamura, M.
Content Protection Method to Control Editing by Billing.
DOI: 10.5220/0007959701960208
In Proceedings of the 16th International Joint Conference on e-Business and Telecommunications (ICETE 2019), pages 196-208
ISBN: 978-989-758-378-0
Copyright
c
2019 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved
In this paper, Section 2 describes previous
research, Section 3 describes an outline and the
algorithm of the proposed method, and Section 4
presents the conclusion.
2 PREVIOUS RESEARCH
2.1 Principle of Editing Control using
Signature
A technique has been proposed to control the
secondary usage of content using BLS signatures
(Katsuma et al., 2015, Tatsuya et al., 2016). The
author divides the content into multiple parts,
generated a digital signature in advance (hereinafter
referred to as an edit control signature) to indicate
whether or not editing is possible for each part, and
aggregate the edit control signature into one
(hereafter referred to as an aggregate signature). In
addition, the author disclose those aggregate
signatures of each piece of content. The author could
control in advance whether or not editing was
possible by concealing the control signature of the
partial content for which editing was not permitted,
and protecting it from being deleted. In this way, the
author could control in advance whether editing was
possible. In addition, it was possible to control
addition (change from empty data to actual data) and
deletion (change from actual data to empty data)
using control data that was not displayed as empty
data, and data that was displayed as actual data. The
content reproduction device had a signature
verification function, which it used to perform
signature verification before reproduction, and did
not reproduce content that did not have a valid digital
signature, or that did not match the digital signature
(was considered illegal).
In addition, a content administration center would
be established to verify the originality of each piece
of partial content and issue a digital signature
(hereinafter called the administration signature) to
certify the author. Set the administration signature
would be mandatory for partial content. With this
signature, each piece of partial content is linked to the
author, and it would be impossible to forge the author
of partial content (partial content without an
administration signature is considered to be illegal).
In addition, the author alone can be given the right to
edit (an edit control signature is always checked with
the author's key specified in the administration
signature), and any editing that the author does not
permit can be prohibited.
In addition, diversion control is realized by the
same mechanism described above, but using a content
ID, which will be described later. Here, a diversion
control signature is introduced to control diversion. It
is meaningless for the editor to change the signature
because the diversion control signature is
authenticated by the author's key of the original
content. Therefore, only the author (hereafter aID) of
the piece of partial content can decide the propriety of
diversion, and the diversion control signature is
always checked along with the aID key, so the editor
cannot change the setting.
In addition, composition control is control of
content that incorporates partial content, while editing
and diversion control is control of partial content.
Therefore, the process of ordering and arranging
multiple pieces of content, and considering it as one
piece of content is called composition of content, and
content generated by composition is called composi-
tion content. Here, we introduce a composition control
signature to control the composition of content. The
composition content is composed of structure data
(control data representing the order of content and
composition history) and a plurality of content
constituting the composition content. In addition, only
the author (hereafter cID) of the content can decide
whether or not to combine content, and cannot be
realized even if the author wants to leave the decision
of whether to combine or not to an editor.
2.2 Content and Partial Content, and
Structure of Aggregate Signature
Partial content is divided into two parts, real data and
control data; real data is treated as data to be displayed
as content, and control data is treated as non-displayed
data. The control data includes start data representing
the beginning of the content, final data representing the
end, empty data for controlling addition/deletion, and
structure data for controlling the composition of the
content. The content consists of start data, final data,
and one or more pieces of partial content created by the
author. In addition, the content ID is set for the content
as author information, and the partial content ID is set
for the partial content. As a result, it is possible to
perform change/addition/deletion control for each
piece of partial content, and also diversion control
within one piece of content, and also enable the
composition control of content.
Also, an edit control signature is generated for
each piece of partial content, and an aggregate
Content Protection Method to Control Editing by Billing
197
signature, in which the edit control signature is
aggregated, is set for the content. The aggregate
signature has the structure "start position signature +
edit control signature group of partial content + final
position signature." Here the start position signature
and the final position signature are always non-
disclosure. The structure of the start position
signature and the final position signature will be
described later. The aggregate signature is linked to
the start data or the final data for each piece of content
and disclosed, and content without an aggregate
signature is treated as illegal content.
2.3 Content Tree Structure
When a certain author creates content
,
is set
as the content ID. Furthermore, when the content
has partial contents
～
,
is set as the
start data,
is set as the final data, and
～
is set as the content ID. (i, j) of
represent
the position relationship of the content by the author,
so taking the position relationship shown in Figure. 1
as an example, the content
～
is by author
～
, respectively. It is the primary content
created by
～
. Also, the author
,
refers to the author who combines primary content to
make the secondary content
,
, and the author
refers to the author who combines secondary
content to create the tertiary content
. However,
each piece of content is not necessarily created by
different authors. For example,
and
may be
by the same author. Therefore, the notation is
,
, but the actual IDs are the same.
Figure 1: Content tree structure.
3 OUTLINE OF THE PROPOSED
METHOD
3.1 Principle of Content Protection by
Billing
To correspond about billing, it is necessary for the
author of the original content to provide the purchaser
with editing rights to the content individually for
which editing is prohibited. The editing rights are
controlled by the disclosure and non-disclosure of
signatures, as described in 2.1. In other words, the
signature of the target partial content is disclosed to
give the purchaser a permission to edit. However, if
the signature of the partial content for which editing
is prohibited is disclosed to the purchaser, there is a
risk that the signature may be leaked from the
purchaser who obtained the signature. Therefore, we
introduce a purchaser data as a control data which can
specify the purchaser, and the signature of the
purchaser data is aggregated in the signature of partial
content which the editor wants to edit. If the
purchaser is disclosed the signature of the partial
content, the purchaser data is also disclosed. If the
purchase data does not be added in the content, the
aggregate signature not in agreement. Therefore, the
purchaser who leaks the signature is determined. The
purchaser data is shown in Figure.2.
3.2 Partial Content Configuration
In addition to the actual data, empty data, start data,
final data, and structure data described in Section 2.2,
purchaser data is introduced as new control data in
order to control billing correspondence with the
purchaser. The purchaser ID is inserted into the
header of the purchaser data, and the information in
the billing correspondence described later is specified
in the partial content. Also, if the data is not purchaser
data , the purchaser ID is not set.
Therefore, as shown in Figure. 2, partial content
is associated with the original content author ID (aID),
content ID, partial content ID, purchaser ID, identifier,
administration signature, various edit control
signatures (change/deletion), diversion control
signature, composition control signature, etc. Here,
the content ID is an ID set by the author cID of the
content, and generally only one content ID (different
content IDs only when diversion control is
performed) is set to the content. However, the
composition control signature of pieces of partial
content other than start data and final data is not set.
Also, if editing is not possible, the hash value at that
time is linked to the bID (ID of the user who carried
out edit when prohibited) that has been disabled. Also,
if diversion is not possible, the hash value is associated
at that time. However, the identifier identifies data
types such as actual data, empty data, start data, final
data, structure data, and purchaser data.
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198
Author aID Content ID
Partial
content
Partial content ID Purchaser ID
Change control signature
bID
or Hash value
Deletion control signature
bID
or Hash value
Diversion control signature
or Hash value
Composition control signature
Identifier
Administration
signature
Others
Figure 2: Partial content configuration.
3.3 Algorithm
Based on the algorithm proposed in (Katsuma et al.,
2015) and (Tatsuya et al., 2016), the modified
algorithm to support the proposed method is shown
below.
3.3.1 Preparation and Key Generation
(1) Generation of Signature Key and Public Key.
Author
who generates the signature
requests the secret key issuance center to generate
the signature key. The secret key issuance center
selects ∈
as a generator, selects a random
number ∈
∗
, and the public key
=
(
) is calculated from the
, and
=
is issued as the signature key (secret key) of
author
.
(2) Publishing of
.
The secret key issuance center publishes
=
, where is the master secret key, and the
secret key issuance center keeps it secret.
3.3.2 When Creating Original Content
Author
define change / deletion / diversion
availability of partial content , content composition
availability and content ID and partial content ID
(here, partial content
～
～
is created,
and those partial content ID are defined as
～
～
) and do the following. Here, let
be the
partial content that corresponds to the credit for the
work, and
be the partial content for commercial
use judgment.
(1) Creation of Start Data and Final Data.
The control data
∗
,
∗
attached to the
head and tail of the content are created, and the
start position signature
and the final position
signature
are generated for each of change,
deletion, diversion and composition. Here, d is
empty data,
is a random number generated by
author
, and is a constant determined
according to the process, and change is
,
deletion is
, diversion is
, and composition
is
.
∗
=
||
||
∗
=
||
||
(1)
=
(
||
||
∗
||)
,
=
=
(
||
||
∗
|
|
)
,
=
(2)
(2) Creation of Control Data.
Based on the partial content
(d in the case
of empty data), control data
∗
is created.
∗
=
||
||
(3)
(3) Creation of Edit Control Signature.
A different constant is created for each edit,
and a hash value is generated.
ℎ
=(
||
||(
∗
)|
|
)
(4)
Also, the following hash values are calculated to
create the pre-composition and post composition
control signatures, where the constant is
for
pre-composition, and
for post-composition.
Pre-composition control hash value:
=(
||
||(
∗
)||
) (5)
Post-composition control hash value:
ℎ
=(
||
||(
∗
)||
) (6)
The following is calculated for each partial
content, where the random number
is
different for each edit.
Change control signature:
=
ℎ
+
,
=
(7)
Deletion control signature:
=
ℎ
+
,
=
(8)
Diversion control signature:
=
ℎ
+
,
=
(9)
Pre-composition control signature:
=
ℎ
+
,
=
(10)
Post-composition control signature:
=
ℎ
+
,
=
(11)
Content Protection Method to Control Editing by Billing
199
(4) Aggregate Signature of Content.
Aggregate signatures for various controls are
created. Here,
,
,…,
,
are
different for each editing.
Change aggregate signature:
=
+
∑
+
,
,
,…,
,
(12)
Deletion aggregate signature:
=
+
∑
+
,
,
,…,
,
(13)
Diversion aggregate signature:
=
+
∑
+
,
,
,…,
,
(14)
Composition aggregate signature:
=
+
+
+
,
,
,
,
(15)
(5) Linking to Partial Content.
The partial content for which editing is permitted
is associated with the generated edit control
signature. For the partial content for which editing
is prohibited, the hash value used for signature
creation is linked to the partial content, and author
bID links to the author of the original content.
3.3.3 Change, Addition, Deletion, Diversion
of Partial Content
Consider the case where author
edits (changes,
adds, deletes, diverts) the partial content
of the
content
and sets it as the partial content
.
At this time, author
performs the following
process. When editing two or more pieces of partial
content, the process is repeated.
(1) Signature Verification of Secondary Use
Content.
Confirm that the signature of content
is
verified. Here, partial content for which diversion
is permitted can be diverted, and partial content
for which change / addition / deletion is
permitted can be changed to partial content
.
(2) Generation of Hash Value.
Author
creates control data
∗
from the
edited partial content
, and creates a hash
value and a part of the control signature as in
Section 3.3.2 (3).
∗
=
||
||
(16)
ℎ
=(
||
||(
∗
)||) (17)
(3) Aggregate Signature Update.
Author
creates a control signature from
in the same manner as in Section 3.3.2 (3),
and creates each edit control signature from the
signature key
of author
and the
constant
generated by author
.However,
if no change is permitted, it cannot be changed.
The aggregate signature is updated as follows
(
is replaced with
).
Change aggregate signature:
=
−
+
,
,
,…,
,
(18)
Deletion aggregate signature:
=
−
+
,
,
,…,
,
(19)
Diversion aggregate signature:
=
−
+
,
,
,…,
,
(20)
Also, for prohibited edits (change / addition /
deletion), the aggregate signature is not updated.
(4) Linking to Partial Content.
Partial content that permits editing is associated
with an editing control signature. Also, for partial
content that prohibits editing, only the generated
hash value and
are linked to the partial
content, and author's
is linked as author
bID for which editing is prohibited.
3.3.4 Content Composition
When author
combines content
and
as the front and back content, author
performs
content composition according to the following
procedure.
(1) Signature Verification of Secondary Use
Content.
Author
checks whether the post-
composition control signature of content
and
the pre-composition control signature of
are disclosed, and verifies the aggregate signature.
If both
and
are permitted to be
combined, author
can combine them, and
at this time, record the combined order of
and
in the structure data.
If the content that composes the composition
content is composable, the content side of the
content front and back that is also composable, so
it is possible to delete the content. Therefore, new
content can be composited at that position. In
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200
addition, even if the first or last piece of content
in the composition content cannot be combined,
even if the side without the content cannot be
combined, if the side with the content can be
combined, the content can be deleted and replaced.
3.3.5 Signature Verification
Content signature verification is always performed by
the playback device when using content
(viewing/secondary use). Here, the object that
performs content signature verification is called a
verifier, and the verifier performs the following
processing.
(1) Verification of Administration Signature.
The verifier verifies whether the administration
signature of each piece of partial content is valid.
Partial content without an administration
signature, or with inconsistent content is regarded
as illegal content.
(2) Verification of Composition Content.
In the case of composition content, this refers to
structure data and separates the composition
content into pieces of content. If the structure of
the structure data and the structure of the content
do not match, the content is considered as illegal
composition.
(3) Verification of Composition Control Signature.
The verifier verifies that each content is
composited correctly as follows using the public
key,
, of aI D.
,
=
∏
,ℎ
(
,
) (21)
(4) Verification of Diversion Control Signature.
I. The verifier verifies that each piece of partial
content is correctly used and verifies the use of a
public key
as follows.
,
=
∏
,ℎ
(
,
) (22)
II. Confirmation of Content ID.
The verifier verifies whether each partial
content has the correct content ID (content ID
is unified). If they have different content IDs,
the following is performed for the target
partial content.
(ⅰ) When the Diversion Control Signature
is Disclosed:
It is verified as follows using the public
key
of aID whether the diversion
control signature of partial content is
correct or not.
,
=
,ℎ
(
,
) (23)
(ⅱ) When the Diversion Control Signature
is not Disclosed:
It verifies whether the generated hash
value and the diversion hash value are
equal.
(5) Verification of Control Signature of Each Edit.
The verifier confirms that each piece of partial
content is correctly edited (change / addition /
deletion). First, it checks whether the empty data
is in a changeable/deletable or non-
changeable/non-deletable state, and the verifier
generates a hash value for each edit. If the actual
data does not have a change control signature, the
verifier confirms that the generated hash value
and the change hash value are equal. If the empty
data does not have a deletion control signature, it
confirms that the generated hash value and the
deletion hash value are equal. The verifier uses the
public key
of aID (the public key
,
and the signature
,
if the
changeable/deletable has been changed), the hash
value of the generated partial content, and the
partial content without a signature to collect the
hash values attached and verifies that the
following equation holds true.
,
=
∏
,ℎ
(
,
) (24)
,
=
∏
,ℎ
(
,
) (25)
3.4 Content Protection by Billing 1
In the proposed method, the signature of the partial
content to be purchased is not disclosed
independently as described above, but an aggregate
signature is created and disclosed by aggregating the
purchaser data described in 3.1 and the partial content
to be purchased to the user.
First, the content created by the author of the
original content is composed of partial content
～
(
: Start data;
,
: Actual data
with editing prohibited;
,
: Empty data;
: Final data). At this time, the billing mechanism
for various editing controls is explained in Sections
3.4.1 to 3.4.3, taking the case where the purchaser
purchases editing rights for editing partial content as
an example.
In addition, by disclosing the signature to the
purchaser as follows, it is possible to allow the
purchaser to edit it without disclosing the partial
content signature, and the purchaser can create a valid
aggregate signature for the edited content.
In addition, the signature
of the purchaser
Content Protection Method to Control Editing by Billing
201
data
in which the purchaser ID (dID) is
inserted in the header is aggregated into the aggregate
signature disclosed to the purchaser dID. By doing so,
the purchaser must add purchaser data
in order
to properly edit the partial content. Therefore, in order
to leak the aggregate signature
received by the
purchaser, it is necessary to pass the purchaser data
aggregated together with the partial content
signature. Therefore, because the leak source is
known, it is possible to prevent the intentional
signature leak by a malicious purchaser.
3.4.1 Content Protection by Billing 1
(Change / Addition / Deletion Control)
The algorithm for billing for various edit controls is
shown below.
Change Control. In the change control, the content
is controlled using the change control signature. The
billing correspondence in the change control will be
described below by taking an example of allowing
change of the actual data
, in the content shown
in 3.4 to actual data
. In addition, because it is
necessary to add purchaser data simultaneously with
the change of the partial content to be purchased in
the proposed method, empty data A
is also
changed to purchaser data A
at the same time.
Change aggregate signature of content
is
constructed as follows.
=
+
+
+
+
+
(26)
(1) Author aID creates a purchaser data
using
a purchaser ID (dID), and creates a change
control signature
for the purchaser
data
.
(2) A change aggregate signature
is created using
the change control signature
of actual data
, the change control signature
of
purchaser data
, and the change control
signature
of the empty data
that is
used for the addition of the purchaser data
.
=
+
−
(27)
(3) Purchaser dID changes actual data
to actual
data
, and adds empty data
to
purchaser data
, and then adds aggregate
signature
, change control signature
of
actual data
, and creates a post-edit change
aggregate signature
′
using the pre-edit
change aggregate signature
.
′
=
−
+
=
+
+
+
+
+
(28)
Addition Control. "Addition" indicates a change
from empty data to actual data. Therefore, it can be
realized by performing control using a change control
signature in the same manner as change control, and
requesting the right to edit empty data
instead
of actual data
in the above “Change control”.
Deletion Control. Deletion indicates a change from
actual data to empty data, but unlike the change /
addition control, a deletion control signature is used
to realize a state such as {changeable and non-
deleteable or non-changeable and deleteable}. The
billing correspondence in the deletion control will be
described below by taking an example of allowing
change of actual data A
, in the content shown in
3.4, to empty data A
and deleting it. In addition,
because it is necessary to add purchaser data
simultaneously with the deletion of the partial content
to be purchased in the proposed method, the update
of the change aggregate signature is also performed
simultaneously. Therefore, empty data
is also
changed to purchaser data
at the same time.
The change aggregate signature
of content, and
the deletion aggregate signature
are configured
as follows:
=
+
+
+
+
+
(29)
=
+
+
+
+
+
(30)
(1) Author aID creates purchaser data
using a
purchaser ID (dID), and creates a change control
signature
and a deletion control signature
for purchaser data
.
(2) I. A deletion aggregate signature
is created
using the deletion control signature
of
actual data
, the deletion control signature
of purchaser data
, and the deletion
control signature
of empty data
that is used for the addition of purchaser data
.
=
+
−
(31)
II. A change aggregate signature
is created
using change control signature
of
purchaser data
and change control
signature
of empty data
that is
used for the addition of purchaser data
.
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=
−
(32)
III. The deletion aggregate signature
, the
change aggregate signature
, and
purchaser data
created above are
disclosed to the purchaser.
(3) The purchaser dID deletes actual data
by
changing it to empty data
, and adds empty
data
by changing it to purchaser data
, and performs the following steps.
I. Update of Deletion Aggregate Signature.
A post-edit deletion aggregate signature
′
is created using the deletion aggregate
signature
, deletion control signature
of empty data
, and pre-edit deletion
aggregate signature
.
′
=
−
+
=
+
+
+
+
+
(33)
II. Update of Change Aggregate Signature.
A post-edit change aggregate signature
′
is created using the change aggregate
signature
and pre-edit change aggregate
signature
.
′
=
−
=
+
+
+
+
+
(34)
3.4.2 Content Protection by Billing 1
(Diversion Control)
Diversion means adding actual data from one content
to other content. Therefore, in diversion, the piece of
partial content for the diversion destination is
changed and added, so the change aggregate signature
is needed to be also updated simultaneously. In the
explanation, the content shown in 3.4 is used as
content 1 of the diversion source created by the author,
and content 2 of the diversion destination is newly
defined and used below. Here, content 2 of the
diversion destination is the content composed of
partial content
～
(
: start data;
:
actual data;
,
: empty data,
: final data).
In addition the diversion control signature
,
,
and change control signature
,
,
of empty data
,
,
of
the diverted destination are assumed to be disclosed.
Diversion aggregate signatures,
,
, and change
aggregate signatures
,
of Content 1 and
Content 2 are configured as follows.
=
+
+
+
+
+
(35)
=
+
+
+
+
(36)
=
+
+
+
+
+
(37)
=
+
+
+
+
(38)
(1) Author aID creates purchaser data
using
a purchaser ID (dID), and creates a change control
signature
and a diversion control signature
for the purchaser data
.
(2) I. Diversion aggregate signature
is created
using diversion control signature
of
actual data
, and diversion control
signature
of purchaser data
.
=
+
(39)
II. Change aggregate signature
is created
using change control signature
of actual
data
, and change control signature
of purchaser data
.
=
+
(40)
III. Disclose diversion aggregate signature
,
change aggregate signature
, and
purchaser data
created above to the
purchaser.
(3) The purchaser dID diverts empty data
to
actual data
, adds empty data
to
purchaser data
, and performs the following
steps.
I. Update of the Diversion Aggregate Signature.
Post-edit diversion aggregate signature
′
is created using diversion aggregate signature
, diversion control signatures
,
of
empty data
,
, and pre-edit diversion
aggregate signature
.
′
=
+
−
−
=
+
+
+
+
(41)
II. Update of the Change Aggregate Signature.
Post-edit change aggregate signature
′
is created using change aggregate signature
, change control signatures
,
of
empty data
,
, and pre-edit change
aggregate signature
.
′
=
+
−
−
=
+
+
+
+
(42)
3.4.3 Content Protection by Billing 1
(Composition Control)
In the description, content 1 is defined as the author's
created content, and content 2 is defined as the
composition target content using content 1 and
content 2, as in 3.4.2. Here, it is assumed that pre-
combination control signature
of start data
Content Protection Method to Control Editing by Billing
203
of content 2 is released.
(1) Author aID creates purchaser data
using a
purchaser ID (dID), newly creates start data
and final data
, and creates content that is
composed of partial content
,
,
(
: start data,
: purchaser data,
:
Final data) and this is called content 3. In addition,
the various control signatures are created in the
same manner as discussed in 3.3, and aggregate
signatures for various edit controls of content 3
are created.
(2) Content 1 and content 3 are composed using post-
composition control signature
of content 1,
and pre-composition control signature
of
content 3 so it is in the order 1 → 3 to create
composition content 1 – 3. At the same time,
structure data is created so it is in the order 1 →
3. Then, Author aID disclose post-composition
control signature
of composition content 1–
3 and content 3 to the purchaser.
(3) The purchaser dID uses the post-composition
control signature
of the content 3 and the
pre-composition control signature
of the
content 2 to compose the content 3 side of the
composition content 1-3 and the content 2.
By disclosing the signature to the purchaser as
described above, the composition control signature of
content 1 is not disclosed, but the composition control
signature of content 3 composed of purchaser data
is disclosed to the content of purchaser 1. It is
possible to indirectly allow the composition of
content 2. Further, because content 1–3 includes the
purchaser data
, when the purchaser tries to leak
the composition control signature of content 3
received, the leakage source is identified from the
purchaser data
of the content 3. Therefore, it is
possible to prevent intentional signature leakage by a
malicious purchaser.
3.5 Content Protection by Billing 2
In billing method 1 described in 3.4, the author of the
content must perform the above processing each time
a purchaser appears. Therefore, if the number of
purchasers increases, the author's burden is large.
Therefore, assuming that the purchaser performs the
processing in advance assuming that the third party is
the one that collectively manages copyrights such as
JASRAC, the third party performs the processing at
the time of the billing correspondence. We propose a
method of entrusting to an institution as billing
method 2.
First, in order to entrust the billing
correspondence to a third-party organization, the
author of the content discloses signature for the
billing correspondence to the third-party organization
in advance. At this time, there is also a possibility that
the signature leaked from a third-party organization,
so that the measures should be taken at the same time.
The mechanism of the billing correspondence for
various edit controls in billing system 2 will be
described below in 3.5.1 to 3.5.3.
Also, by making the signature disclose to the
purchaser via a third-party organization as follows,
while the burden on the author is reduced, it becomes
possible to allow the purchaser to edit as in the case
of billing system 1. However, purchaser data
, in
which the third-party organization ID (eID) is
inserted into the header is aggregated in the aggregate
signature disclosed to the third-party organization
eID. In order to edit partial content when doing so, it
is necessary to add purchaser data
, and when the
third party tries to leak the aggregate signature
received, it is integrated with the partial content
signature. The leak source is identified from
purchaser data
. Therefore, it is possible to
prevent intentional signature leakage by malicious
third parties.
In addition, to realize editing permission by any
purchaser for a third-party organization, aggregate
signature
is configured in advance so that the
third-party organization can add purchaser data
for the purchaser dID. As a result, the third party can
construct an aggregate signature
that includes
purchaser data
using aggregate signature
received from the author. Therefore, to edit partial
content, it is necessary to add purchaser data
.
Thus, to leak aggregate signature
received by the
purchaser, it is necessary to pass purchaser data
aggregated together with the partial content signature.
Because the leak source is known, it is possible to
prevent the intentional signature leak by a malicious
purchaser.
3.5.1 Content Protection by Billing 2
(Change/Addition/Deletion)
Below is an algorithm for billing method 2 for various
edit controls (change, addition, deletion).
Change Control. The charge correspondence in the
change control will be described below, taking the
case of changing actual data
to actual data
as an example. The change aggregate signature
ICE-B 2019 - 16th International Conference on e-Business
204
of the content is configured as follows.
=
+
+
+
+
+
(43)
(1) Author aID creates purchaser data
using a
third-party organization ID (eID), and creates a
change control signature
for purchaser data
.
(2) Change aggregate signature
is created using
change control signature
of actual data
, change control signature
of purchaser
data
, and change control signatures
,
of empty data
,
that are
used for the addition of purchaser data
,
. In addition, disclose
to a third
party with the purchaser data
.
=
+
+
−
(44)
(3) Third-party organization eID creates purchaser
data
using purchaser ID (dID) and creates
a change control signature
for purchaser
data
.
(4) Change aggregate signature
is created using
change aggregate signature
and change
control signature
of purchaser data
,
and is disclosed to the purchaser together with
purchaser data
,
.
=
−
=
+
+
−
−
(45)
(5) The purchaser dID changes the actual data
to actual data
, and adds empty data
,
to the purchaser data
,
, and
then adds the change aggregate signature
and
the actual data
. Create a post-edit change
aggregate signature
′
using the change
control signature
and the pre-edit change
aggregate signature
.
′
=
−
+
=
+
+
+
+
+
(46)
Addition Control. As described in 3.4.1, addition
control is performed using a change control signature,
and this can be realized by exposing the editing right
of empty data instead of that of actual data in 3.5.1
“Change control”.
Deletion Control. The billing correspondence in
deletion control will be described below by taking
actual data
as empty data
and deleting as
an example. It is assumed that the content change
aggregate signature
and deletion aggregate
signature
are configured as follows.
=
+
+
+
+
+
(47)
=
+
+
+
+
+
(48)
(1) Author aID creates a purchaser data
using
a third-party organization ID (eID), and creates a
change control signature
and a deletion
control signature
for the purchaser data
.
(2) I. A deletion aggregate signature
is created
using the deletion control signature
of
actual data
, the deletion control
signature
of purchaser data
, and
the deletion control signatures
,
of
the empty data
,
that is used for the
addition of the purchaser data
,
.
=
+
+
−
(49)
II. The change aggregate signature,
, is created
using change control signature
of
purchaser data
, and change control
signature
,
of empty data
,
for adding purchaser data
,
.
=
+
−
(50)
III. The deletion aggregate signature
, the
change aggregate signature
and the
purchaser data
created above are
disclosed to a third-party organization.
(3) Third-party organization eID creates purchaser
data
using purchaser ID (dID), and creates
change control signature
and deletion
control signature
for purchaser data
.
(4) I. Update of Deletion Control Signature.
A deletion aggregate signature
is created
using deletion aggregate signature
and
deletion control signature
of purchaser
data
.
=
−
=
+
+
−
−
(51)
II. Update of Change Control Signature.
A change aggregate signature
is created
using the change aggregate signature
and
change control signature
of the purchaser
data
.
=
−
=
+
−
−
(52)
III. The deletion of aggregate signature
, the
change aggregate signature
, and the
Content Protection Method to Control Editing by Billing
205
purchaser data
,
created above are
disclosed to the purchaser.
(5) The purchaser dID deletes actual data
by
changing it to empty data
, adds the empty
data
,
by changing it to the purchaser
data
,
, and performs the following steps.
I. Update of Deletion Aggregate Signature.
A post-edit deletion aggregate signature
′
is created using the deletion aggregate
signature
, the deletion control signature
of empty data
, and the pre-edit
deletion aggregate signature
.
′
=
−
+
=
+
+
+
+
+
(53)
II. Update of change aggregate signature.
A post-edit change aggregate signature
′
is created using the change aggregate
signature
and the pre-edit change
aggregate signature
.
′
=
−
=
+
+
+
+
+
(54)
3.5.2 Content Protection by Billing 2
(Diversion Control)
In the explanation, content 2 similar to 3.4.2 is newly
defined and used as the content 2 of the diversion
destination. Here, content 2 of the diverted
destination is content composed of partial content
～
(
: start data;
: actual data;
,
,
empty data, and
: final data).
The diverted destination is empty It is assumed that
diversion control signatures
,
,
and the
change control signatures
,
,
of data
,
,
are disclosed. The billing
correspondence in diversion control will be described
below, taking the case where actual data
of
content 1 is added to empty data
of content 2,
and diverted. It is assumed that diversion aggregate
signatures
,
and change aggregate signatures
,
of contents 1 and 2 are configured as follows.
=
+
+
+
+
+
(55)
=
+
+
+
+
+
(56)
=
+
+
+
+
+
(57)
=
+
+
+
+
+
(58)
(1) Author aID creates a purchaser data
using
a third-party organization ID (eID), and creates
change control signature
and diversion
control signature
for purchaser data
.
(2) I. Diversion control signature
of purchaser
data
and diversion control signature
of actual data
are used to create
diversion aggregate signature
.
=
+
(59)
II. A change aggregate signature
is created
using a change control signature
of
purchaser data
, and change control
signature
of actual data
.
=
+
(60)
III. change aggregate signature
and the
purchaser data
created above are
disclosed to a third-party organization.
(3) Third-party organization eID creates purchaser
data
using purchaser ID (dID), and creates
a change control signature
, and diversion
control signature
for data purchaser
.
(4) I. Update of Diversion Control Signature.
A diversion aggregate signature
is created
using diversion aggregate signature
and
diversion control signature
of purchaser
data
.
=
+
=
+
+
(61)
II. Update of Change Control Signature
A change aggregate signature
is created
using the change aggregate signature
and
the change control signature
of the
purchaser data
.
=
+
=
+
+
(62)
III. The diversion aggregate signature
, the
change aggregate signature
, and the
purchaser data
,
created above are
disclosed to the purchaser.
(5) The purchaser dID diverts empty data
to
actual data
, adds empty data
,
to
purchaser data
,
, and performs the
following:
I. Update of the Diversion Aggregate Signature.
After editing using the diversion aggregate
signature
, the empty data for adding
content 2
,
,
is diverted to
control signature
,
,
and the
pre-edit diversion aggregate signature
to
create the post-edit diversion aggregate
signature
′
.
ICE-B 2019 - 16th International Conference on e-Business
206
′
=
+
−
−
−
=
+
+
+
+
+
(63)
II. Update of the Change Aggregate Signature.
Before editing, after change aggregate
signature
, change control signatures
,
,
of the empty data
,
,
for addition of content 2 and
the change aggregate signature
, create
the change aggregate signature
′
.
′
=
+
−
−
−
=
+
+
+
+
+
(64)
3.5.3 Content Protection by Billing 2
(Composition Control)
In the description, Content 1 is defined as the author's
created content, and Content 2 is defined as the
composition target content using Content 1 and
Content 2 as in 3.4.3. Here, it is assumed that the
composition control signature
of the start data
of content 2 is disclosed.
(1) Author aID creates purchaser data
using a
third-party organization ID (eID), and is
composed of partial contents
,
,
,
(
: start data;
:
empty data;
: Purchaser data (eID),
:
Final data). Furthermore, in the same manner as
in Section 3.3.2, various control signatures for
each partial content, and various aggregate
signatures for content 3 was obtained by
aggregating them.
(2) Composition content 1 and content 3 using the
post-composition control signature
of
content 1 and the pre-composition control
signature
of content 3 so it is on the order
of 1 → 3 to create the composed content 1–3
After that, the post- composition control signature
of the composited content 1–3, and content
3 and change control signature
of empty
data
of content 3 are disclosed to a third-
party organization.
(3) Third-party organization eID creates purchaser
data
using a purchaser ID (dID), and
creates change control signature
for the
purchaser data
. Then, using the change
control signature
of the empty data
and the change control signature
of the
purchaser data
, the change aggregate
signature
=
+
+
+
before
editing is updated. Therefore, the post-edit change
aggregate signature
′
is created by adding the
purchaser data
to the content 3.Then, post
composition control signature
of
composition content 1–3 and content 3 is
disclosed to the purchaser.
′
=
+
−
=
+
+
+
(65)
(4) The purchaser dID combines the content 3 part of
the composition content 1–3 with content 2 using
post-composition control signature
of
content 3 and precomposition control signature
of the content 2.
By disclosing the signature to the purchaser as
described above, while reducing the burden on the
author, it is possible to indirectly permit the
composition of content 1 by disclosing the composite
control signature of the content 3 composed of the
purchaser data. Furthermore, because composition
content 1–3 includes purchaser data
, when the
third party tries to leak the composition control
signature of the content 3 received, the leak source of
content 3 from the purchaser data
is revealed.
Therefore, it is possible to prevent intentional
signature leakage by malicious third parties.
4 CONCLUSION
In this method, for content for which the author has
prohibited editing, when an editor wants to have
permission to edit the content appears, billing is
performed as a content control method to allow the
purchaser editing permission through a financial
transaction. We proposed two response methods. The
first was a method to correspond to billing between
the author and the purchaser, but with the above
proposal method, if the number of purchasers
increase, the burden on the author would increase.
The second problem is that a third party is assumed
based on the measures taken when the burden of the
author is considered to be a problem, and the author-
third-party purchaser. However, even in the proposed
method, copyright management is concentrated in
one place, which leads to problems such as high risk
when assuming an attacker. In the future, considering
the proxy signature (Boldyreva et al., 2012, Xu et al.,
2005) etc. to address the above problems, we will
decentralize the agencies that billing correspondence
and reduce the risk of attacks, etc. Additionally, we
would like to perform research on technology.
Content Protection Method to Control Editing by Billing
207
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