KR100443412B1 - An illegal digital contents copy protection method using hidden agent - Google Patents

Abstract

It is a way to protect contents against illegal behaviors such as illegal copying that can occur in the distribution process and provide convenience to the user. Therefore, it is concealed to prevent illegal copying and illegal use of contents. Use an agent (Hidden Agent). This hidden agent is embedded in the contents without special installation so that the illegal copy can be blocked by verifying illegal copy and illegal use. It can also take the role of watermarking because it is hidden from users.

Description

{An illegal digital contents copy protection method using hidden agent}

The present invention relates to a method for copy protection of digital content using a hidden agent, and more particularly, it is not using a smart card or a dedicated browser required for providing existing content. With Hidden Agent, only the correct user can check the Hidden Agent for illegal copy and illegal use that can be caused by using the Agent hidden inside. It relates to a method for preventing piracy.

The use of global distribution systems such as the Internet for the distribution of digital assets such as music, movies, computer programs, images, games and other content continues to increase. At the same time, owners and presenters of valuable digital content have been passive in using the Internet for the distribution of digital assets for a variety of reasons.

One reason is that the owner fears unauthorized copying or plagiarism of digital content. Electronic delivery of digital content removes several barriers to plagiarism. One barrier removed by electronic distribution is the need for tangible recordable media itself (eg, diskette or CD-ROM). Copying digital content to tangible media is costly, in many cases even at a small cost for blank tapes or recordable CDs. However, for electronic distribution, tangible media is no longer needed. The cost of tangible media is not considered because the content is distributed electronically.

The second barrier is the content stored in the format of the content itself, that is, in analog format to the digital format. In the case of content stored in analog format, such as a printed image, for example, the copy is of lower quality than the original when played back by photocopy. Each time you make a copy, often called generation, you're inferior to the original. This degradation no longer exists when the image is stored digitally. Each copy and every copy of the copy is as crisp and fresh as the original. The overall effect of a complete digital copy combined at very low cost for distributing content electronically and for distributing content widely over the Internet is relatively plagiarized to facilitate distribution of unauthorized copies. With several keystrokes, plagiarism can transmit hundreds or even thousands of copies of digital content over the Internet. Thus, there is a need to ensure the protection and security of digitally distributed digital assets.

Providers of digital content want to establish a secure global distribution system for digital content that protects the rights of the content owner. Problems in establishing a digital content distribution system include developing a system for electronic distribution of digital content, rights management and asset protection. Digital content distributed electronically includes content such as print media, movies, games, programs, television, multimedia, and music.

Digital Rights Management (DRM) must meet the following six conditions for electronic content. This condition is essential for electronic rights management and is a condition for the whole series of actions such as the management, distribution, and charging of contents.

① The user must be able to authenticate whether the user is legitimate or not.

② The user should be able to copy and distribute to the authorized user of the contents, and the provider should have the right to copy and distribute.

③ If you are not a legitimate user of the content, illegal duplication of the content should be prevented.

④ There should be a distinction between copyright, ownership, and usage rights for content, so there is a distinction between copyright, ownership, and use.

⑤ Charges must be made for legitimate users who use the content.

⑥ It should be possible to provide content only to legitimate users through access control for anonymous users.

Electronic rights management can be divided into two types according to the content providing method. In order to receive the content, the content itself is played through a dedicated browser, and the user's key is also stored in the dedicated browser, and the user's information is stored and used in a smart card. There is a method using a smart card.

The process will be described in more detail with reference to the flowcharts of FIGS. 1 and 2. In the case of Figure 1 will be described in a manner for a dedicated browser. After the content is provided, the playback is played through a dedicated browser. The user makes a content request (S11), and selects and transmits a payment method for the content along with a message described about the user's content and authority (S12).

The user transmits the purchase information and the key for encrypting the content to the seller (S13). The seller then sends a dedicated browser, a tool for playing the content, before the content is provided. The received encrypted key is encrypted and transmitted using the received key (S15). The received encrypted content is played through the user's dedicated browser. After the authentication process, it is reproduced. (S16)

This method is provided by using a dedicated browser, so that the key belongs to the dedicated browser for the user, so the risk of loss of the key is small, and the record of the use of the content is recorded on the dedicated browser. The record shows that illegal use can be identified. However, this method is applicable to only one of wired and wireless methods, so a dedicated browser that can be applied to wired and wireless devices must be developed. In addition, if an illegal user acquires a bundle of contents, if a user's key is exposed, there is a possibility of illegal copying. It is shown.

Another method will be described in more detail with reference to the flowchart of FIG. 2. Keys according to content playback are stored in a smart card, and contents are played back through these keys. The user requests the content (S21), and selects and transmits a payment method for the content together with a message described about the content and the authority of the user (S22).

The user transmits a key for encrypting the purchase information and the content to the seller (S23). The key used for this is selected from the smart card and transmitted to the seller. (S24) The seller uses a key received from the user. The content is encrypted and transmitted. (S25) The received content is played through the user's browser. At this time, the authentication is performed after the authentication process is performed through the key of the smart card as to whether the content is a valid user or an illegal user. (S26)

The following method is provided by using a smart card, so that the key belongs to a smart card for the user, so it can be applied to wired and wireless environments through a card reader. The advantage is that it can be combined with a dedicated browser. However, as the risk of losing smart cards increases, the risk of losing keys used for contents also increases. If you try to restrict illegal behaviors other than Smart Card, it can be done through incorporation with other technologies, but it may be less convenient for users.

As described above, the conventional method of using a dedicated browser or a method of using a smart card is used in a wired and wireless environment by using a specific object (dedicated browser, smart card) specific to the user in providing contents. There is a problem that it is difficult to apply, and can be distributed using the content provided by the seller to the user.

The present invention aims to prevent illegal copying of digital content.

Another object of the present invention is to provide a data processing method capable of maintaining the confidentiality and safety of digital content.

Still another object of the present invention is to provide a method for extracting information on illegal use when illegal users make illegal use of contents.

Digital content copy protection method using a hidden agent according to the present invention for achieving these objects comprises the first step of receiving information and payment information of the content from the user computer; Extracting content information and payment information from the received information to generate illegal copy protection information; Receiving a secret information of a user necessary for generating an encryption key from a user computer; A fourth step of generating a secret key from the secret information extracted from the received secret information by using a secret value of the server, performing a digital signature on the value, and transmitting the secret key to the user computer; A fifth step of receiving verification information of the user on the secret key value of the server extracted by using the digitally signed information provided from the server through the fourth step; A sixth step of transmitting, to the intermediate server, the private key value verified through the fifth step and the illegal copy protection information generated in the second step; A seventh process of encrypting the content and the anti-piracy information with the secret key value verified in the fifth process using the illegal copy protection information of the second process with respect to the content requested by the user in the first process; and; An eighth step of transmitting an illegal copy prevention information to an intermediate server when a copy or move command on an operating system is recognized by an agent provided by concealing the content to prevent illegal copying of the content; A ninth process of verifying the duplication authority by comparing the information extracted from the intermediate server, which has been received and transmitted by the concealment agent in the user computer, transmitted from the intermediate server with the information provided from the server through the sixth process; ; And a tenth step of transmitting the verification result according to the ninth step from the intermediate server to the user computer.

Detailed features of the hidden agent (Hidden Agent) to prevent illegal copy according to the present invention is the use of illegal copy protection information between the hidden agent (Hidden Agent) and the intermediate server at the time of the generation of illegal copy protection information and illegal copying.

1 is a flowchart illustrating a copy protection method of a dedicated browser according to the prior art;

2 is a flowchart illustrating a copy protection method using a smart card according to the prior art;

3 is a flow chart showing the progress of the anti-piracy method using a hidden agent according to the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. First, the requirements of the anti-piracy hidden agent method that can be implemented by the present invention will be described.

First, the requirements for the anti-piracy model

① Confidentiality: In providing contents, the seller should transmit the contents to the user in a safe and accurate manner from the eavesdropping of the third party.

② Authentication: The Hidden Agent method is used to guarantee that the origin of content is transmitted and received and that it is not forged or altered by an illegal third party during transmission.

③ Rejection blockade: Content should be denied between the parties using / receiving whether or not the content has been sent or received.

Second, hidden agent requirements

① Uniqueness: The Hidden Agent provided to the user must be unique and cannot be deleted by the user. When deleting a hidden agent, the content itself must be deleted.

② Active: The hidden agent should be loaded at the same time as storing the content on the user's computer.

③ Confidentiality: In order to prevent illegal copying, a provider must be provided and a hidden agent must have a generation factor that can be created.

3 is a flowchart illustrating a procedure of a hidden agent method for preventing illegal copying according to the present invention. Process of generating anti-piracy information and secret key agreement (A1 ~ A4) between user and seller to receive contents largely, and providing content including anti-piracy information in hidden agent based on generated secret key ( B1 to B3), and the replication authority approval verification process (C1 to C3) performed by the intermediate server at the time of replication attempt.

In the present invention, a time-stamp is generated and used by a seller to prevent illegal copying from being attempted. In addition, the secret key information is not shared in advance, but when a content request is made, a secret key is generated by sharing secret information between the seller and the user. In the case of a hidden agent, the seller generates from the illegal copy information of the user. The hidden agent is unique for each content and the same hidden agent is not generated, thereby protecting the content from the user's fraud. This prevents user fraud prior to piracy prevention.

Symbols displayed in the present invention are defined as follows.

U: User

MS: CP Master Server

FS: CP Front-Middle Server

ID: User's ID

L: Hash value: L = H (ID∥D)

KA: Encryption key used by the hidden agent

T: time-stamp

Sig _user : User's signature value

Sig _MS : Signature value of CP Master Server

A: hidden agent

D: Type of permission (copy count permission, usage count permission, etc.)

P: Prime number published by the user

G: Primitive root of GF (P) published by the user

Y _* , X _* : Public and private keys of * based on DH key exchange algorithm

K: encryption key for content provision

S: Contents Class

M: Payment Value

R: Hidden Agent Value

C: Contents provided

First, the process of generating anti-piracy information and secret key agreement between a user and a seller to receive content will be described in detail.

The user sends the type (S) for the desired content and the payment price (M) for the payment to the CP Master server. (A1)

Using the information received from the user, the seller generates anti-piracy information (D, L).

D = S + M, L = H (ID ∥ D). … … … … … … … … … … … … … (A2)

It must be for exchanging a key that can encrypt the content in order to receive the content. The user calculates the next Y _A using the secret value (X _user ), and then transmits the ID and Y _A values of the user.

(U): Y _A ≡ g ^Xuser mod p

(U)-> (MS): Y _A sig _user (ID Y _A )…. … … … … … … … … … … (A3)

The merchant server calculates the secret key K using the secret value X _MS of the server using Y _A received from the user. Merchant server calculates Y _B using secret value (X _MS ) and sends Y _B , S, M to user.

(MS): K ≡ (g ^Xuser ) ^XMS (mod p) ≡ Y _A ^XMS (mod p) ≡ Y _B ^Xuser (mod P)

(MS): Y _B ≡ g ^XMS mod p

(MS)-> (U): Y _B sig _MS (Y _B S) M…. … … … … … … … (A4)

Next, based on the generated secret key, we will look at the details of the content providing step including the anti-piracy information in the hidden agent (Hidden Agent).

The user calculates the secret key value K using the Y _B received from the seller server and sends a key exchange end message.

(U): K ≡ (g ^XMS ) ^Xuser (mod p) ≡ Y _B ^Xuser (mod p) ≡ Y _A ^XMS (mod P)

(U)-> (MS): end message… … … … … … … … … … … … … … (B1)

The arguments generated by the seller server are sent to the intermediate server.

(MS)-> (FS): (ID, L, D, M, S, T)... … … … … … … … … … … … (B2)

The seller server inserts a hidden agent suitable for the user and transmits the content. At this time, the point in time confirmation value T has a point in time to be copied. A hidden agent and a time confirmation value T are included in the content and transmitted.

(MS)-> (U): E _K (C _(A∥T) ). … … … … … … … … … … … … … … … (B3)

Next, we will take a closer look at the replication authorization approval step performed by the intermediate server when the user wants to copy or illegal copies of the contents.

When the user executes commands such as COPY and MOVE on the operating system, the hidden agent operates. The ID, S, M, and L are encrypted using the key received from the server and transmitted to the intermediate server.

At this time, the time point check value T in the hidden agent means the initial time point check value T. The intermediate server also works with the Hidden Agent. If the hidden agent cannot connect to the server, the copy right is not granted.

When the COPY command is executed on the user's computer, a hidden agent is automatically performed (C1), and S, M, and T (internal factors of the hidden agent) are encrypted and transmitted to the intermediate server.

(U)-> (FS): E _KA (ID, S, M, L, T)…. … … … … … … … … … (C2)

The intermediate server calculates D and L using the IDs, S, and M received and compares them with the contents of its own database and grants copy rights. Compare the hidden agent (Hidden Agent) and the time check value (T) in the intermediate server to check whether illegal copying has been made.

(FS): D = S + M

L = H (ID ∥ D)

T = T '?, D = D'?, L = L '? … … … … … … … … (C3)

The intermediate server compares and sends a replication permission acknowledgment message about the correct replication.

(FS)-> (U): E _KA (ID ∥ Yes or No)…. … … … … … … … … … … … … … (C4)

The technical spirit of the present invention has been described above with reference to the accompanying drawings. However, the present invention has been described by way of example only, and is not intended to limit the present invention. In addition, it is obvious that any person skilled in the art may make various modifications and imitations without departing from the scope of the technical idea of the present invention.

As described above, the present invention solves a decrease in user convenience due to a dedicated browser or a smart card in a conventional method of providing content, and sufficiently covers elements for preventing loss or illegal copy using a hidden agent. In addition, with the development of computer networks and mobile communications, the information society will provide a variety of content application services, including electronic commerce services. The proposal of the hidden agent method that provides illegal copy protection in such a content service environment will have a great effect in contributing to the development of electronic commerce service and content application services.

Claims (1)

In the digital content copy protection method performed to prevent illegal copying of digital content of a client system (called a "user") in a service providing server (called a "server") that provides digital content through the Internet: A first step of receiving content information and payment information from a user computer; Extracting content information and payment information from the received information to generate illegal copy protection information; Receiving a secret information of a user necessary for generating an encryption key from a user computer; A fourth step of generating a secret key from the secret information extracted from the received secret information by using a secret value of the server, performing a digital signature on the value, and transmitting the secret key to the user computer; A fifth step of receiving verification information of the user with respect to the secret key value of the server extracted by using the electronic signature information provided from the server through the fourth step; A sixth process of transmitting a secret key value verified through the fifth process and illegal copy protection information generated in a second process to an intermediate server; A seventh process of encrypting the content and the anti-piracy information with the secret key value verified in the fifth process using the illegal copy protection information of the second process for the content requested by the user in the first process; and; An eighth step of transmitting an illegal copy prevention information to an intermediate server when a copy or move command on an operating system is recognized by an agent provided by concealing the content to prevent illegal copying of the content; A ninth process of verifying the duplication authority by comparing the information extracted from the intermediate server, which has been received and transmitted by the concealment agent in the user computer, transmitted from the intermediate server with the information provided from the server through the sixth process; ; And copying the verification result according to the ninth step from the intermediate server to the user computer.