WO2007123373A1

WO2007123373A1 - Apparatus and method for transforming drm algorithm of streaming data

Info

Publication number: WO2007123373A1
Application number: PCT/KR2007/002024
Authority: WO
Inventors: Jun-Il Kim; Do-Won Nam; Jung-Soo Lee; Yeon-Jeong Jeong; Jee-Hyun Park; Jung-Hyun Kim; Ki-Song Yoon
Original assignee: Electronics And Telecommunications Research Institute
Priority date: 2006-04-25
Filing date: 2007-04-25
Publication date: 2007-11-01
Also published as: KR20070105273A

Abstract

Provided is an apparatus and method for changing the Digital Rights Management (DRM) algorithm applied to streaming data when the DRM algorithm needs to be changed. The apparatus for changing a first DRM algorithm applied to streaming data into a second DRM algorithm, including: N levels of parsing means for parsing the streaming data; N levels of packetizing means for generating the streaming data by packetizing the data parsed by the N levels of parsing means; a decrypting means connected to an nth level of a parsing means among the N levels of the parsing means and decrypting data parsed by the nth level of the parsing means according to the first DRM algorithm, where n is an integer smaller than N; an encrypting means connected to an mth level of a packetizing means among the N levels of the packetizing means and encrypting data decrypted by the decrypting means according to the second DRM algorithm; and a path managing means for managing a path based on the n value and the m value in order to parse and packetize the streaming data with a minimum number of parsing and packetizing means.

Description

APPARATUS AND METHOD FOR TRANSFORMING DRM ALGORITHM OF

STREAMING DATA

DESCRIPTION

TECHNICAL FIELD

[0001] The present invention relates to an apparatus and method for changing a Digital Rights Management (DRM) algorithm; and, more particularly, to an apparatus and method for changing a DRM algorithm applied to streaming data to the other DRM algorithm.

BACKGROUND ART

[0002] Digital Rights Management (DRM) is a technology for safely distributing digital contents through networks and protecting the digital contents from being unlawfully- copied or unauthorized used.

[0003] For example, if a contents provider provides data including contents encrypted by a first DRM algorithm DRMl and a user has a terminal supporting only a second DRM algorithm. DRM2, then it is required to change the first DRM algorithm DRMl applied to corresponding contents into the second DRM algorithm DRM2 while the corresponding contents are distributed through a network, for example, while the corresponding contents are downloaded or while the corresponding contents are provided through streaming.

[0004] Fig. 1 is a block diagram illustrating an apparatus for changing a DRM algorithm for downloaded data in accordance with the related art.

[0005] As shown in Fig. 1, a conventional apparatus for changing a DRM algorithm for downloaded data includes a DRMl decrypter 101 and a DRM2 encrypter 103. [0006] The DRMl decrypter 101 transforms data Cl encrypted by a first DRM algorithm DRMl to original data Co.

[0007] The DRM2 encrypter 103 transforms the original data Co to encrypted data C2 by encrypting the original data Co from the DRMl decrypter 101 using a second DRM algorithm DRM2.

[0008] As described above, it is comparatively easy to change a DRM algorithm applied to the downloaded data into another DRM algorithm, for example, the first DRM algorithm DRMl to the second DRM algorithm DRM2 , because the output of the decrypter 101 can be used as the input of the encrypter 103 as shown in Fig. 1.

[0009] Unlike the downloaded data, it is not easy to change a DRM algorithm applied to streaming data. The streaming data is generated through a plurality of packetizing steps, and restored into original data through a plurality of parsing steps.

[0010] In case of MPEG-2 data, original data such as video signal and audio signal is transformed to an MPEG-2 elementary stream (ES) by packetizing the original data at the first step. Then, the MPEG-2 ES is transformed to a packetized element stream (PES) by packetizing the MPEG-2 ES at the second step, and the PES is transformed to MPEG-2 transport stream (TS) by packetizing the PES at the third step. Finally, the MPEG-2 TS is transformed to network packet data such as a User Datagram Protocol

(UDP) packet or a Real-Time Transport Protocol (RTP) packet by packetizing the MPEG-2 TS at the fourth step.

The network packet data is transformed to the original data by parsing the network packet data such as a UDP packet or an RTP packet in the reverse order thereof.

[0011] According to a DRM algorithm applied to the streaming data, the intermediate data such as ES, PES, and TS is encrypted or decrypted during a plurality of the packetizing and parsing steps. [0012] However, it is difficult to change a DRM algorithm applied to the streaming data because the intermediate data changes during the parsing or packetizing steps, where the intermediate data is an object to encrypt and decrypt according to a corresponding DRM algorithm. That is, unlike the downloaded data, the output of the decrypter using the first DRM algorithm DRMl cannot be used as the input of the encrypter using the second DRM algorithm DRM2. [0013] Similarly to the conventional technology of changing a DRM algorithm of the downloaded data, a DRM algorithm of streaming data can change by performing all of packetizing steps and a DRM2 encryption step again after the streaming data is transformed to original data by performing all parsing steps and a DRMl decryption step.

[0014] However, it is ineffective to perform all of the packetizing steps again after performing all of the parsing steps on the streaming data to change a DRM algorithm. [0015] Therefore, it is called for to develop a technology for changing a DRM algorithm applied to streaming data, which is distinguished from the conventional technology for changing a DRM algorithm for the downloaded data.

DISCLOSURE TECHNICAL PROBLEM

[0016] An embodiment of the present invention, which is devised to satisfy the aforementioned demand, is directed to providing an apparatus for changing a DRM algorithm applied to streaming data according to needs, and a method thereof.

TECHNICAL SOLUTION [0017] In accordance with an aspect of the present invention, there is provided an apparatus for changing a first Digital Rights Management (DRM) algorithm DRMl applied to streaming data into a second DRM algorithm DRM2, which includes: N levels of parsing means for receiving the streaming data and parsing the received streaming data; N levels of packetizing means for generating the streaming data by packetizing the data parsed by the N levels of parsing means; a decrypting means connected to an n^th level of a parsing means among the N levels of the parsing means and decrypting data parsed by the n^th level of the parsing means according to the first DRM algorithm, where n is an integer smaller than N; an encrypting means connected to an m^th level of a packetizing means among the N levels of the packetizing means and encrypting data decrypted by the decrypting means according to the second DRM algorithm; and a path managing means for managing a path based on the n value and the m value in order to parse and packetize the streaming data with a minimum number of the parsing means and the packetizing means.

ADVANTAGEOUS EFFECTS

[0018] An apparatus and method for changing a DRM algorithm applied to streaming data according to the present invention allows a user to use various streaming services encrypted by different DRM algorithms with diverse DRM client terminals.

[0019] The apparatus and method for changing a DRM algorithm applied to streaming data according to the present invention allows a data provider to provide data regardless of a user' s a DRM system without opening the provider's a DRM system. Therefore, the data provider can have economical benefit and reduce the related cost because it is not required to apply DRM in various formats for data. [0020] The apparatus and method for changing a DRM algorithm applied to streaming data according to the present invention allows a user to use desired data regardless of DRM although a new DRM client is not installed if the user obtains an authority. Since a user is allowed to transfer data to various terminals and use them if the user purchases the authority thereof, the user is not required to purchase new authority although a different DRM client is installed in the other terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Fig. 1 illustrates an apparatus for changing a DRM algorithm applied to downloaded data according to a related art. [0022] Fig. 2 is a block diagram illustrating an apparatus for changing a DRM algorithm applied to streaming data in accordance with an embodiment of the present invention. [0023] Fig. 3 is a block diagram illustrating a DRM transformer shown in Fig. 2.

[0024] Fig. 4 is a block diagram illustrating a DRM transformer for MPEG-2 streaming data.

[0025] Fig. 5 is a diagram illustrating a DRM transformer shown in Fig. 2. [0026] Fig. 6 is a flowchart illustrating a method for changing a DRM algorithm of streaming data in accordance with an embodiment of the present invention.

BEST MODE FOR THE INVENTION [0027] According to an aspect of the present invention, there is provided an apparatus for changing a first Digital Rights Management (DRM) algorithm DRMl applied to streaming data into a second DRM algorithm DRM2 , which includes: N levels of parsing means for receiving the streaming data and parsing the received streaming data; N levels of packetizing means for generating the streaming data by packetizing the data parsed by the N levels of parsing means; a decrypting means connected to an n^th level of a parsing means among the N levels of the parsing means and decrypting data parsed by the n^th level of the parsing means according to the first DRM algorithm, where n is an integer smaller than N; an encrypting means connected to an m^th level of a packetizing means among the N levels of the packetizing means and encrypting data decrypted by the decrypting means according to the second DRM algorithm; and a path managing means for managing a path based on the n value and the m value in order to parse and packetize the streaming data with a minimum number of the parsing means and the packetizing means. [0028] According to an aspect of the present invention, there is provided a method for changing a first DRM algorithm applied to streaming data into a second DRM algorithm, comprising the steps of: receiving the streaming data and parsing the streaming data in N levels; generating the streaming data by packetizing the parsed data through the parsing process in N levels; decrypting the parsed data of an n^th level among the N level parsing steps according to the first DRM algorithm, where n is an integer smaller than N; encrypting data, which is obtained from the decryption process, according to the second DRM algorithm to be packetized in an m^th level packetizing step among the N levels of packetizing steps, where m is an integer smaller than N; and managing a path to parse and packetize the streaming data through a minimum number of parsing steps and packetizing steps based on the n value and the m values.

[0029] The advantages, features and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter. [0030] Fig. 2 is an apparatus for changing a DRM algorithm applied to streaming data in accordance with an embodiment of the present invention.

[0031] As shown in Fig. 2, the DRM changing apparatus of the present embodiment includes a recognizer 201, a parsing and packetizing manager 203, a DRM manager 205, a path manager 207, and a DRM transformer 209. [0032] The recognizer 201 recognizes the format information of streaming data inputted or outputted to/from the DRM changing apparatus, information about a DRM algorithm applied to the streaming data, e.g., a first DRM algorithm DRMl information, and information about another DRM algorithm into which the previous DRM algorithm is changed, i.e., a second DRM algorithm DRM2 information. The streaming format information and the DRM algorithm information can be obtained through various routes. For example, the streaming formation information and the DRM algorithm information can be obtained from a manger or a user directly, from a content provider system or a user terminal through inquiry, or from information such as header information included in the streaming data directly.

[0033] The parsing and packetizing manager 203 stores and manages parsers and packetizers according to various streaming formats, for example, Moving Picture Experts

Group (MPEG) -2 or Internet Streaming Media Alliance

(ISMA). The parsing and packetizing manager 203 also provides a parser or a packetizer corresponding to the streaming format information recognized by the recognizer 201.

[0034] The DRM manager 205 stores and manages a decrypter and an encrypter according to various DRM algorithms, and provides a DRMl decrypter and a DRM2 encrypter according to the DRM algorithm recognized by the recognizer 201. [0035] The DRMl decrypter decrypts the streaming data using a first DRM algorithm DRMl in one of a plurality of parsing steps for parsing streaming data which is encrypted according to the first DRM algorithm and inputted to the DRM transformer 209. The DRM2 encrypter encrypts the streaming data using the second DRM algorithm DRM2 in one of a plurality of packetizing steps for packetizing the decrypted streaming data transferred from a parser using the DRMl decrypter. [0036] For example, in case of the MPEG-2 format, a user datagram protocol (UDP) packet is parsed to a transport stream TS, the TS is parsed to a packetized element streaming PES, the PES is parsed to an elementary stream ES, and the ES is parsed to original data. The DRMl decrypter can decrypt the UDP packet using the first DRM algorithm DRMl, and the DRM2 encrypter can encrypt the PES using the second DRM algorithm DRM2.

[0037] The DRM manager 205 outputs information about a DRMl decrypter and a DRM2 encrypter to the path manager 207. The DRMl decrypter information includes information about the decrypted intermediate data among intermediate data, for example, ES, PES, and TS for MPEG-2, outputted from a plurality of parsing steps. The DRM2 encrypter information includes information about encrypted intermediate data among intermediate data outputted from a plurality of packetizing steps. A DRM encrypting step and a DRM decrypting step interworking with parsing and packetizing steps per a streaming format are decided according to a DRM algorithm. [0038] The path manager 207 generates path information based on the information of the DRMl decrypter and the DRM2 encrypter to change a DRM algorithm applied to streaming data when the streaming data is parsed to intermediate data although the streaming data is not parsed to the original data. The path information denotes information about the type of intermediate data transferred from the parser to the packetizer. [0039] The DRM transformer 209 includes a plurality of parsers for performing a plurality of parsing steps and a plurality of packetizers for performing a plurality of packetizing steps as parsers and packetizers provided from the parsing and packetizing manager 203. Also, a DRMl decrypter and a DRM2 encrypter provided from the DRM manager 205 are connected to some of the parsers and the packetizers . [0040] Since the DRM encrypting step and the DRM decrypting step interworking with parsing and packetizing steps according to a corresponding streaming format are decided according to a DRM algorithm, one of the parsers connected to the DRMl decrypter is decided according to one of intermediate data outputted from a plurality of the parsing steps, which will be decrypted. Similarly, one of the packetizers connected to the DRM2 encrypter is decided according to one of intermediate data outputted from a plurality of the packetizing steps, which will be encrypted.

[0041] The DRM transformer 209 transfers proper intermediate data to be encrypted by the DRM2 encrypter as decrypted intermediate data by the DRMl decrypter from a corresponding parser to a corresponding packetizer based on the generated path information from the path manager 207.

[0042] Accordingly, the streaming data inputted to the DRM transformer 209 and encrypted according to the first DRM algorithm DRMl is partially parsed by a plurality of the parsers and encrypted by the DRMl encrypter. Then, the encrypted streaming data is transferred to the corresponding packetizer, the transferred data is packetized, the packetized data is encrypted by the DRM2 encrypter, and the encrypted data is outputted. Therefore, the DRM algorithm applied to the streaming data is transferred from the first DRM algorithm DRMl to the second DRM algorithm DRM2.

[0043] Fig. 3 is a block diagram illustrating the DRM transformer 209 of Fig. 2. [0044] Referring to Fig. 3, the DRM transformer 209 includes a plurality of parsers and a plurality of packetizers, which are provided by the parsing and packetizing manager 203. As shown, a plurality of the parsers include a first parser, a second parser, ..., a (N_Par)^th parser, and a N^th parser, and a plurality of the packetizers includes a first packetizer, a second packetizer, a (N_par)^th packetizer, and a N^th packetizer. Streaming data with no DRM applied is parsed to original data through the N parsers. The original data is packetized to streaming data through the N packetizers. In general, the parsing steps and the packetizing steps are performed in a reverse order, and the DRM transformer includes the same number of the parsers and the packetizers . [0045] In other words, since the N parsers sequentially parse streaming data to original data, and the N packetizers correspond to the N parsers, the DRM transformer 209 can be described as to have N levels of parsers and packetizers. [0046] As shown in Fig. 3, the DRM transformer 209 according to the present embodiment includes the (N_par)^th parser connected to the DRMl decrypter among the N parsers and the (N_pac)^th packetizer connected to the DRM2 encrypter among the N packetizers. That is, N_par is smaller than N_pac. Herein, N_par denotes the (N_par)^th level when parsers are sequentially counted from the streaming data to the original data, and N_pac denotes the (N_pac)^th level . [0047] The streaming data inputted to the DRM transformer 209 and encrypted according to the DRMl algorithm is parsed until the parsing step performed in the (N_par)^th parser.

[0048] After the (N_par)^th parser parsed the streaming data, the intermediate data generated from the (N_par)^th parser is transferred to the DRM decrypter. The DRMl decrypter decrypts the received intermediate data from the (N_par)^th parser using the first DRM algorithm DRMl. Then, the DRMl decrypter returns the decrypted intermediate data to the (N_par) ^th parser. Therefore, the streaming data encrypted according to the first DRM algorithm is decrypted.

[0049] After the DRMl decrypter returns the decrypted intermediate data to the (N_par)^th parser, the decrypted intermediate data is parsed until a parser corresponding to the (N_pac)^th packetizer, that is, the (N_par)^th parser.

[0050] After the (N_par)^th parser parses the intermediate data, the (N_par)^th parser transfers the parsed intermediate data to a corresponding packetizer, that is, (N_pac)^th packetizer. [0051] The path information generated from the path manager 207 enables the (N_pac)^th parser to transfer the intermediate data to the (N_pac)^th packetizer. [0052] The path manager 207 extracts N_par from information about the DRMl decrypter provided from the DRM manager 205 by analyzing information about the intermediate data decrypted the DRMl decrypter among intermediate data outputted from a plurality of the parsing steps. [0053] The path manager 207 extracts N_pac from the information about the DRM2 encrypter from the DRM manager 205 by analyzing information about intermediate data encrypted by the DRM2 encrypter among a plurality of packetizing steps.

[0054] The path manager 207 compares the extracted N_par with the extracted N_pac and generates path information to transfer intermediate data generated from a parser having the larger variable to a corresponding packetizer. [0055] That is, the path manager 207 generates path information to enable a (N_tr)^th parser among a plurality of parsers to transfers data decrypted by the decrypter to (N_tr)^th packetizer that is corresponding to the (N_tr)^th parser. If the N_par is smaller than the N_pac as shown in Fig. 3, the N_tr is identical to N_pac.

[0056] If the Np_ar is smaller than the N_pac as shown in Fig. 3, the path manager 207 generates path information to enable the (N_pac)^th parser to transfer (N_pac) ^th parsed data to a corresponding packetizer, that is, the (N_pac)^th packetizer based on information about the DRMl decrypter and the DRM2 encrypter, which is provided from the DRM manager 205. Based on the generated path information, the (N_pac)^th parser transfers the intermediate data to the (N_pac)^th packetizer.

[0057] The (N ^fp_pa_dc_C)^th parsed data is transferred to the DRM2 encrypter, which is transferred from the (N_pac)^th parser to the (N_pac)^th packetizer. The DRM2 encrypter encrypts the (N_pac)^th parsed intermediate data using the second DRM algorithm, and returns the encrypted intermediate data to the (N_pac)^th packetizer. Therefore, the streaming data is encrypted according to the second DRM algorithm DRM2. [0058] The (N_pac)^th packetizer receives the encrypted intermediate data from the DRM2 encrypter and packetizes the received intermediate data.

[0059] Fig. 4 is a block diagram illustrating a DRM transformer of MPEG-2 streaming data in accordance with an embodiment of the present invention. [0060] As shown in Fig. 4, the DRM transformer 209 includes four parsers and four packetizers. The first parser 301 parses a user datagram protocol (UDP) packet to a transport stream TS, the second parser 302 parses the TS to a packetized element stream PES, the third parse 303 parses the PES to elementary stream ES, and the fourth parse 304 parse the ES to original data such as video signal or audio signal. The first packetizer 415 packetizes TS to a UDP packet, the second packetizer 413 packetizes PES to TS, the third packetizer 409 packetizes ES to PES, and the fourth packetizer packetizes original data to ES.

[0061] The four parsers and the four packetizers are provided by the parsing and packetizing manager 203 based on streaming format information MEPG-2 recognized by the recognizer 201.

[0062] As shown in Fig. 4, the second parser 403 is connected to the DRMl decrypter 405 among the four parsers, and the third packetizer 409 is connected to the DRM2 encrypter 411 among the four packetizers. [0063] The DRMl decrypter 405 and the DRM2 encrypter 411 are provided by the DRM manager 205 based on a DRM algorithm recognized by the recognizer 201. [0064] The streaming data, which is inputted to the DRM transformer 209 and encrypted according to the DRMl algorithm, is parsed until the parsing step performed in the second parser 403.

[0065] After the second parser 403 parses data, the second parser 304 transfers PES to the DRMl decrypter 405. The DRMl decrypter 405 decrypts the PES received from the second parser 403 using the first DRM algorithm DRMl and returns the decrypted PES to the second parser 403. Therefore, the streaming data is decrypted according to the first DRM algorithm. [0066] The PES returned from the DRMl decrypter 405 to the second parser 403 is parsed until the parsing step performed at the third parser 407 corresponding to the third packetizer 409.

[0067] After the third parser 407 parses the data, the third parser 407 transfers ES to the third packetizer 409 corresponding to the third parser 407. [0068] Based on the path information generated by the path manager 207, the third parser 407 can transfer the ES to the third packetizer 409.

[0069] The path manager 207 determines whether intermediate data PES outputted from the DRMl decrypter 405 is decrypted or not based on the information about the DRMl decrypter, which is provided from the DRM manager 205. [0070] The path manager 207 determines whether the DRM2 encrypter 411 encrypts the intermediate data ES outputted among a plurality of the packetizing steps based on the information about the DRM2 encrypter, which is provided from the DRM manager 205. [0071] The path manager 207 generates path information to enable the third parser 407 to transfer ES parsed by the third packetizer 409 to the third packetizer 409 based on the information about the DRMl decrypter 405 and the DRM2 encrypter 411 which are provided from the DRM manager 205. Using the generated path information, the third parser 407 can transfer the path information to the third packetizer 409.

[0072] Then, the DRM2 encrypter 411 receives the ES parsed by the third parser, encrypts the received ES using the second DRM algorithm DRM2, and returns the encrypted data to the third packetizer 409. Finally, the streaming data is encrypted using the second DRM algorithm.

[0073] The ES, which is returned from the DRM2 encrypter 411 and encrypted according to the DRM2 algorithm, is packetized, thereby finally generating the streaming data. [0074] Fig. 5 is a block diagram illustrating a DRM transformer 209 shown in Fig. 2. Unlike the DRM transformer of Fig. 3, N_par is larger than N_pac in the DRM transformer of Fig. 5. [0075] As a generalized case, the path manager 207 generates path information to enable a (N_tr)^th parser among a plurality of parsers to transfer data decrypted by the decrypter to a (N_tr)^th packetizer. When N_par is larger than N_pac as shown in Fig. 5, N_tr is identical to N_par.

[0076] The streaming data inputted to the DRM transformer 209 and encrypted according to the first DRM algorithm DRMl is parsed until the parsing step performed by the (N_Par)^th parser. [0077] After the (N_par)^th parser parses the streaming data, the (N_par)^th parser transfers the (N_par)^th time parsed intermediate data to the DRMl decrypter. The DRMl decrypter decrypts the intermediate data from the (N_par)^th parser using bhe first DRM algorithm DRMl and returns the decrypted intermediate data to the (N_par)^th parser. Therefore, the streaming data encrypted according to the first DRM algorithm DRMl is decrypted.

[0078] After the (N_par) ^th parser parses the intermediate data, the (N_par)^th parser transfers parsed intermediate data to a corresponding packetizer, that is, the (N_par)^th packetizer.

[0079] The path information generated from the path manager 207 enables the (N_par)^th parser to transfer the intermediate data to the (N_par) ^th packetizer. [0080] The path manager 207 extracts N_par from the information about the DRMl decrypter provided from the DRM manager 205 by detecting decrypted intermediate data among intermediate data outputted from a plurality of the parsing steps. [0081] The path manager 207 extracts N_pac from the information about the DRM2 encrypter provided from the DRM manager 205 by detecting which intermediate data is encrypted among intermediate data outputted from a plurality of the packetizing steps. [0082] The path manager 207 compares the extracted N_par with N_pac and generates path information to transfer intermediate data generated from a parser of the larger variable to a corresponding packetizer.

[0083] As shown in Fig. 5, N_par is larger than N_pac. Therefore, the path manager 207 generates path information to enable the (N_par)^th parser to transfer the

(N_Par)^th parsed intermediate data to a corresponding packetizer, that is, the (N_par)^th packetizer based on the information about the DRMl decrypter and the DRM2 encrypter, which is provided from the DRM manager 205. Using the generated path information, the (N_par)^th parser can transfers the intermediate data to the (N_par)^th packetizer . [0084] The (N_par)^th packetizer receives the (N_par)^th parsed data from the (N_par)^th parser and packetizes the received data.

[0085] The (N_Par)^th packetizer transfers the packetized intermediate data to the DRM2 encrypter. The DRM2 encrypter encrypts the packetized intermediate data using the second DRM algorithm DRM2. After encryption, the DRM2 encrypter returns the encrypted intermediate data to the (N_pac)^th packetizer. Therefore, the streaming data is encrypted according to the second DRM algorithm DRM2. [0086] When the (N_pac)^th packetized intermediate data is transferred to the DRM2 encrypter, the DRM2 encrypter encrypts (N_pac)^th packetized intermediate data from the (Np_ac) ^th packetizer. Then, the DRM 2 encrypter returns the encrypted intermediate data to the (N_pac)^th packetizer. Finally, the streaming data is encrypted according to the second DRM algorithm DRM2.

[0087] The intermediate data, which is returned to the (N_pac)^th packetizer and encrypted according to the second DRM algorithm DRM2, is packetized again. [0088] Fig. 6 is a flowchart illustrating a method for changing a DRM algorithm of streaming data in accordance with an embodiment of the present invention. [0089] As shown in Fig. 6, the recognizer 201 recognizes streaming formats and DRM algorithms of a DRMl based streaming service and a DRM2 based streaming service, which are objects to transform at step S601.

[0090] The parsing and packetizing manager 203 stores and manages various parsers and packetizers for different streaming formats such as MPEG-2 and ISMA, and provides corresponding parsers and packetizers based on the recognized streaming format information from the recognizer 201 at step S603.

[0091] The DRM manager 205 provides information about the DRMl decrypter and the DRM2 encrypter at step S607. [0092] The path manager 207 generates path information based on the information about the DRMl decrypter and the DRM2 encrypter, which is provided from the DRM manager 205 at step S607. The path information denotes information about the- type of the intermediate data to transfer the packetizer. [0093] At step S609, the streaming data inputted to the DRM transformer 209 and encrypted according to the first DRM algorithm DRMl is partially parsed by a plurality of parsers and decrypted by the DRMl decrypter according to the generated path information from the path manager 207. Then, the decrypted data is transferred to a corresponding packetizer, packetized, encrypted by the DRM2 encrypter, and outputted at step S611. Therefore, the DRM algorithm applied to the streaming data is changed from the first DRM algorithm DRMl to the second DRM algorithm DRM2.

[0094] The above described method according to the present invention can be embodied as a program and stored on a computer readable recording medium. The computer readable recording medium is any data storage device that can store data which can be thereafter read by the computer system. The computer readable recording medium includes a read-only memory (ROM) , a random-access memory (RAM) , a CD-ROM, a floppy disk, a hard disk and an optical magnetic disk. [0095] While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims,

INDUSTRIAL APPLICABILITY

[0096] The present invention described above makes it possible to use streaming services encrypted based on diverse DRMs with diverse DRM client terminals.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for changing a first Digital Rights Management (DRM) algorithm DRMl applied to streaming data into a second DRM algorithm DRM2, comprising:

N levels of parsing means for receiving the streaming data and parsing the received streaming data;

N levels of packetizing means for generating the streaming data by packetizing the data parsed by the N levels of parsing means; a decrypting means connected to an n^th level of a parsing means among the N levels of the parsing means and decrypting data parsed by the n^th level of the parsing means according to the first DRM algorithm, where n is an integer smaller than N; an encrypting means connected to an m^th level of a packetizing means among the N levels of the packetizing means and encrypting data decrypted by the decrypting means according to the second DRM algorithm; and a path managing means for managing a path based on the n value and the m value in order to parse and packetize the streaming data with a minimum number of the parsing means and the packetizing means.

2. The apparatus of claim 1, wherein the path managing means has the streaming data parsed and packetized by a parsing means and a packetizing means with a level of a value greater between the n and m values .

3. The apparatus of claim 1, wherein the n^th level is decided based on the first DRM algorithm and the m^th level is decided based on the second DRM algorithm.

4. The apparatus of claim 1, further comprising: a recognizing means for recognizing streaming format information of the streaming data.

5. The apparatus of claim 4, further comprising: a parsing and packetizing managing means for storing parsing means and packetizing means according to various streaming formats, wherein the N levels of parsing means and packetizing means are provided based on the streaming format information recognized by the recognizing means.

6. The apparatus of claim 1, further comprising: a recognizing means for recognizing information about the first DRM algorithm and the second DRM algorithm.

7. The apparatus of claim 6, further comprising: a DRM managing means for storing encrypting means and decrypting means according to various DRM algorithms, wherein the encrypting means and the decrypting means are provided by the DRM managing means based on the information about the first DRM algorithm and the second DRM algorithm, which is recognized by the recognizing means .

8. The apparatus of claim 7, wherein the path managing means generates the path information based on the information about the decrypting means and the encrypting means, which is provided from the DRM managing means .

9. A method for changing a first DRM algorithm applied to streaming data into a second DRM algorithm, comprising the steps of: receiving the streaming data and parsing the streaming data in N levels; generating the streaming data by packetizing the parsed data through the parsing process in N levels; decrypting the parsed data of an n^th level among the N level parsing steps according to the first DRM algorithm, where n is an integer smaller than N; encrypting data, which is obtained from the decryption process, according to the second DRM algorithm to be packetized in an m^th level packetizing step among the N levels of packetizing steps, where m is an integer smaller than N; and managing a path to parse and packetize the streaming data through a minimum number of parsing steps and packetizing steps based on the n value and the m values .

10. The method of claim 9, wherein in the path managing step, the streaming data is parsed or packetized by a parsing step and a packetizing step with a level of a greater value between the n and m values.

11. The method of claim 9, wherein the n^th level is decided based on the first DRM algorithm, and the m^th level is decided based on the second DRM algorithm.

12. The method of claim 9, further comprising the step of: recognizing a streaming format of the streaming data.

13. The method of claim 12, wherein the N levels of the parsing steps and the packetizing steps are decided based on the streaming format information recognized in the recognizing step.

14. The method of claim 9, further comprising the step of: recognizing the first DRM algorithm and the second DRM algorithm.

15. The method of claim 14, wherein the decrypting step and the encrypting step are decided based on the first DRM algorithm and the second algorithm which are recognized in the recognizing step.

16. The method of claim 15, wherein in the path managing step, the path information is generated in the decrypting step and the encrypting step, which are decided by the first DRM algorithm and the second DRM algorithm.