Patent Application
20050232593
1. Field of the Invention
The present invention relates to a recording/reproduction technique, and particularly to a recording/reproduction device for encrypting and inputting/outputting data which is to be kept secret, and a method thereof.
2. Description of the Related Art
In recent years, handling of audio contents and video contents in the form of digital contents is becoming wide-spread. For example, terrestrial digital broadcasting has been introduced. Digital contents enable recording without deterioration in image quality or sound quality, thereby markedly improving ease-of-use for the user. However, such a technique which allows the user to make a copy without restriction leads to serious copyright infringement concerns. Accordingly, development of a device for recording/reproducing digital contents must be made giving sufficient consideration to copyright protection.
As a digital-contents reproduction technique developed giving consideration to copyright protection, a technique has been proposed wherein a decryption key used for encrypted contents is encrypted based upon the public key cryptosystem for input/output (e.g., see International Publication WO 01-043339). Decryption of the data encrypted based upon the public key cryptosystem requires a considerable amount of calculation, meaning that a great amount of time is necessary for decryption. Accordingly, the data-reproduction device disclosed in International Publication WO 01-043339 has an arrangement for performing authentication processing based upon the public key cryptosystem prior to reproduction, thereby realizing smooth reproduction.
While the data-reproduction device disclosed in International Publication WO 01-043339 has an arrangement wherein encrypted contents data is decrypted using a license key received from a single memory card at the time of reproduction, the present inventors have proposed an arrangement including multiple input/output paths for confidential data in their development of a device having recording and reproducing functions. Such a configuration requires a technique for effectively using the multiple input/output paths for inputting/outputting confidential data. Furthermore, such a device further having a function which allows the user to connect multiple storage media thereto leads to a more complicated situation.
The present invention has been made in view of the above problems, and accordingly, it is an object thereof to provide a technique for improving a device for encrypting the data which is to be kept secret for input/output while improving ease-of-use for the user.
A first aspect of the present invention relates to a recording/reproduction device. The recording/reproduction device comprises: a cryptography processing unit having a configuration which allows execution of a series of cryptography input/output processing actions in parallel, for encrypting the data which is to be kept secret, so as to be input/output to/from a storage medium for storing the data; and a management unit for managing the multiple cryptography input/output processing actions. In the event that the storage medium enters the state wherein the storage medium can be used, the management unit instructs the cryptography processing unit to execute session establishment processing including at least part of the series of cryptography input/output processing actions. Furthermore, reproduction session establishment processing for reading out the data, which is to be kept secret, from the storage medium is executed with higher priority than with recording session establishment processing for writing the data, which is to be kept secret, to the storage medium.
The data which is to be kept secret may be a contents key for decrypting encrypted digital contents, and so forth, for example. Examples of the cryptography input/output processing include: device authentication processing based upon the public key cryptosystem; transmission/reception processing for a temporary contents key for encrypting the data which is to be kept secret; transmission/reception processing for the encrypted data which is to be kept secret; and so forth. With the recording/reproduction device according to the present invention, at least part of a series of the aforementioned processing actions is executed beforehand. This allows the operation of the recording/reproduction device wherein, upon reception of the user instructions for recording or reproduction of the digital contents, the session establishment processing is skipped, and the subsequent cryptography input/output processing is executed, thereby reducing a delay from the user instructions up to the actual recording or reproduction. Furthermore, with the recording/reproduction device according to the present invention, the reproduction sessions are established with higher priority than with the recording sessions, thereby reducing a delay at the time of reproduction, and thereby improving the ease-of-use for the user.
The storage medium may be provided for a storage device removably mounted on the recording/reproduction device. Furthermore, the recording/reproduction device may have a configuration which allows the user to connect the multiple storage devices thereto, and further may include a detecting unit for detecting whether or not each of the multiple storage devices is connected to the recording/reproduction device. An arrangement may be made wherein, in the event that the detecting unit has detected the storage device connected to the recording/reproduction device, the management unit executes the aforementioned session establishment processing.
The session establishment processing may include processing wherein a device serving as a source of the data which is to be kept secret authenticates a device serving as a destination for the data which is to be kept secret. The authentication processing based upon the public key cryptosystem requires relatively long time. With the recording/reproduction device according to the present invention, the authentication processing is executed beforehand at the point that the storage device has entered the state wherein the storage device can be used, thereby reducing a delay at the time of reproduction.
An arrangement may be made wherein, in the event that the number of the storage media, which are connected to the recording/reproduction device and can be used, is smaller than the number of the cryptography input/output processing actions which the cryptography processing unit can execute in parallel, the management unit instructs the cryptography processing unit to execute the reproduction session establishment processing for allowing exchange of information between the recording/reproduction device and each storage medium which can be used, thereby enabling the cryptography processing unit to perform subsequent readout of the data, which is to be kept secret, from each storage medium without the reproduction session establishment processing until the storage medium enters the state wherein the storage medium cannot be used. The reproduction session for which the storage medium has been authenticated is maintained for maintaining the standby state for reproduction as long time as possible. This reduces delay at the time of reproduction.
An arrangement may be made wherein, in the event that the number of the storage media, which are connected to the recording/reproduction device and can be used, is equal to or greater than the number of the cryptography input/output processing actions which the cryptography processing unit can execute in parallel, at the time of writing the data which is to be kept secret, to the storage medium, the management unit instructs the cryptography processing unit to release one of the reproduction sessions thus established for the storage media, and to execute the cryptography input/output processing for writing the data which is to be kept secret, to the storage medium, following which the management unit instructs the cryptography processing unit to execute the reproduction session establishment processing again. With the recording/reproduction device according to the present invention, even in the event that there is the need to temporarily release the established reproduction session due to the shortage of the sessions which can be established in parallel at the time of recording of the program, upon completion of recording of the program, the reproduction session is established again instead of the recording session, whereby the recording/reproduction device enters the standby state for reproduction. This reduces delay at the time of reproduction.
A second aspect of the present invention relates to a recording/reproduction method. The recording/reproduction method wherein a series of cryptography input/output processing actions is executed in parallel for encrypting the data which is to be kept secret for input/output of the encrypted data to/from a storage medium for storing data comprises: a step wherein, in the event that the storage medium enters the state wherein the storage medium can be used, reproduction session establishment processing is executed, which includes at least part of the series of cryptography input/output processing actions for reading out the data which is to be kept secret, from the storage medium; a step wherein, in the event that there are any sessions which can be established in parallel for executing the series of cryptography input/output processing actions after execution of the reproduction session establishment processing for the storage media which can be used, recording session establishment processing is executed, which includes at least part of the series of cryptography input/output processing actions for writing the data which is to be kept secret, to the storage medium; a step for awaiting instructions for readout of the data which is to be kept secret, after execution of the reproduction session establishment processing; and a step wherein, in a case of reception of the instructions of readout of the data, the reproduction session establishment processing of the series of cryptography input/output processing is skipped, and the subsequent processing thereof is executed.
Note that any combination of the aforementioned components or any manifestation of the present invention realized by modification of method, system, recording medium, computer program, and so forth, is effective as an embodiment of the present invention.
Moreover, this summary of the invention does not necessarily describe all necessary features so that the invention may also be sub-combination of these described features.
The invention will now be described based on preferred embodiments which do not intend to limit the scope of the present invention but exemplify the invention. All of the features and the combinations thereof described in the embodiments are not necessarily essential to the invention.
At the time of recording the video/audio data of the received program (which will be simply referred to as “program data” hereafter) on the removable HDD unit 300, the recording/reproduction device 10 according to the present embodiment encrypts the program data using an encryption key prior to recording thereof, for copyright protection. The key used for encrypting the program data will be referred to as “contents key” hereafter. While the program data may be encrypted based upon any desired cryptosystem, description will be made in the present embodiment regarding an arrangement wherein the program data is encrypted based upon the symmetric key cryptosystem. With such a configuration, both the encryption and decryption of the program data are performed using the same key. The encryption of the program data has a low risk of being broken even in a case of data leakage, and accordingly, the encrypted program data is input/output according to ordinary read/write commands. On the other hand, the contents key required for reproducing the program data is highly secret data which requires security against leakage thereof, and accordingly, the contents key is input/output according to a special input/output protocol which gives high priority to security thereof (which will be referred to as “secure protocol” hereafter). With the present embodiment, a secure protocol based upon the public key cryptosystem is employed, and the program is recorded on a removable storage medium; accordingly, such an arrangement requires device-authentication processing prior to recording of the program, or reproducing thereof. With the secure protocol according to the present embodiment, authentication processing is performed using a device certificate. Upon confirmation of the validity of the certificate, the recording/reproduction device 10 establishes a session for transmission/reception of confidential data (which will be referred to as “secure session” hereafter).
At the time of reproducing the program data recorded on the removable HDD unit 300, the recording/reproduction device 10 needs to read out the contents key from the removable HDD unit 300 using the secure protocol. However, public key cryptosystem requires a relatively long time for decryption processing due to a large amount of calculation. Accordingly, an arrangement wherein the contents key is read out according to user instructions for reproduction leads to a delay of actual reproduction from the point in time that the user has made instructions for reproduction, resulting in a slower response than the user anticipates.
In order to solve the aforementioned problem, the recording/reproduction device 10 according to the present embodiment has a PKI secure module 200 which allows multiple processing sessions for input/output using the secure protocol in parallel. With such a configuration, these sessions are assigned to reproduction with high priority. Specifically, upon turning on the power supply, inserting the removable HDD unit 300 into the recording/reproduction device 10, and so forth, which allow the recording/reproduction device 10 to use the removable HDD unit 300, the recording/reproduction device 10 performs authentication processing in public key cryptosystem which requires relatively long processing time beforehand, so as to establish a session for reproduction with high priority, whereby the recording/reproduction device 10 enters the standby state awaiting instructions for reproduction from the user. This reduces the delay from the reception of the instructions for reproduction up to the actual reproduction.
First, description will be made regarding an arrangement according to the first embodiment, wherein the recording/reproduction device 10 has a configuration which allows the user to connect the single removable HDD unit 300 thereto, and performs processing with two secure sessions in parallel. Then description will be made regarding an arrangement according to a second embodiment, wherein the recording/reproduction device 10 has a configuration which allows the user to connect the two removable HDD units 300 thereto, and performs processing with two secure sessions in parallel. Subsequently, description will be made regarding an arrangement according to a third embodiment, wherein the recording/reproduction device 10 has a configuration which allows the user to connect the two removable HDD units 300 thereto, and performs processing with three secure sessions in parallel. Finally, description will be made regarding an arrangement according to a fourth embodiment, wherein the recording/reproduction device 10 has a configuration which allows the user to connect a desired predetermined number of removable HDD units 300 thereto, and performs processing with a desired predetermined number of secure sessions in parallel.
The recording/reproduction device 10 includes a remote-controller photoreception unit 100, a system controller 102, a display panel 104, an MPEG-TS decoder 106, a D/A converter 108, a display device 110, a removal HDD slot 112, a removal HDD insertion detecting unit 114, buffer memory 116, an antenna 118, a tuner 120, a transmission-line decoding unit 122, a TS separation/selection unit 124, a PKI secure module 200 which is an example of a cryptography processing unit.
The remote-controller photoreception unit 100 receives the light emitted from a remote controller (not shown) which allows the user to input instructions to the recording/reproduction device 10, thereby acquiring the instructions from the user. The system controller 102 controls each component of the recording/reproduction device 10. The system controller 102 includes a session management unit 103 for management of establishment of a secure session, release thereof, and so forth, performed by the PKI secure module 200. Note that the session management unit 103 manages the multiple secure sessions with session IDs described later. The session management unit 103 may be included within the PKI secure module 200. The display panel 104 displays various kinds of control information. The MPEG-TS decoder 106 decodes MPEG-TS signals. The D/A converter 108 converts digital signals into analog signals. The display device 110 displays the program data which has been decoded and converted into analog signals.
The removable HDD slot 112 allows the user to connect the removable HDD unit 300 which is a storage medium for recording the program data, to the recording/reproduction device 10. The removal HDD insertion detecting unit 114 detects whether the removable HDD unit 300 has been attached/detached to/from the removable HDD slot 112. The buffer memory 116 has functions serving as a storage area for storing data necessary for the operation of the recording/reproduction device 10, e.g., for temporarily storing MPEG/TS signals which have been separated and selected by the TS separation/selection unit 124.
The antenna 118 receives broadcasting signals subjected to digital conversion. The tuner 120 extracts the signals of the channel selected by the user, from the broadcasting signals received with the antenna 118, according to instructions from the system controller 102. The transmission-line decoding unit 122 decodes the signals extracted by the tuner 120, in the format of video/audio data coded in the MPEG2, and outputs the decoded data to the TS separation/selection unit 124. In the event that the program data is not stored in the removable HDD unit 300, the TS separation/selection unit 124 outputs MPEG transport stream signals to the MPEG-TS decoder 106. The MPEG-TS decoder 106 decodes the MPEG TS signals separated by the TS separation/selection unit 124. The D/A converter 108 converts the digital signals decoded by the MPEG-TS decoder 106, in the form of analog signals. The display device 110 displays the program data in the form of analog signals converted by the D/A converter 108. The PKI secure module 200 controls communication between the recording/reproduction device 10 and the removable HDD unit 300 using the secure protocol.
The PKI secure module 200 includes an input/output control unit 202, a certificate authentication unit 204, a temporary key holding unit 208, a certification holding unit 210, a key creating unit 212, a temporary license-data holding unit 214, a license-data creating unit 216, and a data encryption/decryption processing unit 218. Part or all of the aforementioned components may be realized by hardware means, e.g., by actions of a CPU, memory, and other LSIS, of a computer, and by software means, e.g., by actions of a program or the like, loaded to the memory. Here, the drawing shows a functional block configuration which is realized by cooperation of the hardware components and software components. It is needless to say that such a functional block configuration can be realized by hardware components alone, software components alone, or various combinations thereof, which can be readily conceived by those skilled in this art.
The input/output control unit 202 controls input/output of data between each component within the PKI secure module and an external component. The PKI secure module 200 stores confidential information such as a contents key, license data, and so forth, and accordingly, has a configuration which protects such confidential information from direct access from an external device, thereby preventing leakage of the confidential information. The certificate authentication unit 204 authenticates the validity of the certificate transmitted from the removable HDD unit 300. The temporary key holding unit 208 temporarily holds a key used in the secure session. The certificate holding unit 210 holds the certificate of the recording/reproduction device 10. The aforementioned certificate has been authenticated by an authentication authority, and includes an embedded public key of the recording/reproduction device 10. Note that the certificate is encrypted by the secret key of the authentication authority. The key creating unit 212 creates a key used in the secure session. The temporary license-data holding unit 214 temporarily holds the license data of the program received from the removable HDD unit 300 at the time of reproducing the program recorded on the removable HDD unit 300. The license-data creating unit 216 creates license data including the contents key and license information at the time of recording the program on the removable HDD unit 300. The data encryption/decryption processing unit 218 performs encryption processing for the data, and decryption processing for encrypted data.
The PKI secure module 200 according to the present embodiment manages the commands, encryption/decryption key, and so forth, using session IDs for distinguishing the sessions, thereby enabling parallel processing of the two secure sessions. Specifically, the session IDs are assigned to the input/output commands for allowing distinguishing of which session the command belongs to. Furthermore, at the time of storing the contents key, license data, and so forth, in the temporary key-holding unit 208 and the temporary license-data holding unit 214, such data is stored along with the corresponding session ID. The same can be said of an arrangement wherein the PKI secure module 200 performs processing with three or more sessions in parallel.
The ATA interface 302 accepts the command stipulated by the ATA (AT attachment) which is the standard of the ANSI (American National Standards Institute). Upon reception of the command issued by the recording/reproduction device 10, the command selector 304 determines whether the received command is an ordinary command or a secure-protocol command. In a case of an ordinary command, the command selector 304 transmits the command to the hard disk controller 306. On the other hand, in a case of a secure-protocol command, the command selector 304 transmits the command to the PKI secure module 330. Upon reception of the ordinary input/output command, the hard disk controller 306 writes/reads the data to/from the hard disk storage area 308. The PKI secure module 330 controls communication between the removable HDD unit 300 and the recording/reproduction device 10 using the secure protocol.
The PKI secure module 330 includes an input/output control unit 310, a certificate authentication unit 312, a temporary key holding unit 316, a certificate holding unit 318, a key creating unit 320, and a license-data storage area 322. The input/output control unit 310 controls input/output between each component within the PKI secure module 330 and an external component. The PKI secure module 330 stores confidential information such as the contents key, the license data, and so forth, and accordingly, has a configuration which protects such confidential information from direct access from an external device, thereby preventing leakage of the confidential information. The certificate authentication unit 312 authenticates the validity of the certificate transmitted from the recording/reproduction device 10. The temporary key holding unit 316 temporarily holds a key used in the secure session. The certificate holding unit 318 holds the certificate of the removable HDD unit 300. The certificate has been authenticated by the authentication authority, and includes an embedded public key of the removable HDD unit 300. Note that the certificate is encrypted with the secret key of the authentication authority. The key creating unit 320 creates a key used for the secure session. The license-data storage area 322 stores the license data including the contents key for reproducing the program recorded in the removable HDD unit 300.
First, the recording/reproduction device 10 acquires the program data from the digital broadcasting waves (S100). Specifically, the tuner 120 extracts the data of the channel selected by the user, from the broadcasting signals received with the antenna 118. Then, the transmission-line decoding unit 122 decodes the data, and the TS separation/selection unit 124 extracts the MPEG-TS signal, whereby the MPEG-TS signal is transmitted to the PKI secure module 200. The program transmitted to the PKI secure module 200 is transmitted to the data encryption/decryption processing unit 218 through the input/output control unit 202. The license-data creating unit 216 creates the contents key for encrypting the program data (S102). Furthermore, the license-data creating unit 216 extracts the license information such as the conditions for use, from the MPEG-TS signal, so as to create the license data of the program (S104). Let us say that the information regarding the conditions for use includes a digital-copy control descriptor (copy control information), a contents availability descriptor (temporary accumulation information), a parental rating descriptor (age-restriction information), and so forth. The license data includes the license information and the contents key.
The data encryption/decryption processing unit 218 encrypts the program data with the contents key (S106). The encrypted program data is transmitted to the removable HDD unit 300 through the input/output control unit 202 and the removable HDD slot 112. In the removable HDD unit 300, the encrypted program data is recorded in the hard disk storage area 308 through the ATA interface 302, the command selector 304, and the hard disk controller 306 (S108). During recording of the program (in a case of “No” in S110), the procedure for encrypting the program data (S106) and the procedure for writing the program data (S108) are repeated. Upon completion of the recording (in a case of “Yes” in Step S110), the recording/reproduction device 10 authenticates the removable HDD unit 300 (S112). In a case wherein determination has been made that the removable HDD unit 300 is valid, the recording/reproduction device 10 transmits the license data to the removable HDD unit 300 so as to be recorded on the removable HDD unit 300 (S114). Note that authentication of the removable HDD unit 300 and transmission of the license data are performed using the secure protocol based upon the public key cryptosystem. Detailed description will be made later regarding the authentication processing (S112) and the transmission processing for the license data (S114).
Finally, the application program updates the program management file 400 for managing the combinations of the encrypted program data and the license data (S116). An arrangement may be made wherein the recording/reproduction device 10 reads out and updates the program management file 400, following which the recording/reproduction device 10 rewrites the updated program management file 400 to the removable HDD unit 300. Furthermore, an arrangement may be made wherein the recording/reproduction device 10 transmits a command to the hard disk controller 306 or the like, so as to update the program management file 400.
While description has been made regarding an arrangement wherein the PKI secure module 200 of the recording/reproduction device 10 transmits the license data to the PKI secure module 330 of the removable HDD unit 300 following recording of the program data with reference to the drawing, the present invention is not restricted to such an arrangement wherein transmission of the license data is performed following recording of the program. Rather, an arrangement may be made wherein, following creation of the license data in S104, transmission of the license data is performed while transmitting the encrypted program data. Furthermore, an arrangement may be made wherein transmission of the encrypted program data is started following transmission of the license data. In this case, the encrypted program data is stored in the buffer memory 116 during transmission of the license data.
First, the removable HDD unit 300 authenticates the recording/reproduction device 10 (S132) in order to read out the license data-corresponding to the program which is to be reproduced. Upon successful authentication of the recording/reproduction device 10, the license data recorded in the license-data storage area 322 of the removable HDD unit 300 is transmitted to the PKI secure module 200 of the recording/reproduction device 10 (S134). Note that authentication of the recording/reproduction device 10 and transmission of the license data are performed using the secure protocol based upon the public key cryptosystem. Detailed description will be made later regarding the authentication processing (S132) and transmission processing for the license data (S134). The transmitted license data is temporarily held by the temporary license-data holding unit 214.
Next, the encrypted program data is read out from the hard disk storage area 308, and is transmitted to the recording/reproduction device 10 (S136). The data encryption/decryption processing unit 218 of the recording/reproduction device 10 decrypts the encrypted program data using the contents key included in the license data held by the temporary license-data holding unit 214. The decrypted program data is output to the display device 110 through the MPEG-TS decoder 106 and the D/A converter 108, whereby reproduction of the program data is performed (S138). During reproduction of the program (in a case of “No” in S140), the procedure for readout of the encrypted program data (S136) and the procedure for decryption/reproduction (S138) are repeated. Upon completion of reproduction of the program, or upon the user instructing the end of reproduction (in a case of “Yes” in S140), the processing ends.
First, detailed description will be made regarding the procedure wherein the recording/reproduction device 10 authenticates the removable HDD unit 300 so as to establish the recording session (S112). Upon start of the recording session for recording the license data on the removable HDD unit 300 (S200), first, the recording/reproduction device 10 makes a request to the removable HDD unit 300 for output of a certificate (S202). The removable HDD unit 300 outputs the certificate stored in the certificate holding unit 318 according to the aforementioned request (S204). The certificate authentication unit 20.4 of the recording/reproduction device 10 decrypts the encrypted certificate thus received, using the public key of the authentication authority embedded in the PKI secure module 200, whereby the validity of the certificate is checked (S206). Upon confirmation of the validity of the certificate, the key creating unit 212 creates a session key (S208), encrypts the session key using the public key of the removable HDD unit 300 embedded in the certificate, and outputs the encrypted session key (S210), as well as holding the session key in the temporary holding unit 208. The session key serves as a symmetric key temporarily valid in the recording session. The temporary key holding unit 316 of the removable HDD unit 300 decrypts the encrypted session key thus received, using the secret key of the removable HDD unit 300, and holds the session key (S212). At this point, the recording/reproduction device 10 and the removable HDD unit 300 share the session key.
Next, detailed description will be made regarding the procedure for transmission of the license data to the removable HDD unit 300 performed by the recording/reproduction device 10 (S114). The recording/reproduction device 10 makes a request to the removable HDD unit 300 for output of a challenge key (S250). The key creating unit 320 of the removable HDD unit 300 creates a challenge key according to the aforementioned request (S252). The removable HDD unit 300 encrypts the challenge key with the session key held by the temporary key holding unit 316 and outputs the challenge key thus encrypted (S254) while holding the challenge key in the temporary key holding unit 316. The temporary key holding unit 208 of the recording/reproduction device 10 decrypts the encrypted challenge key thus received, using the session key held by the temporary key holding unit 208, and holds the challenge key thus decrypted (S256). Next, the recording/reproduction device 10 reads out the license data which is to be transmitted to the removable HDD unit 300, from the temporary license-data holding unit 214, encrypts the license data with the challenge key, and outputs the encrypted license data (S258). The removable HDD unit 300 decrypts the encrypted license data thus received at the license-data storage area 322 thereof, using the challenge key held by the temporary key holding unit 316 (S260). Following the aforementioned procedure, this series of recording sessions ends (S262).
First, detailed description will be made regarding the procedure wherein the removable HDD unit 300 authenticates the recording/reproduction device 10 so as to establish the reproduction session (S132). Upon start of the reproduction session for readout of the license data from the removable HDD unit 300 (S300), first, the removable HDD unit 300 makes a request to the recording/reproduction device 10 for output of a certificate (S302). The recording/reproduction device 10 outputs the certificate stored in the certificate holding unit 210 according to the aforementioned request (S304). The certificate authentication unit 312 of the removable HDD unit 300 decrypts the encrypted certificate thus received, using the public key of the authentication authority embedded in the PKI secure module 330 so as to check the validity of the certificate (S306). In a case wherein the certificate is valid, the key creating unit 320 creates a session key (S308), and stores the session key in the temporary key holding unit 316. At the same time, the session key is encrypted with the public key of the recording/reproduction device 10 embedded in the certificate, and is output (S310). The session key serves as a symmetric key temporarily valid for the reproduction session. The temporary key holding unit 208 of the recording/reproduction device 10 decrypts the encrypted session key thus received, using the secret key of the recording/reproduction device 10, and holds the session key (S312). At this point, the removable HDD unit 300 and the recording/reproduction device 10 share the session key.
Next, detailed description will be made regarding the procedure for transmission of the license data to the recording/reproduction device 10 performed by the removable HDD unit 300 (S134). The removable HDD unit 300 makes a request to the recording/reproduction device 10 for output of a challenge key (S350). The key creating unit 212 of the recording/reproduction device 10 creates a challenge key according to the aforementioned request (S352). The recording/reproduction device 10 encrypts the challenge key with the session key held by the temporary key holding unit 208 and outputs the challenge key thus encrypted (S354) while holding the challenge key in the temporary key holding unit 208. The temporary key holding unit 316 of the removable HDD unit 300 decrypts the encrypted challenge key thus received, using the session key held by the temporary key holding unit 316, and holds the challenge key thus decrypted (S356). Next, the removable HDD unit 300 reads out the license data which is to be transmitted to the recording/reproduction device 10, from the license-data storage area 322, encrypts the license data with the challenge key, and outputs the encrypted license data (S358). The temporary license-data holding unit 214 of the recording/reproduction device 10 decrypts the encrypted license data thus received, using the challenge key held by the temporary key holding unit 208, (S360). Following the aforementioned procedure, this series of reproduction sessions ends (S362).
While the procedure for transmission/reception of the license data shown in
Description will be made regarding the recording procedure and the reproduction procedure for the program with the recording/reproduction device 10 according to the present invention with reference to
The recording/reproduction device 10 according to the present embodiment has a configuration which allows establishment of two secure sessions at the same time. Such a configuration allows the recording/reproduction device 10 to maintain the recording session and the reproduction session until the recording/reproduction device 10 cannot use the removable HDD unit 300. That is to say, there is no need to release the recording session and the reproduction session during the period of time wherein the recording/reproduction device 10 can use the removable HDD unit 300. Such a configuration allows the recording/reproduction device 10 to perform recording or reproduction processing according to second or more recording instructions or reproduction instructions without authentication processing (S112 in
(1) At the time that the power supply is on, no removable HDD unit 300 is detected.
(2) At the time that the power supply is on, the single removable HDD unit 300 is detected.
(3) At the time that the power supply is on, the two removable HDD units 300 are detected.
(4) As a result of insertion of the removable HDD unit 300, the total of one removable HDD unit 300 is detected.
(5) As a result of insertion of the removable HDD unit 300, the total of two removable HDD units 300 is detected.
(6) As a result of disconnection of the removable HDD unit 300, the total of one removable HDD unit 300 is detected.
(7) As a result of disconnection of the removable HDD unit 300, no removable HDD unit 300 is detected.
(8) The power supply is turned off.
Description will be made regarding the initializing routine executed by the session management unit 103 of the recording/reproduction device 10 at the time of transition between the states shown in
In a case of (1) or (8), the session management unit 103 executes no processing. In a case of (2) or (4), such an arrangement is the same as with the first embodiment, and accordingly, the session management unit 103 executes the initializing routine shown in
In a case of (3), the session management unit 103 establishes the reproduction sessions for each of the two removable HDD units 300a and 300b. In a case of (5), the recording/reproduction device 10 releases the recording session established for the removable HDD unit 300 which has been detected in the previous stage, so as to establish the reproduction session for the new removable HDD unit 300 detected in this stage. That is to say, the secure session is provided as a reproduction session regarding the new removable HDD unit 300, instead of the recording session for the other removable HDD unit 300. At the time of release of the secure session, the session management unit 103 instructs the temporary key holding units 208 and 316 to remove the temporary keys stored therein, as well as releasing the session ID assigned to the secure session which is to be released so as to allow the recording/reproduction device 10 to use the secure session. That is to say, the secure session is released, which allows the recording/reproduction device 10 to use the secure session for other purposes. In a case of (6), the recording/reproduction device 10 releases the session for the removable HDD unit 300 thus detached so as to establish the recording session for the remaining removable HDD unit 300. That is to say, the secure session is provided as a recoding session regarding the remaining removable HDD unit 300, instead of the reproduction session for the other removable HDD unit 300. In a case of (7), the recording/reproduction device 10 releases the session provided for the removable HDD unit 300 thus detached.
Description will be made in the present embodiment regarding an arrangement which allows the user to connect the two removable HDD units 300 to the recording/reproduction device 10, and performs processing with three secure sessions in parallel. The recording/reproduction device 10 according to the present embodiment has the same configuration as with the recording/reproduction device 10 according to the second embodiment shown in
Now, in a case of giving instructions to the removable HDD unit 300b for which the recording session has not been established, for recording of the program data (in a case of “Yes” in S608), there is the need to release one of the established sessions for establishing the necessary recording session. While the session management unit 103 may release any of these sessions, the reproduction sessions are preferably maintained with high priority. With the present embodiment, following recording of the program data on the removable HDD unit 300b (S610), the session management unit 103 releases the recording session for the removable HDD unit 300a (S612), and establishes the recording session for the removable HDD unit 300b instead of the recording session for the removable HDD unit 300a thus released (S614). This allows the recording/reproduction device 10 to record the license data on the removable HDD unit 300b while maintaining the reproduction sessions for each of the removable HDD units 300a and 300b, thereby reducing the delay at the time of reproduction. Upon completion of recording of the license data on the removable HDD unit 300b (S616), the session management unit 103 releases the recording session for the removable HDD unit 300b (S618), and establishes the recording session for the removable HDD unit 300a, i.e., the previous state (S620). While description has been made regarding an arrangement wherein, following completion of recording, the session state is returned to the previous state, an arrangement may be made wherein, following completion of recording, the session state is not returned to the previous state, but is kept in this state.
Description will be made in the present embodiment regarding the recording/reproduction device 10 which allows the user to connect a predetermined number of removable HDD units 300 thereto, and can perform processing with a predetermined number of secure sessions in parallel. With the present embodiment, in a case wherein the number of the removable HDD units 300 which can be used is smaller than the number of the sessions which can be used, the session management unit 103 provides the reproduction sessions for all of the removable HDD units 300, and assigns the remaining secure sessions as the recording sessions. Upon the recording/reproduction device 10 making a recording request to the removable HDD unit 300 for which the recording session has not been established, the session management unit 103 handles such a situation by releasing one of the recording sessions and establishing the necessary recording session instead of the recording session thus released in an appropriate manner following the procedure shown in
On the other hand, in a case wherein the number of the removable HDD units 300 which can be used is the same as the number of the sessions which can be used, the session management unit 103 establishes the reproduction sessions for all of the removable HDD units 300. Upon the recording/reproduction device 10 making a recording request to one of the removable HDD units 300, the session management unit 103 releases the reproduction session established for one of the removable HDD units 300, and establishes the recording session for the removable HDD unit 300 on which the program data is to be recorded. The session management unit 103 may release the reproduction session for the removable HDD unit 300 on which the program data is to be recorded. Furthermore, the session management unit 103 may release the reproduction session for the removable HDD unit 300 other than the removable HDD unit 300 on which the program data is to be recorded. The session management unit 103 may determine the removable HDD unit 300 corresponding to the reproduction session which is to be released, based upon the storage capacity, the remaining available storage, the number of the recorded programs, the frequency of reproduction, and so forth, regarding each removable HDD unit 300. Upon completion of recording of the program, the session management unit 103 releases the recording session, and establishes the reproduction session as in the previous state. In a case of detection of a new removable HDD unit 300 which can be used, the session management unit 103 establishes the reproduction session instead of one of the other removable HDD units 300, as necessary. On the other hand, in the event that one of the removable HDD units 300 enters the state wherein the removable HDD unit 300 cannot be used, the session management unit 103 releases the reproduction session established for the removable HDD unit 300 which cannot be used, and establishes the recording session for one of the remaining removable HDD units 300.
On the other hand, in a case wherein the number of the removable HDD units 300 which can be used is greater than the number of the sessions which can be used, the session management unit 103 selects the removable HDD units 300 for which the reproduction session are established, and establishes the reproduction sessions for these removable HDD units 300 thus selected. Upon the recording/reproduction device 10 making a recording request to one of the removable HDD units 300, the session management unit 103 releases the reproduction session established for one of the removable HDD units 300, and establishes the recording session for the removable HDD unit 300 on which the program data is to be recorded. Upon completion of recording of the program, the session management unit 103 releases the recording session, and establishes the reproduction session again as in the previous state. In a case of detection of the new removable HDD unit 300 which can be used, the session management unit 103 establishes the reproduction session instead of one of the other removable HDD units 300, as necessary. On the other hand, in the event that one of the removable HDD units 300 enters the state wherein the removable HDD unit 300 cannot be used, the session management unit 103 releases the reproduction session established for the removable HDD unit 300 which cannot be used, and establishes the reproduction session for one of the remaining removable HDD units 300.
The built-in HDD unit 500 is handled in the same way as in a case wherein a removable HDD unit has been inserted at the time of turning on the power supply. In this case, the built-in HDD unit 500 can be considered to be available at all times after turning on the power supply. Furthermore, an arrangement may be made wherein the recording/reproduction device 10 checks whether or not the built-in HDD unit 500 is available by electric access. For example, an arrangement may be made wherein the system controller 102 issues an “Identify Device” command, stipulated by the ATA, to the built-in HDD unit 500, and upon reception of the response, the recording/reproduction device 10 determines that the built-in HDD unit 500 is available. The built-in HDD unit 500, which has become available, performs the same operation as with the removable HDD unit 300 which has become available.
Let us consider an application of the state-transition diagram shown in
As described above, with the present embodiment, the session management unit 103 assigns the secure sessions, which allow parallel processing, for reproduction with high priority. This allows as large a number of the removable HDD units 300 as possible to enter the standby state for reproduction, thereby reducing delay at the time of reproduction. Furthermore, following the session management unit 103 assigning the secure sessions for reproduction, in the event that there are any remaining secure sessions which allow parallel processing, the session management unit 103 assigns the remaining secure sessions for recording, thereby enabling smooth processing for recording.
As described above, description has been made regarding the present invention with reference to the aforementioned embodiments. The above-described embodiments have been described for exemplary purposes only, and are by no means intended to be interpreted restrictively. Rather, it can be readily conceived by those skilled in this art that various modifications may be made by making various combinations of the aforementioned components or the aforementioned processing, which are also encompassed in the technical scope of the present invention.
While description has been made in the aforementioned embodiments regarding an arrangement wherein the session management unit 103 establishes the single recording session and the single reproduction session for each removable HDD unit 300, an arrangement may be made wherein the session management unit 103 assigns the multiple recording sessions and reproduction sessions for each removable HDD unit 300 in a case wherein the recording/reproduction device 10 has a function for reproducing two or more contents on the display screen divided into multiple regions, at the same time, for example. In this case, such a arrangement wherein the session management unit 103 assigns the secure sessions for reproduction with high priority reduces delay at the time of reproduction in the same way. Furthermore, while description has been made in the aforementioned embodiments regarding an arrangement wherein the removable HDD unit 300 is employed as a storage medium, an arrangement may be made wherein the storage medium is built into the recording/reproduction device 10. Note that the removable HDD unit 300 according to the aforementioned embodiments may be packaged with the recording/reproduction device 10 at the time of shipping. Also, the user may purchase the removable HDD unit 300 from a vendor or the like, separately from the recording/reproduction device 10.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-101497 | Mar 2004 | JP | national |
| 2005-025628 | Feb 2005 | JP | national |
