[DESCRIPTION]

[Invention Title]

CONTENTS EXECUTION DEVICE EQUIPPED WITH INDEPENDENT

AUTHENTICATION MEANS AND CONTENTS RE-DISTRIBUTION

METHOD

[Technical Field]

The present invention relates to a content providing service method

used in digital broadcasting and a content execution device for the same, and

more particularly, to a digital content providing service method and a content

execution device for the same which maximize user convenience and maintain

a sufficient security level using a smart card.

[Background Art]

Digital content is of excellent quality and quite convenient to manage

compared to conventional analog content. However, since digital content can

be copied an unlimited number of times, the danger and possible extent of

infringement are great. In particular, in digital broadcasting, it is well known

that when easy-to-copy digital content is provided to many subscribers, wide

scale copyright infringement results. Accordingly, as protection of digital

content is rapidly regarded as being of great importance to the development of

digital industries, various formats of digital rights management (DRM) have

been developed.

As broadcasting service is digitalized, a slightly improved protection

mechanism is required. A conventional conditional access system (CAS)

cannot guarantee the security of broadcast content in emerging broadcasting

business models. For example, it cannot guarantee protection of broadcast

content from recording and re-distribution.

In a conventional broadcasting system, each of broadcasting station

servers (broadcasters) uses its own specific protection mechanism for a

broadcasting service, and does not have a protection mechanism compatible

with other broadcasting stations. Accordingly, if an end user intends to use a

new channel service from other broadcasters, he/she has to change his/her own

set-top-box (STB). This is very troublesome and costly to consumers of

broadcast content.

Further, in the case where the user replaces his/her set-top-box with

another one, he/she should reregister the new set-top-box with each

broadcasting station. This results in great inconvenience to the user.

In the meantime, a user lawfully receiving content may wish to use the

received content in devices other than a multimedia device used to receive the

content, or to re-distribute the received content to other users. However, the

conventional art does not permit such varied license distribution. This is a

limitation to the user in using the content, and may be an obstacle to the spread

of digital content broadcasting.

[Disclosure]

[Technical Problem]

The present invention is directed to strengthening of security and/or

enhancement of convenience in digital content distribution and management.

The present invention is also directed to a content execution device for

conveniently performing an authority authentication procedure using a smart

card.

Further, the present invention is directed to a method of efficiently

providing a broadcasting service using a smart card, in a broadcasting system

having a structure where authentication and tool management roles are

separated.

Furthermore, the present invention is directed to a method of

efficiently providing broadcasting service using a smart card, in a broadcasting

system where a broadcasting content consumer region is specified as a home

domain.

Furthermore, the present invention is directed to a method of

transmitting lawfully acquired content to other users or devices.

[Technical Solution]

One aspect of the present invention provides a content execution

device including: an independent authentication unit for storing a tool

necessary for executing content; a tool agent for calling the tool stored in the

independent authentication unit; and a content execution unit for executing

content data received from an external broadcasting server.

Another aspect of the present invention provides a content

broadcasting service subscription method performed in a content execution

device (also, called a user device to emphasize belonging to a broadcasting

service user side) and a broadcasting server broadcasting content data, the

method including the steps of: in the user device, requesting a broadcasting

station server for a new subscription; transmitting information of a user smart

card connected to the user device, to the broadcasting station server; in the

broadcasting station server, checking the received smart card information;

registering the new subscription and the smart card with the broadcasting

station server; in the broadcasting station server, transmitting a certificate to

the smart card; and in the smart card, storing the certificate in an internal

memory.

Yet another aspect of the present invention provides a content

execution method performed in a content execution device, the method

including the steps of: receiving content from a broadcasting station server;

determining a tool necessary for executing the received content; determining

whether or not the necessary tool exists in a smart card; connecting to a tool

server, and requesting the tool when it does not exist in the smart card;

receiving the tool from the broadcasting station server; storing the received

tool in the smart card; and executing the content using the tool stored in the

smart card.

Yet another aspect of the present invention provides a method for re¬

distributing content from a content execution device (source device) and to a

content execution device (target device), the method including the steps of:

checking whether or not re-distribution of the content is permitted;

transmitting the content, use tool information, and a point of the broadcasting

station server to the target device; in the target device, connecting to the

broadcasting station server and requesting permission to execute the content;

and receiving the execution permission, and playing the content.

Yet another aspect of the present invention provides a method for re¬

distributing content performed in a source device and a target device, the

method including the steps of: checking whether or not re-distribution of the

content is permitted; receiving authentication of the target device from an

external broadcasting server; transmitting the content, use tool information,

and play permission information to the target device; and in the target device,

playing the content.

Yet another aspect of the present invention provides a method for re¬

distributing content from a source device to a target device performed in the

source device, the method including the steps of: checking whether or not re¬

distribution of the content is permitted; receiving authentication of the target

device in an external tool server; and transmitting the content, use tool

information, and a pointer of a broadcasting station server holding rights to the

content, to the target device.

Yet another aspect of the present invention provides a method for re¬

distributing content from a source device to a target device performed in the

target device, the method including the steps of: receiving the content, use tool

information, and a pointer of the broadcasting station server from the source

device; connecting to a broadcasting sever holding rights to the content, and

requesting permission to execute the content; and receiving execution

permission, and playing the content.

Yet another aspect of the present invention provides a method for

conversional re-distributing content from a content execution device (source

device) to a portable device (target device), the method including the steps of:

checking whether or not conversional re-distribution of the content stored in

the source device is permitted; requesting a tool server for transmission of a

portable device tool (hereinafter, referred to as "portable tool"), and

downloading the portable tool; requesting a broadcasting station server for

permission to re-transmit the content to the target device, and receiving the

permission; transmitting content, portable tool, and the re-transmission

permission to a portable device; and in the target device, playing the content

using the portable tool, and the re-transmission permission.

Yet another aspect of the present invention provides a method for

conversional re-distributing content from a source device to an external target

device, the method including the steps of: checking whether or not

conversional re-distribution of the content is permitted; requesting an external

tool server for transmission of a portable tool, and downloading the portable

tool; requesting a broadcasting station server holding rights to the content, for

permission to convert and re-distribute the content, and receiving the

permission; and transmitting content, a portable tool, and the permission to re¬

transmit the content to the target device.

[Advantageous Effects]

As described above, in the present invention, a content execution

device included in a content authority management system of the present

invention employs the smart card for user authentication and/or content

playing tool management. Accordingly, a user can freely execute his/her

licensed content in different content execution devices by conveniently

removing and reinserting the smart card, without separate measures.

Moreover, according to the present invention, a user can effectively

use content from different broadcasters.

Thanks to a content re-distribution method of the present invention,

broadcasting non-subscribers also can execute broadcast content within a

limited range, thereby fostering widespread, lawful use of broadcast content.

According to the content re-distribution method of the present

invention, content protected by a copyright protection device can be executed

in different multimedia devices such as a PDA, as well as a content

broadcasting receiver, thereby fostering widespread, lawful use of broadcast

content.

[Description of Drawings]

FIG. 1 illustrates a structure of a content broadcasting system capable

of employing a content execution device according to the present invention;

FIG. 2 is a block diagram illustrating a structure of a content execution

device according to an embodiment of the present invention;

FIG. 3 is a block diagram illustrating a structure of a tool pack, which

can be applied to a content execution device according to the present

invention;

FIG. 4 is a block diagram illustrating a content providing service

method according to an embodiment of the present invention;

FIG. 5 is a block diagram illustrating a content service providing

method according to another embodiment of the present invention;

FIG. 6 is a block diagram illustrating a content service providing

method according to a further embodiment of the present invention;

FIG. 7 is a block diagram illustrating a content re-distribution method

according to an embodiment of the present invention;

FIG. 8 is a block diagram illustrating a content re-distribution method

according to another embodiment of the present invention; and

FIG. 9 is a block diagram illustrating a content re-distribution method

according to a further embodiment of the present invention.

* Description of Major Symbols in the above Figures

100 : Content execution device 110 : Authentication support module

120 : Tool agent 130 : Content execution unit

140 : Broadcast receiving stage 200 : Smart card

210 : Tool storage unit 220 : Authentication module

230 : Authority storage unit 300 : Broadcasting station server

400 : Tool server

[Mode for Invention]

For clarity, a digital content protection/management system capable of

employing the present invention will be described. A home domain system of

the present invention can be used together with various types of digital content

protection/management system. However, since the present invention does

not relate to a digital content protection/management system, the present

invention will be described with reference to a specific digital content

protection/management system.

The broadcast content protection/management system of FIG. 1

includes a producer server of a content provider; a transmission server 300-1

for transmitting content received from the producer server to respective

service subscribers; a clearing house 300-2 for authenticating the respective

subscribers and/or content; and a tool server 400 for managing tools for

encrypting/decrypting content data.

The producer server, which is a server for authoring information for

protecting/managing broadcasting content, takes charge of transmitting

content inlormation (protection stream) to be protected/managed to the

transmission server 300-1 in association with the tool server 400. In other

words, the producer server registers content to be broadcasted with the

clearing house 300-2, and receives information (e.g. a content ID, a clearing

house public key, and a clearing house URL) necessary for distribution.

Further, the producer server determines a tool to be applied to the content, and

receives tool information (a tool ID and a tool descriptor). In a case where the

tool server 400 does not have the tool to be applied, the producer server can

also register a new tool and a tool descriptor with the tool server 400 and be

allotted a new tool ID. Depending on DMP terminology, the producer server

can be operated as CP or SP.

The transmission server 300-1 serves to receive the protection stream

from the producer server, and transmit the received protection stream to a

domain controller (content execution device 100) of the service subscriber.

Depending on the embodiment, the protection stream can be converted to have

a predetermined format, and transmitted. Depending on the format embodied,

the protection stream can be also converted by the tool registered with the tool

server 400. In an embodiment where format conversion is made without using

the tool server 400, when the producer server prepares and transmits a syntax

file of distribution, tool, and storage information to the transmission server

300, it can also transmit information on the tool to be applied in a separate

syntax file in the transmission server 300.

The tool server 400, for managing tools applied to the broadcast

content, systematically manages encrypting/decrypting and/or

scrambling/descrambling and/or watermarking/fingerprinting tools for the

broadcast content. The tool server 400 can include a server for registering the

tool, and a server of tool management authority for distributing/managing the

tool. The tool server 400 is for downloading the tools stored in a smart card of

this embodiment.

The clearing house 300-2, a kind of a server system, takes charge of a

function of issuing a license including authority and conditions for controlling

use and distribution of broadcast content, a function of

billing/payment/settlement based on content use, and a function of

user/device/content/domain authentication. The clearing house 300-2 may be

an integral authentication system of a broadcasting standard authority for

integrally providing digital broadcasting, or may be an authentication system

separately provided at each broadcasting station. The clearing house 300-2

registers the smart card, and issues at least one of the necessary security key,

key information, and certificate.

The producer server, the clearing house 300-2, the transmission server

300-1, and the tool server 400 belong to a broadcasting server domain that is a

collection of authorities forming a broadcasting station, from a user's

standpoint. From the standpoint of the content execution device 100

according to this embodiment, the transmission server 300-1 and the clearing

house 300-2 of the broadcasting server domain, which are remotely connected

to the content execution device 100, are collectively called a broadcasting

station server 300, and the tool server 400 and the broadcasting station server

300 are collectively called a broadcasting sever.

The content protection/management system to which the present

invention is applied can be used in association with the inventive home

domain system having a plurality of content execution devices and/or a

plurality of users included in one home domain. In this case, content re¬

distribution between devices can be content re-distribution between different

home domains, and conversional re-distribution of the content can be content

re-distribution between the same home domains.

For this, an authentication data storage module of the clearing house

300-2 can have device and/or user information included on a home domain-

by-home domain basis, and an authentication execution module can perform a

registration procedure for the device and/or the user included on a home

domain-by-home domain basis.

In this case, the content execution device of this embodiment can be

used as a home domain controller of the home domain system having the

plurality of content execution devices and/or the plurality of users included in

one home domain. The home domain refers to one home domain controller

and groups of users and devices (SAV, PAV) belonging to the home domain

controller. One home domain controller defines one home domain, and each

home domain includes a plurality of users and devices. It can be embodied

that, like a set-top-box receiving digital broadcasting, the home domain

controller combines one multimedia player by itself, and can also be embodied

to take full charge of only home domain management. As such, the home

domain controller performs an important role in defining each home domain

and managing each user and/or device. The content execution device of this

embodiment is capable of easily and safely performing subscriber

authentication using the smart card and has features suitable to its role as the

home domain controller.

Hereinafter, a preferred embodiment of the present invention will be

described in detail with reference to the accompanying drawings. This

embodiment is provided only for example and not intended to limit the scope

of the present invention.

The content execution device of FIG. 2 is an exemplary embodiment

where an independent authentication module is embodied as the smart card,

and includes an authentication support module 110 for providing a user

authentication channel between the connected smart card 200 and the external

broadcasting station server 300; a tool agent 120 for calling the tools stored in

the connected smart card 200; and a content execution unit 130 for executing

content data received from the external broadcasting station server 300.

The authentication smart card 200 connected to the content execution

device 100 of this embodiment is comprised of a smart chip having an

embedded central processing unit (CPU) and a storage memory (EEPROM).

And, in terms of constituent elements of the present invention, the

authentication smart card 200 includes a tool storage unit 210 for storing tools

necessary for playing the content; an authority storage unit 230 for storing

authority information on an external broadcasting server; and an

authentication module 220 for performing mutual authentication for the

external broadcasting server.

The smart card 200 can also be embodied as an RF card employing an

RF wireless communication method, but is preferably embodied using a

contact type card employing a contact pad communication method in order to

secure stable connection with the content execution device 100.

The authentication support module 110 can include a contact type

terminal for contacting the contact type smart card, and a smart card interface

module for converting data to or from a serial communication format for the

smart card.

The content execution unit 130 and the tool agent 120 can be

concretely embodied by an arithmetic unit such as a CPU included in the

content execution device, a program executed by the arithmetic unit, and an

arithmetic memory such as a RAM for loading the program. The content

execution unit 130 has a similar structure and operation as a general

multimedia execution device. However, in the case where a specific tool

stored in the smart card 200 is required to play the content, the content

execution unit 130 can call the tool agent 120. The tool agent 120 serves to

load the tool necessary for executing content data, from the tool storage unit

210 of the smart card 200, and execute the loaded tool.

The content execution device 100 of this embodiment can further

include a broadcast receiving stage 140 for connecting to the external

broadcasting station server 300 using a remote communication channel such as

the Internet, and performing necessary data communication.

The tool storage unit 210 and the authority storage unit 230 can be

embodied by an EEPROM embedded in one chip inside the smart card, and

the authentication module 220 can be embodied by a CPU core embedded in

one chip inside the smart card and a corresponding program. The smart card

can further include a serial communication interface capable of performing

serial data communication with the outside (content execution device in this

embodiment) through a contact pad. The tool storage unit 210 is for storing

tools that are usually distributed only to users permitted by the broadcasting

station. The authority storage unit 230 stores identification information of

users (to be precise, smart card users) who subscribe to the broadcasting

station, and information (e.g. key information, and certificate) necessary for

connection (or authentication). Accordingly, a subscriber registered with the

broadcasting station and having an issued smart card can execute broadcast

content, as long the subscriber has his/her own smart card, according to his/her

subscription authority, in any content execution device (however, smart card

insertion should be possible) without separate management. The

authentication module 220 can hold a security key (a symmetric key method

or an asymmetric key method) corresponding to a security key of the external

broadcasting server, and its own authenticity can be confirmed through mutual

authentication with the broadcasting server. Mutual authentication refers to a

smart card authentication method including authentication of the broadcasting

server by the smart card, using a feature of the smart card having a self-

arithmetic function. Mutual authentication is a technology widely used in the

smart card industry.

Meanwhile, the tool agent 120 is more useful in an embodiment

employing a content playing software package means of a tool pack structure

of FIG. 3.

One example of the tool pack structure is a software and data package,

and is constituted of a tool group including bibliographic information of the

tool pack; a tool agent that is original data before being loaded as the tool

agent of FIG. 2; and tool group possessing at least one tool program activated

by the tool agent and processing content data by a predetermined rule. Each

type of content data providing service such as public broadcasting or Internet

broadcasting has its own separate tool pack. In different embodiments, the

tool pack structure may further include a tool pack signature value for

guaranteeing its tool pack data packet authenticity (indicating that the data

packets were created by an authorized person without forgery or alteration).

The tool pack information can include a tool server URL indicating a position

of the tool server shown in FIG. 1.

It is desirable for the tool agent make public its specifications such as a

call interface and/or a parameter and a return variable, for the convenience of

manufacturers of external devices or application programs handling content

data encoded by the tool pack. It is desirable that, when the tool pack agent

intends to execute the content data needing the tool pack, the content data is

previously loaded into the tool agent.

The tool program is for a separate encoding/decoding process. While

processing a task that has to be performed, the activated tool agent can call

one or more tool programs and authorize the called tool programs to perform

the necessary encoding/decoding process. However, it is desirable that, since

the tool agent is called by the external device or the application program

handling the encoded content data, related manufacturers recognize

specifications such as the call interface and/or the parameter, and the return

variable for the tool agent. But, since the tool program is called only by the

tool agent, in the case where a specification such as a call interface and/or a

parameter as well as a return variable for the tool program are protected in

private, security of content data conversion can be strengthened without

inconveniencing manufacturers of external devices and application programs.

Meanwhile, the plurality of tool programs included in the tool pack

may include all private tool programs and all public tool programs used by the

tool agent, or may not include a part of the public tool programs. When most

frequently used public tool programs in the plurality of tool packs are

separately stored, tool pack data storage efficiency can be improved, though

the latter alternative provides somewhat weaker security than the former. For

this purpose, the latter alternative should include a common tool pack structure

that is a collection of one or more tool programs whose execution

specifications, such as the call interface and/or the parameter, and the return

variable, are open to the public.

Operation of a broadcasting service providing system according to this

embodiment will be described with respect to several detailed scenarios.

Scenario I. Subscription to new broadcasting service

This scenario is as follows. Broadcasters "A" and "B" use their own

protection tools to protect their paid channel services. The respective

broadcasters transmit their tool information and tool initialization information

together with content. The broadcasters "A" and "B" transmit their protection

tools to a tool server of a tool registration authority (TRA). The tool server

registers, manages, and transmits a new tool to an end user (device). A user

"C" receives the paid channel service from the current broadcaster "A".

Further, the user "C" desires to subscribe to a new paid channel service from

the broadcaster "B".

As shown in FIG. 4, a method for subscribing to a new broadcaster's

content providing service applied in this scenario includes the steps of, in the

user device 100, requesting the new subscription from a broadcasting station

server 300 of the new broadcaster (Sl 10) and transmitting user information to

the broadcasting station server 300 (S 124); in the broadcasting station server

300, confirming the received user information (S 126), and registering the

user's smart card 200 (S 132, S 134); in the broadcasting station server 300,

generating key information (S 136) and transmitting the generated key

information to the smart card 200 (S 140); and in the smart card 200, storing

the key information in its internal memory (S 150).

The structure shown is embodied using the key information as a

certificate stored in the smart card. The key information is used for generating

a descrambling key in the smart card 200. In different embodiments, the

structure may be more complex, and may use a certificate having a format

defined in a separate public authentication authority.

Through the above procedure, the user "C" completes subscription to

the new broadcasting service "B". A subscription certificate of the

broadcasting service "A" and a subscription certificate of the broadcasting

service "B" are stored in the smart card of the user "C" thereby completing the

subscription. As such, if the user "C" completing the subscription connects

the smart card having the embedded subscription certificate to any device (e.g.

set- top-box), he/she can receive broadcast content from a broadcasting server

of the broadcaster "B".

However, when the broadcasting server of the broadcaster "B"

processes (encodes) and provides content data using its own tools, the user

"C" device receiving the content data requires tools for inversely processing

(decoding) the received content data. In a subscription-completed state, the

user "C" does not have the tools for the content data received form the

broadcaster "B". As shown in FIG. 5, a method for acquiring the tools of the

broadcaster "B" includes steps of, in the user device 100 connected with the

smart card 200, connecting to the tool server 400 and requesting a tool for a

specific broadcast (S 160); in the tool server 400, verifying the smart card 200

(S 170); in the tool server 400, transmitting the tool for the broadcast to the

user device 100 (S 180); and storing the received tool in the smart card 200

(S190).

The broadcasting station server 300 requested to transmit the broadcast

content by the user device 100 transmits the tool information including a tool

version to the user device 100 together with the content. In different

embodiments, the tool information may further include a seed number for

watermark extraction or a key value for decrypting the encrypted content data.

The user device 100 receiving the content data confirms whether or not there

are the tools corresponding to the tool information received together with the

content in its memory or smart card 200. If there are not suitable tools, the

above tool downloading process is performed, and if there are the suitable

tools, the content is executed (played) using the suitable tool.

Scenario II. Upgrading of protection tool

This scenario is as follows. A broadcasting station "A" uses its own

protection tool to protect its paid channel service. The broadcasting station

"A" has decided to employ a new tool to protect its new service or upgrade a

given tool. At present, a user "C" receives the paid channel service from the

broadcasting station "A". A content execution device (including smart card)

of the user "C" has only an earlier version protection tool and therefore is

required to replace it with the new version tool in order to continuously

receive the service of the broadcasting station "A" in the future. In a

broadcasting station server of the broadcasting station "A", the upgrade -

decided (or newly employed) tool is registered with the tool server and, when

broadcast content is provided, the tool information including a tool version

value is transmitted together with the content.

Methods for the user device to store the upgraded tool in its smart card

include a method of connecting to the tool server and receiving the tool, a

method of receiving the tool from the broadcasting station server, and a

method of connecting to a place indicated by a tool link received together with

the broadcast content, and receiving the tool. In all the above three cases

where the user device connects to a broadcasting station server positioned at a

remote place and downloads the tool, operations performed are almost the

same. Therefore, only downloading from the tool server will be described in

detail below. Alternatively, the tool or the tool link can be broadcast together

with the content.

If the broadcasting station "A" decides to employ the new tool for its

own permanent broadcasting service, first, it registers the new tool with the

tool server. After that, processes of FIG. 6 are performed. The broadcasting

station "A" broadcasts the new tool and related information together with the

broadcast content for the logged-in (S210) user device 100 (S220). The user

device 100 with the smart card 200 receiving the content performs a tool

transmission request procedure. The tool transmission request procedure

includes steps of determining a tool necessary for executing the received

content (S230); determining whether or not the necessary tool is in the smart

card 200 (S240); and connecting to the tool server 400 and requesting a tool

not in the smart card 200 (S260).

The tool server 400 receiving the tool transmission request performs a

procedure of tool transmission. The tool transmission procedure includes

steps of verifying the smart card 200 (S270); and transmitting the tool for the

broadcast content to the user device 100 (S280). After that, the user device

100 stores the received tool in the smart card 200 (S290), and executes the

content using the newly introduced tool.

Scenario III. Transmission of broadcast content to another STB

This scenario is as follows. A broadcasting station "A" allows the end

users to transmit specific content (all or some) to another device (set-top-box)

of a different domain. The broadcasting station "A" and a broadcasting station

"B" use their own protection tools for content protection. It is assumed that

the broadcasting stations "A" and "B" register their own protection tools with

the tool server. A user "C" subscribes to the broadcasting station "A" and a

user "D" subscribes to the broadcasting station "B". The user "C" desires to

distribute the content of the broadcasting station "A" from his/her device

(source device) to a device (target device) of a user "D". This scenario is

different from a scenario described later in that content distribution is

performed from a device registered as being of the user "C" to a device

registered as being of the other user "D".

As shown in FIG. 7, a re-distribution method of the content stored in

the source device of the user "C", which applies to this scenario, includes

steps of checking whether or not the content intended to be re-distributed are

permitted for re-distribution (S310); transmitting the content, use tool

information, and a pointer of the broadcasting station to the target device

(S320); in the target device, requesting the broadcasting station server for

permission to execute the received content (S330); and receiving the execution

permission (S335) and playing the content (S340).

The re-distribution permission checking step (S310) is performed such

that a controller of the source device 100-1 checks the bibliographic

information of the content data stored in an internal storage memory and

confirms whether or not it indicates that the content is re-distributable. In

order to prevent unlawful damage to the indication regarding permission, the

bibliographic information is preferably encrypted. However, in the case where

there is a procedure (e.g. S330 and S335 below) of checking with the

broadcasting station whether or not re-distribution is again enabled in a

subsequent process, the bibliographic information may not be encrypted.

In embodiments where re-distribution is more strictly regulated, after

the re-distribution authority checking step (S310), a step of authenticating the

target device 100-2 in the external broadcasting station server 300 may be

further included. This is to realize a policy of permitting content re-

distribution at least between users subscribing to the content broadcasting

service of the present invention (that is, users subscribing to any one

broadcasting station service). In order to more suitably apply this step, the

content execution devices used in the broadcasting system of the present

invention preferably have inherent identification values such as a media access

code (MAC). In this embodiment, the content execution device can be

identified using the inherent identification value (for example, a MAC value or

an identification number allotted with application) of the smart card inserted

into each content execution device. It is not desirable for the inherent

identification values to be allotted to all of the content execution devices,

because of a problem of compatibility with a conventional device and increase

of a device manufacturing cost. It is desirable for the inherent identification

values to be allotted to the smart cards so that devices are identified using the

smart cards, because this makes application easy, cheap and convenient for

users as well.

It is possible for the tool server of a tool registration/management

center, not of the broadcasting station server 300, to perform user confirmation.

Such an embodiment may be desirable because it easily allows the tool server

to have information on all subscribers of all broadcasts provided according to

the content broadcasting service according to the present invention.

The authenticating step of the target device 100-2 can include the steps

of, in the source device 100-1, transmitting the identification value of the

target device 100-2 to the tool server; in the tool server, searching a DB for the

received identification value and determining whether or not the device

corresponding to the identification value holds re-distribution authority; and

transmitting the determination result to the target device 100- 1.

In the step of transmitting the content/related information (S320), the

related information transmitted from the source device to the target device can

be information on the tool used for playing the transmission content, and a

pointer (URL, link) of the broadcasting station having rights to the content

intended to be transmitted. In the case where the related information is

transmitted to a user who does not subscribe to a broadcasting copyright

management system, it may be transmitted together with a pointer of the tool

server.

In different embodiments, after the step of transmitting the content and

related information (S320), a step of, in the target device 100-2, acquiring a

needed tool from the tool server (not shown) may be further included. The

tool acquiring step is omitted in cases where the target device 100-2 already

has the tool, and where the necessary tool is transmitted together in the

transmitting step of the content/related information. The target device 100-2

requests the tool server to transmit the necessary tool and downloads the

necessary tool. In different embodiments, the requested tool server may

transmit the tool to the target device 100-2 with a limit on the number of times

the tool can be used.

The step of requesting content execution permission (S330) is

performed such that the target device 100-2 requests the broadcasting station

server 300 of the broadcasting station holding rights to the content for

permission to execute the re-distributed content, through wired/wireless

communication means. The broadcasting server 300 decides whether or not to

issue permission from its own DB in consideration of information on a number

of times the content has been re-distributed and a re-distribution limit and,

upon decision to grant permission, prepares and transmits the permission with

a specified range to the target device 100-2 (S335).

In the step of playing the content (S340), the target device 100-2 plays

the re-distributed content using the received permission. The permission may

be a software module having an electronic file format and may be

unconditionally required for execution of the re-distributed content.

In another embodiment of a method of re-distributing content to

another user's device (target device) with a structure of FIG. 8, the method of

re-distributing content stored in a user "C" device (source device), applied to

the scenario, includes steps of checking whether or not the content intended to

be re-distributed are permitted for re-distribution (S410); receiving

authentication of the target device 100-2 from the external tool server 400

(S420); transmitting the content, use tool information and play permission

information to the target device 100-2 (S430); and playing the content in the

target device 100-2 (S440).

The step of checking re-distribution permission (S410) can be

performed such that a controller of the source device 100-1 checks the

bibliographic information of the content data stored in an internal storage

memory, and confirms whether or not it indicates that the content is re¬

distributable. In order to prevent unlawful damage to the indication regarding

permission, the bibliographic information is preferably encrypted. However,

in the case where there is a separate procedure of checking with the

broadcasting station whether or not re-distribution is again possible in a

subsequent process, the bibliographic information may not be encrypted.

The step of receiving authentication of the target device (S420) is

included to realize a policy of permitting content re-distribution at least

between users (that is, users subscribing to any one broadcasting station

service) of the content broadcasting service of the present invention. In order

to more suitably apply this step, the content execution devices used in the

broadcasting system of the present invention preferably have inherent

identification values such as a media access code (MAC). In this embodiment,

the content execution device can be identified using the inherent identification

value (for example, a MAC value or an identification number allotted with

chip application) of the smart card inserted into each content execution device.

It is not desirable for the inherent identification values to be allotted to all of

the content execution devices, because of a problem of compatibility with a

conventional device and increase of a device manufacturing cost. It is

desirable for the inherent identification values to be allotted to the smart cards

so that devices are identified using the smart cards, because this makes

application easy, cheap and convenient for users as well.

The step of receiving authentication of the target device (S420) can

include steps of in the source device 100-1, transmitting the identification

value of the target device 100-2 to the tool server 400 and requesting

authentication (S422); authenticating the target device 100-2 (S424); and

transmitting the determination result to the source device 100- 1.

In some embodiments, in the authenticating step (S424), the

identification value of the target device may be searched for within the DB to

perform offline authentication for determining whether or not the device

having the identification value holds the authority for re-distribution, or

connection with the broadcasting server (not shown) may be made to directly

perform online authentication.

In the step of transmitting the content/related information (S430), some

of the related information transmitted from the source device 100-1 to the

target device 100-2 is information on the tool used for playing the

transmission content. In some embodiments, the target device 100-2 may

check whether or not it has the tool corresponding to the tool information, and

if it doesn't, it may notify the source device 100-1 and receive the tool from

the source device 100-1.

In the content playing step (S440), the target device 100-2 plays the

received content using the necessary tool. Also in this step, in some

embodiments, the target device 100-2 may play the re-distributed content

using the received permission.

Scenario IV. Transmission of broadcast content to other multimedia

devices

This scenario is as follows. A broadcasting station "A" allows a user

to play specific content (all or some) in its own portable device. The

broadcasting station registers a tool for playing the portable-device with the

tool server. The portable device generally has low performance in playing the

broadcast content. Accordingly, the content requires conversion to a suitable

resolution depending on specifications of the portable device. This constitutes

conversion of content of literary work. A user "C" stores the broadcast

content in the source device, and intends to play it in its own portable device

(target device).

As shown in FIG. 9, a method of re-distributing the content stored in

the device of the user "C", applied to this scenario, includes steps of: checking

whether or not the content stored in the source device 100-1 are permitted for

conversional re-distribution (S510); requesting the external tool server 400 to

transmit a tool for the portable device (hereinafter, referred to as "portable

tool"), and downloading the portable device tool (S520); requesting the

broadcasting station server 300 for permission to perform altered

retransmission to the target device 100-3, and receiving the permission (S530);

transmitting the content, the portable tool, and the retransmission permission

to the target device (S540); and in the target device (100-3), playing the

content using the portable tool and the re-transmission permission (S550).

The step of checking for conversional re-distribution permission

(S510) can be performed such that a controller of the source device 100-1

checks the bibliographic information of the content data stored in an internal

storage memory and confirms whether or not it indicates that the content is

alter-and-re-distributable. In order to prevent unlawful damage to the

indication regarding permission, the bibliographic information is preferably

encrypted.

After the step of checking for conversional re-distribution permission

(S510), a step of confirming whether or not the target device 100-3 is a

member of the same domain to which the source device 100-1 belongs can be

further included. The purpose of this step is to apply a policy for permitting

conversional re-distribution of content only between devices of the same user

or devices belonging to any one of the service domains (e.g. a home domain).

Here, in some embodiments, a list of devices (including portable devices)

having the relationship may be registered with the broadcasting station server

300 or the tool server 400, and even with a user's main device (identified by

the smart card and serving primarily to receive content from the broadcasting

station server).

The step of downloading the portable tool (S520) is performed in the

source device 100-1. This is because the source device 100-1 is easy to

connect to the tool server 400 by means such as the Internet, whereas the

target device 100-3 is mostly used in an offline state.

The step of requesting and receiving conversional re-distribution

permission (S530) can include steps of, in the broadcasting server 300,

searching the DB for the re-distribution policy and the user authority for the

content, and determining whether or not portable transmission is permitted;

upon decision regarding portable transmission permission, preparing portable

transmission permission; and transmitting the prepared permission to the

source device 100-1.

In the content transmission step (S540), the source device 100-1

transmits the content, the portable tool, and the portable permission to the

target device 100-3 through a wired/wireless communication means (generally,

a cable). When the same tool as the received portable tool is already stored in

the internal storage memory, the target device 100-3 may receive only the

content and the portable permission.

In the content playing step, the target device 100-3 executes the

received content using the portable tool and the portable permission.

In some embodiments, the initially provided content in the source

device 100-1 may be converted into portable content in the broadcasting

station server or the target device 100-3. If the content is converted in the

source device 100-1, less communication is required. In this case, the content

transmitted from the source device 100-1 to the target device 100-3 is portable

converted (that is, downsized) content data and the source device receives a

downsizing tool from the broadcasting station server 300 or the tool server 400

and converts the content.

While the invention has been shown and described with reference to

certain exemplary embodiments thereof, it will be understood by those skilled

in the art that various changes in form and details may be made therein

without departing from the spirit and scope of the invention as defined by the

appended claims.