KR20100096484A - Mobile conditional access system based on software for bandwidth enhancement - Google Patents

Abstract

PURPOSE: A mobile conditional access system based on software for increasing bandwidth is provided to support a safe CAS service based on software in a unidirectional mobile terminal. CONSTITUTION: A CAS(Conditional Access System) server(100) transmits an EMM(Entitlement Management Message) and an ECM(Entitlement Control Message) including a key related to authentication. The CAS server includes an encoded CW(Control Word) and the EMM in the ECM and transmits it. A CAS client(200) decodes an encoded public key of the CAS server extracted from the EMM and the encoded CW extracted from the ECM.

Description

Software-based Mobile Restriction System for Bandwidth Enhancement {MOBILE CONDITIONAL ACCESS SYSTEM BASED ON SOFTWARE FOR BANDWIDTH ENHANCEMENT}

The present invention relates to a software-based mobile reception restriction system for improving bandwidth, and in particular, by including and transmitting an Entitlement Management Message (EMM) in an Entitlement Control Message (ECM), thereby improving bandwidth to minimize bandwidth due to EMM transmission. The present invention relates to a software-based mobile reception limiting system.

CAS (Conditional Access System) is a broadcasting reception restriction system that provides broadcasting service only to subscribers who have the right to watch broadcasting for satellite / terrestrial digital multimedia broadcasting.The core message protocol is EMM (Transmission Authority and User Key). There is an Entitlement Management Message (ECM) and an Entitlement Control Message (ECM) that delivers an encryption key used to decrypt an encrypted broadcast.

1 is a road schematically illustrating a satellite / terrestrial digital multimedia broadcasting (DMB) reception restriction system according to the prior art, and an EMM (Entitlement Management Message) generation and transmission unit of a CAS server is generated by a CWEK (Control Word Encrypt Key) generation unit. Generates an EMM by encrypting the CWEK with a Unique Subscriber Key (USK), sends the generated EMM to the CAS client, and generates and transmits an Entitlement Control Message (ECM) to the CWEK. The ECM is generated by encryption, and the generated ECM is transmitted to the CAS client, and the scrambler scrambles the video / audio / data stream (TS packet) to be transmitted to the CAS client to the CW client.

On the other hand, when the CAS client receives the EMM from the CAS server, the EMM decryption and analysis unit decrypts the EMM with a USK previously issued and stored in a smart card, acquires CWEK, and analyzes the decrypted EMM. To verify the legitimacy of user rights. When the user confirms that the user is a legitimate user, when receiving the ECM from the CAS server, the ECM decoding and analysis unit decrypts the ECM with CWEK, obtains the CW, and analyzes the decrypted ECM. After checking the legitimacy of the user's authority, if the user is confirmed as a legitimate user, the CW included in the decrypted ECM is authorized as the descrambler, and the descrambler receives the scrambled video / audio / data received from the CAS server. A procedure of watching a broadcast is performed by descrambling a stream to CW.

As described above, when transmitting an EMM carrying broadcast authority and a user key from a CAS server to a CAS client, the conventional EMM must be transmitted to subscribers of each individual occupying a large amount of bandwidth.

As such, since the amount of the EMM bandwidth is proportional to the number of subscribers, more bandwidth is required as the number of subscribers increases, which causes a problem that the processing efficiency of the transmitting side is greatly reduced.

Due to the problems as described above, the conventional CAS system has a problem that the service efficiency is lowered because the high speed processing can not be performed at the time of service support.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and includes a software-based mobile reception limiting system for improving bandwidth to minimize the bandwidth according to the EMM transmission by including the EMM in the ECM and transmitting the scrambled data together. The purpose is to provide.

It is another object of the present invention to encrypt a CW (Control Word) used for broadcasting content encryption and transmit it by embedding it in an ECM, thereby enabling software-based mobile reception for bandwidth enhancement to support secure CAS services based on software in one-way mobile terminals. To provide a limiting system.

According to an embodiment of the present invention, a software-based mobile reception limiting system for improving bandwidth may transmit an EMM and an ECM including a key related to authentication to use broadcast content in an authenticated CAS client. A CAS server for transmitting a Transport Stream (TS) packet including broadcast content, encrypting a CW used to encrypt the TS packet, and transmitting the encrypted CW and the EMM in the ECM; The ECM and encrypted TS packets received from the CAS server are processed, and the public key of the encrypted CAS server extracted from the EMM included in the ECM is a public key cryptographic algorithm having a decoded digital signature function. And a CAS client for decrypting each of the encrypted CWs, and obtaining a public key and CW of a CAS server necessary for CAS service operation, and decrypting the encrypted TS packet received from the CAS server using the CW. desirable.

The CAS server may further include: a CAS DB storing subscriber information (SID) issued for each CAS client from a subscriber information issuing system; A security rule generator for generating a subscriber key (USK) using subscriber information (SID) received from the CAS DB; The subscriber key USK and the subscriber information SID are received together from the security rule generator, the public key CSpuk of the CAS server is encrypted using the subscriber key USK, and the subscriber information SID is encoded. An EMM generator for generating an EMM using an encrypted public key (Eusk (CSpuk)) and encoded subscriber information (TSID); A CW generator for generating CW using an arbitrary random number method; An ECM generator that encrypts the CW received from the CW generator with a private key (CSprk) of a CAS server and generates an ECM using an encrypted CW (Ecsprk (CW)) and the EMM received from the EMM generator. Wow; After scrambled the TS packet to the CW, it is preferable that the scrambled TS packet and the ECM received from the ECM generation unit is connected to the scrambler to transmit to the CAS client.

The CAS server includes: a public key and private key pair generation unit for generating a public key CSpuk and a private key CSprk of the CAS server; A public key and private key pair storage unit for storing the public key CSpuk and the private key CSprk; Preferably, the control unit further comprises a key change cycle management unit which controls the public key and private key pair generation unit to periodically change the public key CSpuk and the private key CSprk.

In addition, when including and transmitting at least two or more EMMs in the ECM, the CAS DB of the CAS server delivers at least two subscriber information (SID) to the security rule generator, and the security rule generator is each subscriber. After generating the subscriber key (USK) corresponding to the information (SID), each subscriber information (SID) and the subscriber key (USK) corresponding to the subscriber information (SID) are paired and delivered to the EMM generator, When the EMM generation unit receives at least two or more subscriber information (SID) and subscriber key (USK) pairs from the security rule generation unit, encrypts the public key (CSpuk) of the CAS server with each subscriber key (USK), After encoding each subscriber information (SID), at least two EMMs are generated by using each encrypted public key (Eusk (CSpuk)) and encoded subscriber information (TSID) pairs, and the generated EMM is ECM Deliver to the generation unit, the ECM generation unit CA The CW is encrypted with the private key CSprk of the S server, and the ECM is generated using the encrypted CW (Ecsprk (CW)) and at least two EMMs received from the EMM generator.

In addition, when transmitting only the encrypted CW (Ecsprk (CW)) without including the EMM in the ECM, the ECM generation unit of the CAS server receives the CW from the CW generation unit as a public key (CSprk) of the CAS server. It is desirable to encrypt, generate an ECM using an encrypted CW (Ecsprk (CW)), and transmit the generated ECM to the CAS client through the scrambler.

The subscriber information issuing system issues subscriber information (SID) for each CAS client and delivers the issued subscriber information (SID) to the CAS server through a SSL / TLS (Secure Socket Layer / Transport Layer Security) mechanism. Meanwhile, it is preferable to encode the subscriber information (SID), re-encrypt the encoded SID (TSID) with a password input from the subscriber, and then transmit the encrypted TSID (Epsw (TSID)) to the CAS client.

The CAS client may include a message and packet receiving unit configured to receive the ECM and the scrambled TS packet from the CAS server; A subscriber information storage unit for receiving and storing an encrypted TSID (Epsw (TSID)) from a subscriber information issuing system for issuing subscriber information (SID) for each CAS client in advance; Decrypt the TSID obtained by decrypting the encrypted TSID (Epsw (TSID)) with a password inputted from a subscriber who is allowed to access through a login module, and the TSID received from the message and packet receiving unit, respectively. A subscriber information decryption and verification unit for comparing and matching two subscriber information (SID); A security rule generator for generating a subscriber key (USK) using subscriber information (SID) verified by the subscriber information decryption and verification unit; An EMM decryption and analysis unit for decrypting an encrypted public key (Eusk (CSpuk)) included in the EMM received from the message and packet receiver with the subscriber key (USK) received from the security rule generator; An ECM decryption and analysis unit for decrypting an encrypted CW (Ecsprk (CW)) included in the ECM received from the message and packet receiver with a public key (CSpuk) received from the EMM decryption and analysis unit; And a descrambler configured to descramble the scrambled TS packet received through the message and packet receiver to the CW received from the ECM decoder and analyzer.

In addition, the CAS client, the public key storage unit for receiving and storing the encrypted public key (Eusk (CSpuk)) from the EMM decryption and analysis unit; Decrypt the encrypted public key (Eusk (CSpuk)) received from the public key storage unit with the subscriber key (USK) received from the security rule generator, and decrypt and analyze the ECM decrypted public key (CSpuk). It further comprises a public key decryption unit for transmitting to the public, the EMM decryption and analysis unit, the public key (CSpuk) decrypted by the EMM decryption and analysis unit back to the subscriber key (USK) received from the security rule generation unit After encryption, it is preferable to store an encrypted public key (Eusk (CSpuk)) in the public key storage unit.

The message and packet receiving unit transmits the scrambled TS packet received from the CAS server to the descrambler, analyzes the ECM, and extracts the EMM from the ECM if the ECM is included in the ECM. The EMM transfers the extracted ECM to the ECM decryption and analysis unit, analyzes the EMM extracted from the ECM to extract a TSID from the EMM, transfers the extracted TSID to the subscriber information decryption and verification unit, and extracts the TSID. The EMM is preferably transmitted to the EMM decoding and analyzing unit.

The subscriber information decryption and verification unit receives an encrypted TSID (Epsw (TSID)) and a password from the subscriber information storage unit, and decrypts the encrypted TSID (Epsw (TSID)) with the password to obtain a TSID. A subscriber information decryption module; Decode the TSID received from the subscriber information decoding module through a decoding module to obtain an SID, decode the TSID received from the message and packet receiver through the decoding module to obtain an SID, and then obtain the SID. Comparing one or two SIDs to verify whether the match, and if the two SIDs match, it is preferable to include a verification module for transmitting the SID to the security rule generation unit.

If the ECM includes at least two EMMs for transmission, the message and packet receiver of the CAS client extracts at least two EMMs from the ECM, and then extracts a TSID from each extracted EMM. Transmits the received TSID to the subscriber information decryption and verification unit, and the subscriber information decryption and verification unit decrypts at least two or more TSIDs received from the message and packet receiving unit, respectively, to obtain at least two subscriber information (SID); At least two or more subscriber information (SIDs) obtained by decrypting a TSID obtained by decrypting an encrypted TSID (Epsw (TSID)) received from the subscriber information storage unit with a decryption module. ), The subscriber information (SID) that matches each other is preferably delivered to the security rule generator.

When transmitting only the encrypted CW (Ecsprk (CW)) without including the EMM in the ECM, the message and packet receiver of the CAS client transmits the ECM to the ECM decryption and analysis unit, and decrypts the subscriber information. And the verification unit decrypts the encrypted TSID (Epsw (TSID)) received from the subscriber information storage unit with a password input from an access-accessible subscriber to obtain a TSID, and decrypts the obtained TSID with a decryption module again. After acquiring the information SID, the subscriber information SID is transmitted to the security rule generator, and the security rule generator generates a subscriber key USK using the subscriber information SID, and generates the subscriber key. (USK) is transmitted to the public key decryption unit, and the public key decryption unit decrypts the encrypted public key (Eusk (CSpuk)) stored in the public key storage unit with the subscriber key (USK). The public key (CSpuk) is transmitted to the ECM decryption and analysis unit, and the ECM decryption and analysis unit transmits the encrypted CW (Ecsprk (CW)) included in the ECM received from the message and packet receiver. After decrypting with the public key CSpuk received from the decryption unit, it is preferable to transmit the decrypted CW to the descrambler.

According to the software-based mobile reception restriction system for improving the bandwidth of the present invention, since the EMM is inserted into the ECM and transmitted, the bandwidth according to the EMM transmission can be minimized, thereby increasing the transmission efficiency.

In addition, since the CW is encrypted instead of the ECM and then transmitted to the ECM, the secure CAS service can be supported based on software in the unidirectional mobile terminal.

Hereinafter, a software-based mobile reception restriction system for improving bandwidth according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram schematically illustrating a configuration of a software-based mobile reception restriction system for improving bandwidth according to an embodiment of the present invention.

In FIG. 2, the CAS server 100 includes a CAS DB 110, a key change cycle manager 120, a public key and private key pair generator 130, a public key and private key pair storage DB 140, and a security rule. The generator 150, the EMM generator 160, the ECM generator 170, the CW generator 180, and the scrambler 190 are included.

In such a configuration, the CAS DB 110 receives a subscriber ID (SID), which is subscriber information issued for each CAS client 200, from the subscriber information issuing system 10 (SMS) (subscriber management system (SMS) 20). Received through and stored for each CAS client (200).

That is, the broadcast service subscriber accesses the subscriber information issuing system 10 through a web browser and registers information about the subscriber. When the subscriber accesses the subscriber information issuing system 10 and registers information about the subscriber, The subscriber information issuing system 10 automatically issues SID (for example, SID1), which is the only subscriber information, and securely stores the issued SID1 through the SSL / TLS (Secure Socket Layer / Transport Layer Security) mechanism. After transmitting to the CAS DB 110 of 100, the SID1 is coded, and then the encoded SID1 (TSID1) is encrypted with a password input by the subscriber through an encryption algorithm, and encrypted TSID1 (Epsw (TSID1)). To securely deliver to the CAS client 200.

As described above, the CAS DB 110 may transmit the broadcast content to the subscriber under the control of the Traffic Control System (TCS) 30, and the subscriber information of the subscriber to which the broadcast content is to be transmitted (for example, SID1). ) Is transmitted to the security rule generator 150.

On the other hand, the public key and private key pair generation unit 130 generates a public key (CSpuk) and a private key (CSprk) of the CAS server 100 and stores the public key and private key pair storage DB 140, The key CSprk is encrypted using a cryptographic algorithm and stored securely.

The public key and private key pair generation unit 130 may change the public key CSpuk and the private key CSprk of the CAS server 100 periodically under the control of the key change period management unit 120.

Public key and private key pair storage DB 140 stores a public key (CSpuk) and a private key (CSprk) pair received from the public key and private key pair generation unit 130, and generates an EMM for generating an EMM. The public key CSpuk is transmitted to the unit 160, and the private key CSprk is transmitted to the ECM generator 170 for ECM generation.

Meanwhile, the security rule generator 150 generates a subscriber key (eg, USK1) by using subscriber information (eg, SID1) received from the CAS DB 110, and generates the generated subscriber key (USK1). And the subscriber information (SID1) received from the CAS DB 110 as a pair and transmitted to the EMM generation unit 160.

The EMM generation unit 160 receives the public key (CSpuk) received from the public key and private key pair storage DB 140 using the subscriber key USK1 received along with the subscriber information SID1 from the security rule generation unit 150. ), The subscriber information (SID1) is coded through the Encoding Module (165), and then the EMM is encrypted using the encrypted public key (Eusk1 (CSpuk)) and the encoded subscriber information (TSID1 '). Generates and transmits the generated EMM to the ECM generator 170.

The ECM generation unit 170 is a public key cryptographic algorithm having a decoded digital signature function, and uses the CW generated by the CW generation unit 180 as the private key (CSprk) received from the public key and private key pair storage DB 140. Encrypts, generates an ECM to be transmitted to the subscriber by using the encrypted CW (Ecsprk (CW)), EMM, Cr (Crypto Period Info) and AC (Access Criteria) received from the EMM generator 160, the generated ECM To the scrambler 190.

The CW generator 180 generates a CW to be used for scrambling a transport stream (TS) packet to be transmitted to a subscriber by using an arbitrary random number generation method, and generates the CW to the ECM generator 170 and the scrambler 190. To pass.

The scrambler 190 scrambles a TS packet including a video / audio / data stream, which is broadcast content to be transmitted to a subscriber, by using the CW received from the CW generator 180, and then scrambled the TS packet and the ECM generator 170. ECM received from the concatenated and transmits together to the CAS client (200).

Meanwhile, the CAS client 200 may include a subscriber information storage 210, a login module 205, a subscriber information decryption and verification unit 220, a message and packet receiver 230, a security rule generator 240, and an EMM decryption. And an analysis unit 250, an ECM decryption and analysis unit 260, a descrambler 270, a public key storage unit 280, and a public key decryption unit 290.

In such a configuration, the subscriber information storage unit 210 receives and stores the encrypted TSID1 (Epsw (TSID1)) from the subscriber information issuing system 10, and stores the encrypted TSID1 (Epsw (TSID1)) from the subscriber logged in through the login module 205. The received password is transmitted to the subscriber information decryption module 223 of the subscriber information decryption and verification unit 220 together with the encrypted TSID1 (Epsw (TSID1)).

As described above, the subscriber information issuing system 10 stores the SID (for example, SID1), which is the only subscriber information issued for each CAS client 200, securely through the SSL / TLS mechanism in the CAS DB of the CAS server 100. On the other hand, after SID1 is coded, the encoded SID1 (TSID1) is encrypted with a password input by the subscriber through an encryption algorithm, and the encrypted TSID1 (Epsw (TSID1)) is encrypted by the CAS client 200. To deliver safely.

The login module 205 allows a subscriber who has logged in using a One Time Password (OTP) of a mobile terminal on which the CAS client 200 is installed, and accesses the subscriber information storage unit 210, while receiving a password input from the subscriber. The securely transmitted to the subscriber information decryption and verification unit 220 through the subscriber information storage unit 210.

Meanwhile, the subscriber information decryption and verification unit 220 decrypts the encrypted TSID1 (Epsw (TSID1)) received from the subscriber information storage unit 210 with a password, and TSID1 received from the message and packet receiving unit 230. We compare two SID1s obtained by decoding each and verify whether the two values match.

As described above, the subscriber information decoding and verification unit 220 includes a subscriber information decoding module 223, a verification module 225, and a decoding module 227.

In this case, when the subscriber information decryption module 223 receives the encrypted TSID1 (Epsw (TSID)) and the password from the subscriber information storage unit 210, the encrypted TSID1 (Epsw (TSID1)) is decrypted with the password to TSID1. Is obtained, and the obtained TSID1 is transmitted to the verification module 225.

The verification module 225 decodes TSID1 received from the subscriber information decoding module 223 through the decoding module 227 to obtain SID1, and decodes TSID1 'received from the message and packet receiving unit 230. After decoding through SID1 to obtain the SID1, and comparing the two SID1 obtained through the decoding module 227 to verify whether the two SID1 is the same, if the two SID1 is the same SID1 obtained through the decoding module 227 It is delivered to the security rule generation unit 240.

Meanwhile, the message and packet receiver 230 receives the ECM and the scrambled TS packet from the CAS server 100, transfers the received scrambled TS packet to the descrambler 270, and analyzes the received ECM to the ECM. If the EMM is included, after the EMM is extracted from the ECM, the EMM extracts the extracted ECM to the ECM decoding and analyzing unit 260. After analyzing the EMM extracted from the ECM and extracting TSID1 'from the EMM, the extracted TSID1' is transferred to the subscriber information decryption and verification unit 220, and the extracted EMM TSID1 'is transmitted to the EMM decryption and analysis unit 250. To pass.

The security rule generator 240 generates a subscriber key USK1 using the SID1 received from the verification module 225 of the subscriber information decryption and verification unit 220, and generates the subscriber key USK1 by the EMM decryption and analysis unit 250. To pass).

When the EMM decryption and analysis unit 250 receives the EMM from the message and packet receiver 230, the EMM decryption and analysis unit 250 receives the encrypted public key (Eusk1 (CSpuk)) included in the received EMM from the security rule generator 240. After decrypting with the subscriber key USK1, the decrypted public key CSpuk is transmitted to the ECM decryption and analysis unit 260, while the decrypted public key CSpuk is received from the security rule generator 240. Encrypted again, the encrypted public key (Eusk1 (CSpuk)) is stored in the public key storage unit 280.

When the ECM decryption and analysis unit 260 receives the ECM from the message and packet receiving unit 230, the ECM decryption and analysis unit 250 receives the encrypted CW (Ecsprk (CW)) included in the received ECM from the EMM decryption and analysis unit 250. After decrypting with a public key (CSpuk) of a public key cryptographic algorithm having a decrypted digital signature function, the decrypted CW is transmitted to the descrambler 270.

The descrambler 270 descrambles the scrambled TS packet received through the message and packet receiver 230 to the CW received from the ECM decoder and analyzer 260, and then delivers the descrambled TS packet to the media player. do.

The above-described subscriber information decryption and verification unit 220, message and packet receiver 230, security rule generator 240, EMM decryption and analysis unit 250, ECM decryption and analysis unit 260, public key decryption The unit 290 and the descrambler 270 are preferably implemented in a secure CAS library mounted on the CAS client side.

3 is a road schematically showing the structure of an ECM generated according to an embodiment of the present invention, the ECM generated according to an embodiment of the present invention is encrypted CW (Ecsprk (CW)) and at least two or more EMMs; It is made to include.

As shown in FIG. 3, when an ECM including an encrypted CW (Ecsprk (CW)) and at least two or more EMMs are to be generated and transmitted, the CAS DB 110 of the CAS server 100 performs video / audio. / Subscriber information (SID) of at least two or more target subscribers to transmit the / data stream to the security rule generator 150, the security rule generator 150 is at least two subscribers received from the CAS DB (110) After generating a subscriber key (USK) corresponding to each subscriber information (SID) using the information (SID), each subscriber information (SID) and a subscriber key (USK) corresponding to the subscriber information (SID) are generated. The pair is transmitted to the EMM generator 160.

When the EMM generation unit 160 receives at least two or more subscriber information (SID) and subscriber key (USK) pairs from the security rule generation unit 150, the EMM generator 160 encrypts the public key CSpuk with each subscriber key USK. After each subscriber information (SID) is coded through the code module 165, at least two EMMs are generated by using an encrypted public key (Eusk (CSpuk)) and a coded subscriber information (TSID) pair. The generated EMM is transmitted to the ECM generator 170.

The ECM generation unit 170 encrypts the CW with the private key CSprk of the CAS server 100, and encrypts the CWs (Ecsprk (CW)) and at least two or more EMMs and CPs received from the EMM generation unit 160. And generate an ECM to be transmitted to the subscriber by using the AC, and transmit the generated ECM to the CAS client 200 along with the scrambled TS packet through the scrambler 190.

Meanwhile, the message and packet receiver 230 of the CAS client 200 receiving the ECM including at least two EMMs from the CAS server 100 extracts at least two or more EMMs from the ECM, and then extracts each of the extracted EMMs. Extracts the TSID and transfers the extracted TSID to the subscriber information decryption and verification unit 220.

The verification module 225 of the subscriber information decryption and verification unit 220 decodes at least two or more TSIDs received from the message and packet receiver 230 through the decoding module 227 to obtain at least two or more SIDs. And comparing the SIDs obtained by decrypting the TSIDs received from the subscriber information decryption module 223 to each other, and comparing the SIDs obtained by decrypting the TSIDs received from the subscriber information decryption module 223 with the security rule generator. Forward to 240.

In this case, the EMM in which the SID corresponding to the SID obtained by decoding the TSID received from the subscriber information decoding module 223 is encoded is included in the EMM to be received by the CAS client 200.

The security rule generator 240 generates one subscriber key USK using one SID received from the verification module 225 of the subscriber information decryption and verification unit 220, and decrypts the generated subscriber key USK with the EMM. Transfer to the analysis unit 250.

The EMM decryption and analysis unit 250 decrypts the encrypted public key (Eusk (CSpuk)) included in the EMM received from the message and packet receiving unit 230 with the subscriber key USK received from the security rule generator 240. The decrypted public key CSpuk is transmitted to the ECM decryption and analysis unit 260.

As described above, the EMM decryption and analysis unit 250 generates a security rule generator 240 for each encrypted public key (Eusk (CSpuk)) included in at least two or more EMMs received from the message and packet receiver 230. Decrypt each of the subscriber key USK received from the subscriber, and only the encrypted public key (Eusk (CSpuk)) included in the EMM containing the SID encoded by the subscriber information decryption and verification unit 220 is the subscriber key USK. Is decrypted by For example, assuming that the SID verified by the subscriber information decryption and verification unit 220 is SID3, only the encrypted public key (Eusk3 (CSpuk)) included in the EMM3 including SID3 is decrypted by the subscriber key USK3. do.

ECM decryption and analysis unit 260 is an encrypted CW (Ecsprk (CW) included in the ECM received from the message and packet receiver 230 using the public key (CSpuk) received from the EMM decryption and analysis unit 250 )), And the decoded CW is transmitted to the descrambler 270.

4 is a road schematically showing the structure of an ECM generated according to another embodiment of the present invention, the ECM generated according to another embodiment of the present invention includes an encrypted CW (Ecsprk (CW)) and one EMM Is done.

As shown in FIG. 4, in the case of generating and transmitting an ECM including an encrypted CW (Ecsprk (CW)) and one EMM, the CAS DB 110 of the CAS server 100 performs video / audio / data. Subscriber information (for example, SID1) of the target subscriber of the person who will transmit the stream is transmitted to the security rule generator 150, and the security rule generator 150 receives the subscriber information (received from the CAS DB 110). After generating the subscriber key USK1 corresponding to the subscriber information SID1 using the SID1, the pair of subscriber information SID1 and the subscriber key USK1 are transmitted to the EMM generator 160.

The EMM generator 160 encrypts the public key CSpuk with the subscriber key USK1 by using the pair of subscriber information SID1 and the subscriber key USK1 received from the security rule generator 150. After the subscriber information (SID1) is coded through the code module 165, one EMM1 is generated using the encrypted public key (Eusk1 (CSpuk)) and the encoded subscriber information (TSID1), and the generated EMM1 is generated. It transmits to the ECM generation unit 170.

The ECM generator 170 encrypts the CW with the private key CSprk of the CAS server 100, and uses the encrypted CW (Ecsprk (CW)) and the EMM1, CP, and AC received from the EMM generator 160. It generates an ECM to be transmitted to the subscriber, and transmits the generated ECM to the CAS client 200 with the scrambled TS packet through the scrambler 190.

Meanwhile, the message and packet receiver 230 of the CAS client 200 receiving the ECM including one EMM from the CAS server 100 extracts TSID1 from the EMM1 extracted from the ECM, and then decodes the extracted TSID1 from the subscriber information. And it passes to the verification unit 220.

The verification module 225 of the subscriber information decoding and verification unit 220 decodes TSID1 received from the message and packet receiving unit 230 through the decoding module 227 to obtain SID1, and acquires the obtained SID1 from the subscriber information decoding module. Compared to SID1 obtained by decrypting TSID1 received from 223, if two SID1s are the same, it is transmitted to the security rule generator 240.

The security rule generating unit 240 generates a subscriber key USK1 using the SID1 received from the verification module 225 of the subscriber information decryption and verification unit 220, and generates the generated subscriber key USK1 using the EMM decryption and analysis unit ( 250).

The EMM decryption and analysis unit 250 decrypts the encrypted public key (Eusk1 (CSpuk)) included in the EMM1 received from the message and packet receiving unit 230 with the subscriber key USK1 received from the security rule generator 240. The decrypted public key CSpuk is transmitted to the ECM decryption and analysis unit 260.

ECM decryption and analysis unit 260 is an encrypted CW (Ecsprk (CW) included in the ECM received from the message and packet receiver 230 using the public key (CSpuk) received from the EMM decryption and analysis unit 250 )), And the decoded CW is transmitted to the descrambler 270.

Figure 5 is a road schematically showing the structure of the ECM generated according to another embodiment of the present invention, ECM generated according to another embodiment of the present invention is encrypted without CW (Ecsprk (CW)) EMM It is made only by including.

As illustrated in FIG. 5, when generating and transmitting an ECM including only an encrypted CW (Ecsprk (CW)) without including an EMM, the ECM generation unit 170 of the CAS server 100 may include a public key and a public key. Using the public key (CSprk) of the CAS server 100 received from the private key pair storage DB 140 encrypts the CW received from the CW generation unit 180, encrypted CW (Ecsprk (CW)), CP And generate an ECM to be transmitted to all subscribers through the unidirectional channel using the AC, and transmit the generated ECM to the CAS client 200 along with the scrambled TS packet through the scrambler 190.

Meanwhile, the message and packet receiver 230 of the CAS client 200 that receives the ECM including only the encrypted CW (Ecsprk (CW)) without the EMM from the CAS server 100 may decode the ECM and receive the received ECM. Transfer to the analysis unit 260.

At this time, the subscriber information decryption module 223 of the subscriber information decryption and verification unit 220 acquires TSID1 by decrypting the encrypted TSID1 (Epsw (TSID1)) received from the subscriber information storage unit 210 with a password. The TSID1 is transmitted to the decryption module 227. The decryption module 277 decrypts TSID1 received from the subscriber information decryption module 223 to obtain SID1, and then transmits the TSID1 to the security rule generator 240. FIG.

The security rule generator 240 generates the subscriber key USK1 using the SID1 and transfers the generated subscriber key USK1 to the public key decryption unit 290.

As described above, the public key decryption unit 290, which has received the subscriber key USK1 from the security rule generator 240, subscribes to the encrypted public key (Eusk1 (CSpuk)) stored in the public key storage unit 280. The key USK1 is decrypted and the decrypted public key CSpuk is transmitted to the ECM decryption and analysis unit 260.

Accordingly, the ECM decryption and analysis unit 260 receives the public key (Ecsprk (CW)) included in the ECM received from the message and packet receiver 230 from the public key decryption unit 290. After decrypting with CSpuk, the decoded CW is transmitted to the descrambler 270.

Software-based mobile reception restriction system for improving the bandwidth of the present invention is not limited to the above-described embodiment and can be implemented in various modifications within the range allowed by the technical idea of the present invention.

1 is a view schematically showing a satellite / terrestrial DMB reception restriction system according to the prior art;

Figure 2 is a schematic view showing the configuration of a software-based mobile reception restriction system for improving bandwidth according to an embodiment of the present invention.

3 is a view schematically showing the structure of an ECM generated according to an embodiment of the present invention.

4 is a schematic view showing a structure of an ECM generated according to another embodiment of the present invention.

5 is a schematic view showing the structure of an ECM generated according to another embodiment of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

100.CAS server, 110.CAS DB,

120. Key change cycle management unit 130. Public and private key pair generation unit,

140. DB for storing public and private key pairs, 150, 240. security rule generator;

160. EMM generator, 165. Sign module,

170. ECM generator, 180. CW generator,

190. Scrambler, 200. CAS client,

205. Login module 210. Subscriber information storage unit,

220. subscriber information decryption and verification unit, 223. subscriber information decryption module,

225. verification module, 227. decoding module,

230. Message and packet receiver, 250. EMM decryption and analysis unit,

260. ECM decryption and analysis unit, 270. descrambler,

280. Public key storage, 290. Public key decryption

Claims (15)

Transport Stream (TS) packet including broadcast content and transmitting an Entitlement Management Message (EMM) and an Entitlement Control Message (ECM) including a key related to authentication to use broadcast content from an authenticated Conditional Access System (CAS) client A CAS server for transmitting the encrypted CW and Control Word (CW) used for encrypting the TS packet, including the encrypted CW and the EMM in the ECM and transmitting the encrypted CW and the EMM; Process the ECM and the encrypted TS packet received from the CAS server, and decrypt the public key of the encrypted CAS server extracted from the EMM included in the ECM and the encrypted CW extracted from the ECM to perform CAS service operation. And a CAS client which obtains a public key and CW of a required CAS server and decrypts an encrypted TS packet received from the CAS server using the CW. The method of claim 1, wherein the CAS server, A CAS DB storing subscriber information (SID: Subscriber ID) issued for each CAS client from the subscriber information issuing system; A security rule generator for generating a subscriber key (USK) using the subscriber information (SID) received from the CAS DB; The subscriber key USK and the subscriber information SID are received together from the security rule generator, the public key CSpuk of the CAS server is encrypted using the subscriber key USK, and the subscriber information SID is encoded. An EMM generator for generating an EMM using an encrypted public key (Eusk (CSpuk)) and encoded subscriber information (TSID); A CW generator for generating CW using an arbitrary random number method; An ECM generator that encrypts the CW received from the CW generator with a private key (CSprk) of a CAS server and generates an ECM using an encrypted CW (Ecsprk (CW)) and the EMM received from the EMM generator. Wow; Software based mobile reception restriction for bandwidth enhancement, characterized in that it comprises a scrambler to scramble the TS packet to the CW, and then concatenate the scrambled TS packet and the ECM received from the ECM generation unit and transmit the scrambler to the CAS client. system. The method of claim 2, wherein the CAS server, A public key and private key pair generation unit for generating a public key CSpuk and a private key CSprk of the CAS server; A public key and private key pair storage unit for storing the public key CSpuk and the private key CSprk; Software-based mobile reception restriction for bandwidth enhancement, further comprising a key change period management unit for controlling the public key and private key pair generation unit to periodically change the public key CSpuk and the private key CSprk. system. The method of claim 2, wherein the EMM generating unit, Software based mobile reception restriction system for bandwidth enhancement, characterized in that it comprises an Encoding Module (Encode Module) for encoding the subscriber information (SID). The method of claim 2, wherein the ECM includes at least two EMMs for transmission. The CAS DB delivers at least two subscriber information (SID) to the security rule generator, The security rule generator generates a subscriber key (USK) corresponding to each subscriber information (SID), and then pairs each subscriber information (SID) and a subscriber key (USK) corresponding to the subscriber information (SID). To the EMM generator, When the EMM generation unit receives at least two or more subscriber information (SID) and subscriber key (USK) pairs from the security rule generation unit, encrypts the public key (CSpuk) of the CAS server with each subscriber key (USK), After encoding each subscriber information (SID), at least two EMMs are generated by using each encrypted public key (Eusk (CSpuk)) and encoded subscriber information (TSID) pairs, and the generated EMM is ECM Deliver to the generator, The ECM generation unit encrypts the CW with the private key CSprk of the CAS server, and generates an ECM using the encrypted CW (Ecsprk (CW)) and at least two EMMs received from the EMM generation unit. Software-based mobile reception system for improving bandwidth. The method of claim 2, wherein when transmitting only the encrypted CW (Ecsprk (CW)) without including the EMM in the ECM, The ECM generation unit encrypts the CW received from the CW generation unit with the public key CSprk of the CAS server, generates the ECM using the encrypted CW (Ecsprk (CW)), and generates the generated ECM through the scrambler. Software-based mobile reception restriction system for improving the bandwidth, characterized in that for transmitting to the CAS client. According to claim 1, The subscriber information issuing system, It issues subscriber information (SID) for each CAS client, transfers the issued subscriber information (SID) to the CAS server through an SSL / TLS mechanism, encodes the subscriber information (SID), and encodes the encoded SID (TSID). And encrypting again with a password received from a subscriber, and then transmitting the encrypted TSID (Epsw) to the CAS client. The method of claim 1, wherein the CAS client, A message and packet receiver configured to receive the ECM and scrambled TS packets from the CAS server; A subscriber information storage unit for receiving and storing an encrypted TSID (Epsw (TSID)) from a subscriber information issuing system for issuing subscriber information (SID) for each CAS client in advance; Decrypt the TSID obtained by decrypting the encrypted TSID (Epsw (TSID)) with a password inputted from a subscriber who is allowed to access through a login module, and the TSID received from the message and packet receiving unit, respectively. A subscriber information decryption and verification unit for comparing and matching two subscriber information (SID); A security rule generator for generating a subscriber key (USK) using subscriber information (SID) verified by the subscriber information decryption and verification unit; An EMM decryption and analysis unit for decrypting an encrypted public key (Eusk (CSpuk)) included in the EMM received from the message and packet receiver with the subscriber key (USK) received from the security rule generator; An ECM decryption and analysis unit for decrypting an encrypted CW (Ecsprk (CW)) included in the ECM received from the message and packet receiver with a public key (CSpuk) received from the EMM decryption and analysis unit; And a descrambler for descrambling the scrambled TS packet received through the message and packet receiver to a CW received from the ECM decoding and analysis unit. The method of claim 8, wherein the CAS client, A public key storage unit for receiving and storing an encrypted public key (Eusk (CSpuk)) from the EMM decryption and analysis unit; Decrypt the encrypted public key (Eusk (CSpuk)) received from the public key storage unit with the subscriber key (USK) received from the security rule generator, and decrypt and analyze the ECM decrypted public key (CSpuk). It further comprises a public key decryption unit for passing to the negative, The EMM decryption and analysis unit encrypts the public key (CSpuk) decrypted by the EMM decryption and analysis unit again with the subscriber key (USK) received from the security rule generator, and then encrypts the encrypted public key (Eusk (CSpuk)). ) Is stored in the public key storage unit. The method of claim 8, wherein the message and packet receiving unit, The scrambled TS packet received from the CAS server is delivered to the descrambler, and if the ECM is analyzed and the EMM is included in the ECM, after extracting the EMM from the ECM, the ECM decrypted the ECM extracted from the EMM. And extracting a TSID from the EMM by analyzing the EMM extracted from the ECM, and transferring the extracted TSID to the subscriber information decryption and verification unit, and extracting the TSID to the EMM decryption and analysis unit. Software-based mobile reception restriction system for improving the bandwidth, characterized in that for transmitting. The method of claim 8, wherein the subscriber information decryption and verification unit, A subscriber information decryption module which receives an encrypted TSID (Epsw (TSID)) and a password from the subscriber information storage unit, and decrypts the encrypted TSID (Epsw (TSID)) with the password to obtain a TSID; Decode the TSID received from the subscriber information decoding module through a decoding module to obtain an SID, decode the TSID received from the message and packet receiver through the decoding module to obtain an SID, and then obtain the SID. Comparing one or two SIDs and verifying that they match, if the two SIDs match, a verification module for transmitting the SID to the security rule generation unit comprises a software-based mobile reception restriction for bandwidth enhancement. system. The method of claim 8, wherein the ECM includes at least two EMMs for transmission. The message and packet receiver extracts at least two EMMs from the ECM, extracts TSIDs from each extracted EMM, and transfers the extracted TSIDs to the subscriber information decryption and verification unit. The subscriber information decryption and verification unit decrypts at least two or more TSIDs received from the message and packet receivers, respectively, to obtain at least two or more subscriber information (SIDs), and encrypts the encrypted TSIDs received from the subscriber information storage unit. Subscriber information (SID) obtained by decrypting the TSID obtained by decrypting Epsw (TSID)) is compared with the at least two subscriber information (SID), respectively, and the matching subscriber information (SID) is matched to the security rule generator. Software-based mobile reception restriction system for improving the bandwidth, characterized in that for transmitting. The method of claim 8, wherein when the ECM includes only an encrypted CW (Ecsprk (CW)) without transmitting an EMM, The message and packet receiving unit delivers the ECM to the ECM decoding and analyzing unit, The subscriber information decryption and verification unit decrypts the encrypted TSID (Epsw (TSID)) received from the subscriber information storage unit with a password received from a subscriber who is allowed to access, obtains a TSID, and returns the obtained TSID to a decryption module. After decrypting and obtaining subscriber information (SID), the subscriber information (SID) is transmitted to the security rule generator. The security rule generator generates a subscriber key (USK) using the subscriber information (SID), delivers the generated subscriber key (USK) to a public key decryption unit, The public key decryption unit decrypts the encrypted public key (Eusk (CSpuk)) stored in the public key storage unit with the subscriber key (USK), and transfers the decrypted public key (CSpuk) to the ECM decryption and analysis unit. , The ECM decryption and analysis unit decrypts the encrypted CW (Ecsprk (CW)) included in the ECM received from the message and packet receiver with the public key (CSpuk) received from the public key decryption unit, and then decrypts the decrypted CW. Software-based mobile reception restriction system for improving the bandwidth, characterized in that for transmitting to the descrambler. A CAS DB storing subscriber information (SID: Subscriber ID) issued for each Conditional Access System (CAS) client from the subscriber information issuing system; A security rule generator for generating a subscriber key (USK) using the subscriber information (SID) received from the CAS DB; The subscriber key USK and the subscriber information SID are received together from the security rule generator, the public key CSpuk of the CAS server is encrypted using the subscriber key USK, and the subscriber information SID is encoded. An EMM generating unit for generating an Entitlement Management Message (EMM) using an encrypted public key (Eusk (CSpuk)) and encoded subscriber information (TSID); A CW generator for generating CW (Control Word) using an arbitrary random number method; Encrypt the CW received from the CW generation unit with the private key (CSprk) of the CAS server, and encrypt an Entitlement Control Message (ECM) using the encrypted CW (Ecsprk (CW)) and the EMM received from the EMM generation unit. An ECM generator for generating; And a scrambler that concatenates the scrambled TS packet and the ECM received from the ECM generator and transmits the scrambled TS packet to the CAS client to the CAS client. A message and packet receiver configured to receive an Entitlement Control Message (ECM) and scrambled Transport Stream (TS) packets from a Conditional Access System (CAS) server; A subscriber information storage unit for receiving and storing an encrypted TSID (Epsw (TSID)) from a subscriber information issuing system for issuing subscriber information (SID) for each CAS client in advance; Decrypt the TSID obtained by decrypting the encrypted TSID (Epsw (TSID)) with a password inputted from a subscriber who is allowed to access through a login module, and the TSID received from the message and packet receiving unit, respectively. A subscriber information decryption and verification unit for comparing and matching two subscriber information (SID); A security rule generator for generating a subscriber key (USK) using subscriber information (SID) verified by the subscriber information decryption and verification unit; EMM decryption and analysis for decrypting the encrypted public key (Eusk (CSpuk)) included in the Entitlement Management Message (EMM) received from the message and packet receiver with the subscriber key (USK) received from the security rule generator Wealth; An ECM decryption and analysis unit for decrypting an encrypted CW (Ecsprk (CW)) included in the ECM received from the message and packet receiver with a public key (CSpuk) received from the EMM decryption and analysis unit; And a descrambler for descrambling the scrambled TS packet received through the message and packet receiver to a CW received from the ECM decryption and analysis unit.

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