JP2007081597A - System for authenticating multicast stream by cipher key distribution via authentication server - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for authenticating multicast streams by cipher key distribution via an authentication server. <P>SOLUTION: The system authenticates the multicast stream by the cipher key distribution, and comprises a distributing device 100 for encrypting distribution data for distribution by using a multicast system; a reproduction terminal 120 for receiving and decoding the data distributed from the distributing device 100 to reproduce the distributed data; and an authenticating device 110 that is provided independently of the distributing device 100, and authenticates whether the reproduction terminal 120 has a right for reading the distributed data. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multicast stream authentication system using cryptographic key distribution via an authentication server.

  The packet distribution method in the IP network specifies unicast distribution in which data is transmitted to a specific partner by specifying a single address, broadcast distribution in which data is transmitted to a large number of unspecified parties, and multiple partners are specified. Multicast distribution that transmits the same data.

  Conventionally, when broadcasting delivery to a plurality of terminals, unicast delivery has been performed in which a plurality of identical packets are delivered simultaneously end-to-end within the same segment.

  However, the unicast distribution has a problem that when the number of recipients increases, the number of packets must be transmitted as many as the number of recipients, so that the line is congested and the line bandwidth usage efficiency deteriorates.

  In broadcast distribution, the same packet is transmitted to all terminals of the network, so that there is a problem that the use efficiency of the line bandwidth is poor.

  In contrast to these distribution methods, multicast distribution distributes packet data only to multiple partners who are subscribed to a specific group, so it does not send useless packets and improves line bandwidth usage efficiency. It becomes possible. In recent years, many network devices compatible with multicast distribution have started to appear, and multicast distribution is being widely used in the field of video / audio distribution using an IP network (see Patent Document 1).

JP 2004-363897 A

  However, for distribution data such as video and audio distributed in multicast, know the multicast group address of the distribution destination and the port number of the distribution data in some way, and use the multicast group on the playback terminal without viewing authority. If an address and a port number are set, even a terminal without browsing authority can receive the packet and browse the distribution data. For this reason, there is a problem that it is difficult to permit reproduction of distribution data only on a specific terminal.

  Therefore, the present invention has been made in view of such problems, and an object of the present invention is to provide a new and improved multicast stream authentication system using cryptographic key distribution via an authentication server. is there.

  In order to solve the above-described problem, according to an aspect of the present invention, there is provided a multicast stream authentication system using cryptographic key distribution, a distribution device that encrypts and distributes distribution data using a multicast method, and a distribution device A reproduction terminal that receives and decrypts distribution data distributed from and reproduces the distribution data, and an authentication device that is provided independently of the distribution device and authenticates whether the reproduction terminal has an authority to view the distribution data The distribution device includes a key distribution unit that receives the public key of the authentication device, an encryption / decryption key generation unit that generates a common key for encrypting and decrypting the distribution data, and the distribution data as the common key. The authentication device includes a key database in which the common key generated by the encryption / decryption key generation unit of the distribution device is registered, and the public key of the distribution device. A key receiving and distributing unit that receives the public key of the reproduction terminal, an authentication unit that registers the public key of the reproduction terminal and confirms whether the reproduction terminal has the authority to view distribution data, and the reproduction terminal receives the distribution data And a collection unit that collects the distribution data transmission request packet, and the reproduction terminal is encrypted with the public key of the reproduction terminal on the authentication device and distributed from the authentication server. A decryption unit that decrypts the common key; a decryption unit that decrypts the distribution data using the common key; and a transmission unit that transmits a distribution data transmission request packet to receive the distribution data. A multicast stream authentication system using cryptographic key distribution is provided.

  According to such a configuration, a common key for decrypting the distribution data can be given from the authentication server only to the playback terminal having the authority to view the distribution data distributed from the distribution device. Therefore, even if it is possible to know the multicast group address of the distribution destination of the distribution data and the port number of the distribution data by a certain method, the distribution data can be reproduced if there is no common key for decrypting the distribution data. Because it is not possible, wiretapping of distribution data can be prevented.

  The distribution device may include an encoder, and the playback terminal may include a decoder. According to such a configuration, the encoder encodes data serving as the basis of the distribution data, and the decoder decodes the distribution data encoded by the encoder. As a result, the capacity of distribution data can be reduced.

  The authentication unit may store device identification information of the reproduction terminal, a public key distributed from the reproduction terminal, and information of a reproducible multicast group address, and the device identification information may be a MAC address. Good. According to such a configuration, the authentication unit authenticates whether the reproduction terminal has browsing authority using the device identification information described in the distribution data transmission request packet transmitted by the reproduction terminal. As a result, it is possible to prevent browsing of the distribution data of the playback terminal without the viewing authority.

  The key database may store multicast group addresses and the common key information. According to this configuration, the key database distributes the common key to the playback terminal that is authenticated as having the browsing authority by the authentication unit. As a result, it is possible to distribute the common key for decrypting the distribution data only to the reproduction terminal that is authenticated as having the viewing authority.

  The playback terminal may be separately connected to an output device that outputs distribution data, and the output device may be integrated with the playback terminal.

  The delivery data transmission request packet may be a join packet that is a packet for joining a multicast group of the Internet Group Management Protocol (IGMP), which is a multicast protocol. According to this configuration, even if the distribution data transmission request packet is an IGMP join packet, the same operation can be obtained. Therefore, even when an IGMP join packet is used, the authentication unit can authenticate the playback terminal.

  In order to solve the above-described problem, according to another aspect of the present invention, authentication for authenticating whether a reproduction terminal has reproduction authority for distribution data distributed from a distribution apparatus by using a multicast scheme, using a key authentication scheme. A key database for registering a common key for decrypting distribution data generated by the distribution device, and a key receiving and distribution unit for receiving a public key transmitted from the distribution device and a public key transmitted from a playback terminal. , Registering the public key transmitted from the playback terminal, authenticating whether the playback terminal has the authority to view the distribution data, and when the playback terminal sends out the distribution data transmission request packet, An authentication apparatus is provided that includes a collection unit that collects the data.

  According to such a configuration, only the playback terminal having the authority to view the distribution data distributed from the distribution device can be given a common key for decrypting the distribution data from the authentication server. Therefore, since the terminal having no viewing authority cannot receive the common key, it is possible to prevent the distribution data from being reproduced on the reproducing terminal having no viewing authority.

  The key database may store information on a multicast group address and a public key corresponding to the multicast group address. According to this configuration, the key database distributes the common key to the playback terminal that is authenticated as having the browsing authority by the authentication unit. As a result, it is possible to distribute the common key for decrypting the distribution data only to the reproduction terminal that is authenticated as having the viewing authority.

  The collection unit may collect the delivery data transmission request packet in a promiscuous mode.

  The authentication unit may store device identification information of the reproduction terminal, a public key distributed from the reproduction terminal, and information of a reproducible multicast group address, and the device identification information is a MAC address. May be. According to such a configuration, the authentication unit authenticates whether the reproduction terminal has browsing authority using the device identification information described in the distribution data transmission request packet transmitted by the reproduction terminal. As a result, it is possible to prevent browsing of the distribution data of the playback terminal without the viewing authority.

  When the device identification information and the multicast group address described in the delivery data transmission request packet are registered in the authentication unit, the authentication unit sends the common key corresponding to the multicast group address from the playback terminal. It may be encrypted with the distributed public key and given to the playback terminal.

  In order to solve the above-described problem, according to still another aspect of the present invention, there is provided a distribution device that distributes distribution data using a multicast method and authenticates the viewing authority of the distribution data with an authentication device, wherein the distribution data An encryption / decryption key generation unit for generating a common key for performing encryption and decryption of the data, and a public key transmitted from the authentication device, and encrypting the common key with the public key transmitted from the authentication device A distribution device is provided, which includes a key distribution unit for granting to the user and an encryption unit for encrypting distribution data with a common key.

  According to this configuration, the distribution data is encrypted on the distribution device, and the authentication device can separately store the common key necessary for decrypting the encrypted distribution data. Therefore, it is necessary to obtain a common key from the authentication device for reproduction of distribution data, and reproduction of distribution data on a terminal without viewing authority can be prevented by performing appropriate authentication with the authentication device.

  The distribution device may include an encoder. According to this configuration, the data that is the basis of the distribution data is encoded. As a result, the capacity of distribution data can be reduced.

  The distribution apparatus may generate a common key for the encryption / decryption key generation unit to encrypt and decrypt distribution data after the encoder starts encoding.

  As described above, according to the present invention, the distribution data distributed from the distribution device can be reproduced without the viewing authority by distributing the key necessary for the decryption from the authentication server only to the reproduction terminal having the viewing authority. It is possible to provide a multicast stream authentication system using cryptographic key distribution that can be prevented from being reproduced on a terminal.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a configuration diagram of a multicast stream authentication system by encryption key distribution via an authentication server according to the present embodiment.

  As shown in FIG. 1, the multicast stream authentication system using cryptographic key distribution via the authentication server according to the present embodiment includes a distribution device 100, a router 150, a switching hub 160, a reproduction terminal 120, and a reproduction terminal 120. The authentication server 110 is an authentication device that confirms whether or not the user has viewing authority for the video / audio source 130. The distribution apparatus 100 encodes the video / audio source 130 to generate a video / audio stream serving as distribution data, encrypts the generated video / audio stream, and distributes the encrypted distribution data to the IP network 140. To do. The playback terminal 120 decodes the encrypted video / audio stream, decodes the video / audio stream, and plays back the video / audio source 130.

Distribution device 100, the encryption and decryption key generating unit 101 for creating the common key K _m, which is necessary for encoding and decoding of video and audio streams, encrypts the common key K _m, key distribution to be distributed to the authentication server 110 and parts 103, using the common key K _m, the stream encryption unit 105 is an encryption unit that encrypts the video and audio streams, a network interface 107 connected to IP network 140, video and audio source And an encoder 109 that encodes 130 to generate a video / audio stream. Here, the subscript _m of the common key _Km is added as the meaning of the master key.

  The authentication server 110 distributes and receives keys between the key database 111 that registers the encryption / decryption key distributed from the key distribution unit 103 of the distribution apparatus 100, the distribution apparatus 100, and the playback terminal 120. A key receiving / delivering unit 113 to perform, an authentication unit 115 for checking whether or not the playback terminal 120 has viewing authority, a network interface 117 connected to an external network, and a CPU 119 for controlling the operation of each unit of the authentication server 110. . At least one authentication server 110 is installed per segment.

The playback terminal 120 is distributed from the authentication server 110, decrypts the encrypted video / audio stream, decrypts the encrypted decryption key, and decrypts the common decrypted by the key decryption unit 121. Using the key K _m , a stream decoding unit 123 that decodes the encrypted video / audio stream, a network interface 125 connected to the external network, and a decoder 127 that decodes the decoded video / audio stream And a CPU 129 that controls the operation of each unit of the playback terminal 120. Although FIG. 1 shows a case where there is one playback terminal 120, the number of playback terminals 120 may be two or more.

  The playback terminal 120 may be separately connected with a video / audio output device 170 that outputs the decoded video / audio stream. The video / audio output device 170 generally refers to a device that outputs video and audio, such as a monitor and a speaker. Although FIG. 1 shows a case where one video / audio output device 170 is connected to the playback terminal 120, two or more video / audio output devices 170 may be connected to the playback terminal 120. Further, the video / audio output device 170 may have a structure integrated with the playback terminal 120.

  The CPU 129 of the playback terminal 120 includes a role of a sending unit that sends a delivery data transmission request packet to the delivery device 100. Further, the CPU 119 of the authentication server 110 includes a role of a collection unit that collects distribution data transmission request packets.

  Next, an eavesdropping countermeasure method using a multicast stream authentication system using cryptographic key distribution via an authentication server according to the present embodiment will be described.

  FIG. 2 is a flowchart of an eavesdropping countermeasure method using a multicast stream authentication system using cryptographic key distribution via an authentication server according to the present embodiment.

The wiretapping countermeasure method using the multicast stream authentication system by encryption key distribution via the authentication server according to the present embodiment registers the public key k _p of the authentication server 110 in the distribution apparatus 100 in advance, and the public key of the playback terminal 120. _Kp and the MAC address, which is the device identification information of all playback terminals 120 having browsing authority, are registered in advance in the authentication unit 115 of the authentication server 110. The MAC address is a hardware address that is set to identify a host in the network, and one MAC address is a unique number that is unique in the world. Here, p subscript of public key _{k p} and _{K p} are denoted as the meaning of the public (the public).

  Further, all multicast group addresses to be distributed by multicast are registered in advance in the key database 111 of the authentication server 110.

When the video / audio source 130 is input to the distribution apparatus 100, the encoder 109 starts encoding of the video / audio source 130 and generates a video / audio stream (S100). The subsequent the encoding is started, the encryption and decryption key generating unit 101 generates a common key K _m for performing encryption and decryption of image and sound streams (S110).

Common key _{K m} thus generated is encrypted with the public key _{k p} of the authentication server 110 (S120). Common key _{K m,} which is encrypted, is transmitted to the authentication server 110 by the key delivery unit 103 (S130).

The encrypted common key K _m is decrypted with the secret key k _s of the authentication server 110 by the key receiving / delivery unit 113 of the authentication server 110 (S140) and stored in the key database 111 (S150). Here, the subscript _s of the secret key k _s is attached as the meaning of secret (secret).

The encoded video / audio source 130 is encrypted by the stream encryption unit 105 (S160). During encryption, using the common key K _m for encryption and decryption key generating unit 101 has generated. When the encryption of the encoded video / audio source 130 is completed, the distribution apparatus 100 distributes it to the IP network 140 through the network interface 107 (S170).

  When the user having the playback terminal 120 is to receive and play the distributed video / audio stream, he / she operates the playback terminal 120 and requests the distribution apparatus 100 to transmit distribution data (S180). The sending unit provided in the CPU 129 of the playback terminal 120 sends a delivery data transmission request packet in which the multicast group address to be played back and the MAC address of the playback terminal 120 are described to the delivery device 100. This distribution data transmission request packet may be a join packet of IGMP (Internet Group Management Protocol) which is a multicast protocol.

  When the distribution data transmission request packet is transmitted over the network, the collection unit provided in the CPU 119 of the authentication server 110 collects the distribution data request packet (S190). When the collection unit collects the distribution data transmission request packet, the collection data transmission request packet may be collected in a promiscuous mode in which all packets flowing through the network can be received unconditionally.

  The authentication unit 115 reads the multicast group address described in the distribution data transmission request packet and the MAC address that is the device identification information of the playback terminal 120, and distributed data distributed from the multicast group address described in the distribution data transmission request packet It is determined whether or not the playback terminal 120 has the viewing authority (S200).

  When determining whether or not the user has the browsing authority, a reproduction terminal information table in the authentication unit 115 as shown in FIG. 3 is referred to. In this table, the MAC address that is the device identification information of the playback terminal 120, the public key of the playback terminal 120, and the multicast group address that can be played back by the playback terminal 120 are registered.

When the reproduction terminal information table is searched with the MAC address described in the distribution data transmission request packet and the MAC address does not exist in the reproduction terminal information table, or even if the MAC address is registered in the reproduction terminal information table, the distribution data If the record of the multicast group address described in the transmission request packet does not exist, the reproduction terminal 120 assumes that there is no viewing authority, the authentication server 110 does not confer common key K _m to reproduction terminal 120.

On the other hand, if a record including both the MAC address and multicast group address of the playback terminal 120 described in the distribution data transmission request packet exists in the playback terminal information table, the playback terminal 120 is regarded as having viewing authority. The common key K _m is given to the playback terminal 120. A common key is searched from the multicast group address-key correspondence table registered in the key database as shown in FIG. 4, and the common key corresponding to the multicast group address described in the distribution data transmission request packet is sent to the playback terminal 120. It becomes a common key to be awarded. When granting the common key _{K m,} using the public key _{K p} of the reproduction terminal 120 that has been registered in advance in the authentication unit 115, encrypts the common key _{K m} (S210). The common key _{K m} after encrypting distributes the common key _{K m} in the reproduction terminal 120 (S220).

  To explain using the playback terminal information table shown in FIG. 3, the MAC address of the playback terminal that sent the delivery data transmission request packet is 00-01-02-03-04-06-07, and the delivery data transmission request packet Is 23.192.0.0, the information on the MAC address and multicast group address is registered in the playback terminal information table. I reckon.

  On the other hand, the MAC address of the playback terminal that has transmitted the distribution data transmission request packet is 00-01-02-03-04-06-07, and the multicast group address described in the distribution data transmission request packet is 239.192.0. In the case of 32, since the information of the MAC address and the multicast group address is registered in the reproduction terminal information table, it is considered that this reproduction terminal does not have the browsing authority.

  If the MAC address of the playback terminal that sent the distribution data transmission request packet is 00-01-02-03-04-06-06, this MAC address itself is not registered in the playback terminal information table. It is assumed that the playback terminal does not have viewing authority.

Reproduction terminal 120 receives the common key _{K m} encrypted, the key decryption unit 121, decrypts the common key _{K m} by using the secret key _{K s} of the reproduction terminal 120 (S230). Here, the subscript _s of the secret key K _s is attached as the meaning of secret (secret) like the secret key k _s .

Decoding the common key K _m, the stream decoding unit 123 decodes the distribution data by using the common key K _m (S240), decodes the video and audio stream by the decoder 127 extracts the video and audio data ( S250).

  The extracted video / audio data is output from the output device 170 (S260). By outputting the video / audio data from the output device 170, the user can view the video / audio data.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  The present invention can be applied to a multicast stream authentication system using encryption key distribution via an authentication server.

It is explanatory drawing which shows embodiment of this invention. 3 is a flowchart of an embodiment of the present invention. It is a data structure of the reproduction | regeneration terminal information table in the authentication part of embodiment of this invention. It is a data structure in the key database of the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Distribution apparatus 101 Encryption / decryption key generation part 103 Key distribution part 105 Stream encryption part 107 Network interface 109 Encoder 110 Authentication server 111 Key database 113 Key receiving / delivery part 115 Authentication part 117 Network interface 120 Playback terminal 121 Key decryption part 123 Stream Decoding Unit 125 Network Interface 127 Decoder 130 Video / Audio Source 140 IP Network 150 Router 160 Switching Hub 170 Output Device K _m Video / Audio Stream Encryption / Decryption Common Key k _p Authentication Server 110 Public Key k _s Authentication Server 110 the secret key of the public key K _s reproduction terminal 120 of the secret key K _p reproduction terminal 120 of

Claims (20)

A multicast stream authentication system with cryptographic key distribution:
A distribution device that encrypts and distributes distribution data using a multicast method;
A reproduction terminal that receives and decodes distribution data distributed from the distribution device and reproduces the distribution data;
An authentication device that is provided independently of the distribution device and authenticates whether the reproduction terminal has the right to view the distribution data;
Including
The distribution device includes:
A key distribution unit that receives a public key transmitted from the authentication device;
An encryption / decryption key generation unit for generating a common key for encrypting and decrypting the distribution data;
An encryption unit for encrypting the distribution data with the common key;
Including
The authentication device is:
A key database in which a common key generated by the encryption / decryption key generation unit of the distribution device is registered;
A key receiving and distributing unit that receives the public key of the distribution device and the public key of the playback terminal;
An authentication unit for registering the public key of the reproduction terminal and confirming whether the reproduction terminal has an authority to view the distribution data;
A collection unit that collects the distribution data transmission request packet when the reproduction terminal transmits the distribution data transmission request packet to receive the distribution data;
Including
The playback terminal is
A decryption unit that decrypts the common key that is encrypted with the public key of the playback terminal and distributed from the authentication server in the authentication device;
A decryption unit for decrypting the distribution data using the common key;
A sending unit for sending a delivery data transmission request packet to receive the delivery data;
A multicast stream authentication system using cryptographic key distribution, comprising:   2. The multicast stream authentication system according to claim 1, wherein the distribution device includes an encoder that encodes data serving as a basis of the distribution data.   3. The multicast stream authentication system according to claim 2, wherein the reproduction terminal includes a decoder that decodes the distribution data encoded by the encoder.   The said authentication part stores the apparatus identification information of the said reproduction | regeneration terminal, the public key of the said reproduction | regeneration terminal, and the information of the multicast group address which can be reproduced | regenerated, The one in any one of Claims 1-3 characterized by the above-mentioned. Multicast stream authentication system using cryptographic key distribution.   5. The multicast stream authentication system according to claim 4, wherein the device identification information is a MAC address.   6. The multicast stream authentication system according to claim 1, wherein the key database stores a multicast group address and information on the common key.   7. The multicast stream authentication system according to claim 1, wherein an output device for outputting distribution data is separately connected to the reproduction terminal.   The multicast stream authentication system according to claim 7, wherein the output device is integrated with the playback terminal.   9. The multicast stream authentication system according to claim 1, wherein the distribution data transmission request packet is a join packet of an Internet group management protocol which is a multicast protocol. An authentication device that authenticates, using a key authentication method, whether a reproduction terminal has the authority to reproduce distribution data distributed from a distribution device using a multicast method:
A key database for registering a common key for decrypting the distribution data generated by the distribution device;
A key receiving and distributing unit that receives a public key transmitted from the distribution device and a public key transmitted from the playback terminal;
An authentication unit that registers a public key transmitted from the playback terminal and authenticates whether the playback terminal has an authority to view the distribution data;
A collection unit that collects the distribution data transmission request packet when the reproduction terminal transmits the distribution data transmission request packet;
An authentication device comprising:   11. The authentication apparatus according to claim 10, wherein the key database stores information on a multicast group address and a public key corresponding to the multicast group address.   The authentication device according to claim 10 or 11, wherein the collection unit collects the distribution data transmission request packet in a promiscuous mode.   The said authentication part stores the apparatus identification information of the said reproduction | regeneration terminal, the public key of the said reproduction | regeneration terminal, and the information of the multicast group address which can be reproduced | regenerated, It is characterized by the above-mentioned. Authentication device.   When the device identification information and the multicast group address described in the distribution data transmission request packet are registered in the authentication unit, the authentication unit obtains the common key corresponding to the multicast group address of the playback terminal. 14. The authentication device according to claim 13, wherein the authentication device is encrypted with a public key and is given to the playback terminal.   The authentication device according to claim 13, wherein the device identification information is a MAC address. A distribution apparatus that distributes distribution data using a multicast method and authenticates the viewing authority of the distribution data with an authentication apparatus:
An encryption / decryption key generation unit for generating a common key for encrypting and decrypting the distribution data;
A key distribution unit that receives a public key transmitted from the authentication device, encrypts the common key with a public key transmitted from the authentication device, and grants the same to the authentication device;
An encryption unit for encrypting the distribution data with the common key;
A distribution device characterized by including:   The distribution apparatus according to claim 16, wherein the distribution apparatus includes an encoder that encodes data serving as a basis of the distribution data.   18. The distribution apparatus according to claim 17, wherein the encryption / decryption key generation unit generates a common key for encrypting and decrypting distribution data after the start of encoding by the encoder.   A computer program for causing a computer to function as the authentication device according to any one of claims 10 to 15. A computer program for causing a computer to function as the distribution device according to any one of claims 16 to 18.

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