JP2001043618A - Electronic apparatus having digital interface control function and cryptoanalysis function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure picture recording of a reserved program by building a network with plural electronic apparatus connected to a serial data bus such that the destination side electronic apparatus executes mute recording if the cryptoanalysis of the encrypted contents of the source side electronic apparatus is infeasible at the time these contents are transmitted to the destination side electronic apparatus. SOLUTION: When the trigger of picture recording execution arises or during the execution of picture recording, the copy protection status of the contents of an Iso signal (isochronous signal) of a serial data bus (IEEE1394 serial data bus) inputted to the destination side electronic apparatus (picture recording apparatus) is checked. When copying is prohibited, the input contents are subjected to mute picture recording. When copying is feasible but the cryptoanalysis processing is necessary, certification is made that the apparatus is the source side apparatus. In the case of okay, an cryptoanalysis key is determined by calculation. In case of a failure, the mute picture recording is carried out. The content picture recording is execute if the copying is feasible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electronic device having a digital interface control function and a decryption function, and more particularly to an electronic device connected by an IEEE 1394 serial data bus.

[0002]

2. Description of the Related Art In a digital AV system according to the prior art, a network is constructed by connecting electronic devices having a digital interface control function and a decryption function via a serial data bus. These connected electronic devices include a decryption function (AKE function system; Out)
Hentication and Key Excha
device equipped with an NRD (Integrated Rec.) which is a satellite broadcast receiving device.
Eve Decoder) or DV that is a recording device
HS (Digital Video Home System) and the like exist.

FIG. 3 shows a state in which devices provided with the IEEE 1394 interface and having a decryption function are connected by a serial data bus. Among them, an AKE function system constituting the decryption function is shown in FIG. , A specific device A, B connected via a bus, equipped with the same decryption function, and a storage 11 for storing contents from the source device to the destination device, and a recognition and key exchange. Subsystem (Authentication and Key)
Exchange Subsystem (AKE function system) 12 and content decryption subsystem 13
And an IEEE 1394 interface 14 having a protocol for connecting to a source-side device via a bus.

The basic concept of the authentication and key exchange subsystem (AKE function system) 12 having such a configuration will be described. This is a system in which contents handled on a serial data bus can be encrypted and sent at the time of sending to protect the contents. In order to input the encrypted data and display it on a monitor or to record on a recording device, the code must be decrypted. Only after decrypting the code can the original content be projected and recorded. The degree of encryption, that is, the copy protection status (Copy Protection Status)
Is, for example, DCTP (Digital Transm
issue Content Protection
n) is EMI (Encryption Mode I)
ndicator), and the degree to which copying should be performed is set. The types of the degree are copy free (copy free),
Copy Never (Copy Ne)
ver) Copy one that can be copied for one generation only
Generation (Copy One Generator)
No.) No More Copies (No Mor), indicating that one generation has already been copied once
e Copies). In order to protect the content, information indicating the degree of encryption is marked on the content, and a receiving device (recording device in the embodiment) capable of externally inputting a signal is input. With this information of the content, it is instantaneously determined whether or not it is necessary to decrypt the content.

On the other hand, if it is necessary for the source device to encrypt and transmit the content in accordance with the encryption information of the content, the source device encrypts the content and transmits the content on the serial data bus (iLINK in the embodiment). If the input content has been encrypted, the destination-side device (recording device in the embodiment) performs processing for decrypting the content together with the source-side device, and exchanges some necessary keys (Keys). And decrypt the code. For example,
In DTCP, there are three types of keys. Authentication key (Au
dention key and exchange key (E)
xchangeKey) and content key (Cont)
ent Key). The authentication key is used to encrypt the exchange key and is established during authentication. The exchange key is a copy-written content stream (Co
pyratured Content Stream)
Used to set up and manage security for The last content key is used to encrypt and decrypt the exchanged content.

Next, a description will be given, with reference to the flow chart of FIG. 5, of a technique for decryption processing and recording in an electronic device having a digital interface control function and a decryption function in such a configuration.

First, it is determined whether or not there is a recording request to a destination-side device (in this case, a recording device) (step ST11).

When a recording request is issued, that is, when a trigger for recording execution is generated, or during recording, a serial data bus (iL
INK), the copy protection status of the Iso signal content (Copy Protection St).
atus) is checked (step ST12). If the status is a status that prohibits copying, the recording is not executed or the recording is stopped. If the recording is not completed, the copy protection status is checked. This is performed until the end of recording (step ST1).
3, ST14).

If the copy protection status of the input content is copy free, the input original content is recorded, and if the recording is not completed, the status contents are repeatedly checked (steps ST15, ST16, ST14). ).

In step ST15, if the copy protection status of the input content is a status that can be copied but must be decrypted, authentication is performed with the source device that is transmitting the input content. It is determined whether or not it is necessary to correct the password. If it is not necessary to perform the authentication again, it is determined whether or not the authentication is OK (steps ST17 and ST18).

If the authentication is OK, it is examined whether or not the decryption key needs to be updated. If the decryption key needs to be updated, a decryption key is calculated and sent to the decryption IC ( Step STST19).

In step ST18, if the authentication is not OK, authentication with the source side device is performed, and if this authentication is completed or if the authentication process fails even after five attempts, the recording execution is stopped. (Step ST21, S
T22, ST23, ST24). After stopping the recording,
Even if the copy protection status of the content input to the recording device changes to a copyable status, recording is not performed until the next recording execution trigger occurs.

In step 21, if the authentication processing with the source device is completed successfully, a content key is obtained, and a decryption key is sent to the decryption IC. (Steps ST22, ST25, ST2)
6, ST27).

[0014]

However, in an electronic device which can be connected via an IEEE 1394 serial data bus in the prior art, the encryption level (copy protection status) of the content must not be strongly copied. In general, if it is at a copyable level but cannot be decrypted for some reason when attempting to decrypt the electronic device, it is common practice not to perform the recording or to stop the recording. For example, a satellite broadcast receiver IRD (Inte
When a source device including a tuner device such as a graded receiver (Decoder) and a destination device, which is a DVHS, which is a recording / playback device, are connected by an IEEE1394 serial data bus, the DVRD is set to a timer reservation from the IRD. , The IRD is turned on at the reserved start time, receives the broadcast channel of the set program, makes the DVHS powered on, and executes the recording. And

A transition time is required for an electronic device to be turned on from power off or to transition from a stopped state to a recording state. In most cases, such an electronic device is tens of seconds from the reserved start time. It is designed so that power is turned on early and recording is started slightly before the set time. By doing so, recording can always be performed at the start time.

Here, for example, when a program or a commercial before a reserved program has a protection level at which copying is not possible, the start time of the reserved program is set shortly before the start time of the reserved program to ensure recording. Therefore, the copy protection of the content input to the recording device at the start of recording is read, and it is determined that copying is not possible.

In such a case, if the specification is to stop recording, it means that the program to be actually recorded is a program that can be copied but cannot be recorded.

For example, as shown in FIG. 6, in Europe (Germany) and the like, when recording is started by actually pressing the recording key instead of scheduled recording, several minutes are required to reliably record the program from the beginning. There is a tendency for users to start recording in advance, and even such a user detects uncopiable content at the time of executing recording several minutes ago, immediately stops recording, and even if a desired reserved program can be copied It will not be possible to record even content that is difficult.

As another example, as shown in FIG.
If a non-copyable content was already recorded but a copy-free program was later overwritten on a recording medium (for example, a tape) several times, it was copied between a certain program and a certain program. Impossible content may remain. When dubbing such a recording medium to another medium, even if it is attempted to perform the dubbing recording entirely, the recording is stopped when a portion that cannot be copied is detected. For the part that is earlier than the part where the uncopyable part is detected, the part that can be copied must be detected earlier and the recording must be newly started.

Further, if copy protection status information is exchanged via communication or the like, if a noise occurs for a moment and it is determined that copying is not possible, if the recording stop specification is used, automatic Cannot be recovered.

Therefore, when recording the encrypted content, there is a problem to be solved in that the content can be recorded by decrypting the content to be actually recorded.

[0022]

In order to solve the above-mentioned problems, an electronic device having a digital interface control function and a decryption function according to the present invention comprises a network constructed by a plurality of electronic devices connected to a serial data bus. When the encrypted content in the source-side electronic device is transmitted to the destination-side electronic device and the content cannot be decrypted, the destination-side electronic device performs mute recording. That is.

The recording of the mute when the decryption cannot be performed is to be performed until the recording is completed. The serial data bus is an IEEE 1394 serial data bus, the source electronic device is an IRD, The destination-side electronic device is a recording device.

As described above, when recording a content that cannot be decrypted, mute recording is performed so that the content is not affected by the copy status before the desired content, and the content is copied based on the copy status of the desired content. It becomes possible to record.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an electronic device having a digital interface control function and a decryption function according to the present invention will be described with reference to the drawings. still,
The same components as those described in the related art will be described with the same reference numerals.

The configuration of an electronic device having a digital interface control function and a decryption function according to the present invention has the same configuration as that of FIG. 4 described in the related art. The following description focuses on those specific to the present invention.

In the present invention, when a trigger for recording execution occurs or during recording execution, the serial data bus (in the embodiment, the IEEE1394 serial data bus) input to (the recording device of) the destination-side device. 2) Check the copy protection status of the content of the Iso signal (isochronous signal). If the status indicates that copying is prohibited, the audio and video signals of the input content are immediately muted and executed. If the status indicates that copying is possible but decryption processing must be performed, authentication is performed with the source device that is transmitting the input content, and O
If K, a decryption key is calculated by calculation. If the authentication fails, the recording is muted and executed. Then, during recording, the copy protection status of the content input to the recording device is continuously checked, and if it changes to a copyable one, the mute recording is immediately released if decryption is unnecessary. Then, the input content is recorded, and if decryption processing is necessary, authentication is performed with the source device that sends out the input content. If the authentication is OK, a decryption key is calculated by calculation. If the authentication fails, the recording is muted and executed.

The invention of the present application for recording with such muting will be described in more detail with reference to the flowchart of FIG. 1 referring to the block diagram of FIG.

First, it is determined whether or not there is a recording request to the destination side device (step ST3).
1).

When a recording request is issued, that is, when a recording execution trigger is generated, or during recording execution, the copy protection status (Copy P) of the Iso signal content on the serial data bus input to the recording device is input.
The protection status is checked (step ST32). If the status is a status prohibiting copying, a dummy Iso signal (mute) is recorded, and if the recording is not completed, the copy protection status is repeatedly checked again until the recording is completed (step ST33, S
T34).

If the copy protection status of the input content is copy free, the input original content is recorded, and if the recording is not completed, the status content is repeatedly checked (steps ST35, ST36, ST34). ).

In step ST35, if the copy protection status of the input content is a status that can be copied but the decryption process must be performed, authentication is performed with the source device that is transmitting the input content. It is determined whether or not the authentication needs to be corrected. If it is not necessary to perform the authentication again, it is determined whether or not the authentication is OK (steps ST37 and ST38).

If the authentication is OK, it is examined whether or not the decryption key needs to be updated. If the decryption key needs to be updated, a decryption key is calculated and sent to the decryption IC ( Step ST39).

In step ST38, if the authentication is not OK, the authentication with the source device is performed. If the authentication is completed, or if the authentication process fails even after five attempts, a dummy Iso signal ( Mute) (steps ST41, ST42, ST43, ST4)
4).

In step 42, if the authentication process with the source device is completed successfully, the content key is obtained, the decryption key is sent to the decryption IC, and the decrypted content is recorded. If not, the copy protection status of the content is checked (steps ST45, ST46, ST47).

As described above, when the recording is executed before the reserved content or the content to be recorded, the recording is muted, so that the copy protection status before the desired content is not affected. That is, as shown in FIG. 2, there is a program for which a reservation program is desired to be executed, and the copy protection status of the program is not copyable, or the device for which the recording is to be performed cannot copy at that time. Thus, if the recording device starts recording before the start time of the program reserved for executing the reserved program, the reserved program can be reliably recorded. The immediately preceding program is not limited to the same channel, and indicates a program that is being received when the recording device starts recording. The same applies to a case where the recording is executed before the start time of the program to be recorded, not limited to the scheduled recording.

As shown in FIG. 3, there are recording media for which dubbing is desired to be performed, and the recording media from which dubbing is to be performed are those whose copy protection status can be copied and those which cannot be copied. In this case, the so-called "whole dubbing" can be executed even when there is a mixture of.

[0038]

As described above, an electronic device having a digital interface control function and a decryption function according to the present invention performs mute recording when recording a content that cannot be decrypted. In addition, recording can be performed based on the copy status of the desired content without being affected by the copy status before the desired content, and there is an effect that the reserved recorded program can be reliably recorded.

[Brief description of the drawings]

FIG. 1 is a flowchart for recording a mute according to the present invention.

FIG. 2 is an explanatory diagram showing a state of input content and a state of content recorded by a recording device in the case of performing the same scheduled recording.

FIG. 3 is an explanatory diagram showing a comparison between input content of the recording device and recorded content of the recording device at the time of dubbing.

FIG. 4 is a block diagram showing a decryption function.

FIG. 5 is a flowchart of a conventional technique in which recording is stopped when copying is prohibited.

FIG. 6 is an explanatory diagram showing a copy status when a reserved program is recorded in the related art.

FIG. 7 is an explanatory diagram showing the status of copying when repeatedly recording such as dubbing in the related art.

[Explanation of symbols]

11; content source destination storage, 12; authentication and key exchange subsystem, 13;
Content Decryption Subsystem, 14; IEEE13
94 interface

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hisami Tamai 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5D044 AB05 AB07 BC01 CC03 GK11 GK17 HL08 HL11 JJ05

Claims (4)

[Claims] 1. A system for constructing a network with a plurality of electronic devices that can be connected to a serial data bus, the system being adapted to record encrypted content of a source electronic device on a destination electronic device. An electronic device having a digital interface control function and a decryption function, wherein when the encrypted content cannot be decrypted, the destination electronic device records a mute. 2. The recording of a mute when decryption cannot be performed until recording is completed.
An electronic device having a digital interface control function and a decryption function according to the above. 3. The method according to claim 1, wherein the serial data bus is an IEEE13.
The electronic device according to claim 1, wherein the electronic device has a digital interface control function and a decryption function. 4. The electronic device having a digital interface control function and a decryption function according to claim 1, wherein said source-side electronic device is an IRD, and said destination-side electronic device is a recording device.