Unauthorized Device Detection Device And Unauthorized Device Detection System
To provide an unauthorized device detection system capable of finding and specifying a device that was manufactured or altered unauthorizedly. A DVD player 400 a writes its own device ID to a memory card 200 a . When a user purchases content, a register device 300 reads a media ID and the device ID from the memory card 200 a , and transmits the media ID and the device ID to a management server device 100 . The management server device 100 calculates, based on pairs of media IDs and device IDs stored beforehand and the received pair of media ID and device ID, a total number of media IDs corresponding to the received device ID, and compares the calculated total number with a threshold value. If the total number exceeds the threshold value, the management server device 100 judges that the DVD player identified by the received device ID is an unauthorized device.
1 . A detection device for detecting an unauthorized device manufactured by copying, comprising:
a media number storage unit operable to store a total media number corresponding to a device identifier, the total media number being a total number of rewritable portable media used by one or more devices, including a target device, that hold the device identifier;
a comparison unit operable to compare the total media number with a predetermined threshold value used for unauthorized device detection; and
an identifier storage unit operable to store the device identifier if the total media number is greater than the threshold value.
2 . The detection device of claim 1 , further comprising:
a calculation unit that includes:
an acquisition unit operable to acquire, from a rewritable portable medium used by the target device, a media identifier for identifying the portable medium and the device identifier held by the target device;
a storage unit operable to store, in correspondence with a device identifier held by each past target device, one or more media identifiers respectively for identifying one or more rewritable portable media used by the past target device; and
a calculating unit operable to calculate, using the stored device identifier and one or more media identifiers and the acquired device identifier and media identifier, a total number of media identifiers corresponding to a same device identifier as the acquired device identifier, as the total media number, and write the calculated total media number to the media number storage unit.
3 . The detection device of claim 2 ,
wherein the comparison unit further compares the total media number with a warning value that is smaller than the threshold value, and
the identifier storage unit further stores the device identifier if the total media number is no greater than the threshold value but is greater than the warning value.
4 . The detection device of claim 2 ,
wherein the target device is a playback device for decrypting encrypted content and playing back the decrypted content, and
the detection device further comprises:
a prohibition unit operable to prohibit to output a decryption key used for decrypting the encrypted content to the portable medium, if the total media number is greater than the threshold value; and
an output unit operable to output the decryption key to the portable medium, if the total media number is no greater than the threshold value.
5 . The detection device of claim 1 for detecting an unauthorized device manufactured by copying, comprising:
a series number storage unit operable to store a total series number corresponding to a device identifier, the total series number being a total number of viewing history series of content viewed by one or more devices, including a target device, that hold the device identifier;
a comparison unit operable to compare the total series number with a predetermined threshold value used for unauthorized device detection; and
an identifier storage unit operable to store the device identifier if the total series number is greater than the threshold value.
6 . The detection device of claim 1 for detecting an unauthorized device manufactured by copying, comprising:
a storage unit operable to store, in correspondence with a device identifier held by each past target device, one or more content identifiers respectively for identifying one or more sets of content viewed by the past target device;
an acquisition unit operable to acquire, from a rewritable portable medium used by a target device, one or more content identifiers respectively for identifying one or more sets of content viewed by the target device and a device identifier held by the target device;
an extraction unit operable to extract one or more content identifiers corresponding to a same device identifier as the acquired device identifier, from the storage unit;
a comparison unit operable to compare the extracted one or more content identifiers and the acquired one or more content identifiers; and
a registration unit operable to register the acquired device identifier to an unauthorized device list, if none of the extracted one or more content identifiers matches any of the acquired one or more content identifiers.
7 . The detection device of claim 6 ,
wherein the storage unit further stores, in a one-to-one correspondence with the one or more content identifiers, one or more viewing ordinal numbers representing an order in which the one or more sets of content identified by the one or more content identifiers were viewed by the past target device,
the acquisition unit further acquires, in a one-to-one correspondence with the one or more content identifiers, one of more viewing ordinal numbers representing an order in which the one or more sets of content identified by the one or more content identifiers were viewed by the target device,
the extraction unit further extracts one or more viewing ordinal numbers corresponding to the one or more content identifiers that correspond to the same device identifier as the acquired device identifier, from the storage unit,
the comparison unit further compares the extracted one or more viewing ordinal numbers and the acquired one or more viewing ordinal numbers, and
the registration unit further registers the acquired device identifier to the unauthorized device list, if the extracted one or more content identifiers match the acquired one or more content identifiers but a viewing ordinal number corresponding to one of the extracted one or more content identifiers is different from a viewing ordinal number corresponding to a matching one of the acquired one or more content identifiers.
8 . The detection device of claim 6 ,
wherein the target device is a playback device for decrypting encrypted content and playing back the decrypted content, and
the detection device further comprises:
a prohibition unit operable to prohibit to output a decryption key used for decrypting the encrypted content to the portable medium, if none of the extracted one or more content identifiers matches any of the acquired one or more content identifiers; and
an output unit operable to output the decryption key to the portable medium, if any of the extracted one or more content identifiers matches any of the acquired one or more content identifiers.
9 . A playback device for playing back content, comprising:
an identifier storage unit operable to store a device identifier for identifying the playback device;
a history storage unit operable to store, each time content is played back, playback history information regarding the playback of the content together with a playback ordinal number of the content; and
a write unit operable to write the device identifier, the playback history information, and the playback ordinal number to a portable medium.
10 . A detection system including: a detection device for detecting an unauthorized device manufactured by copying; and a target device,
the detection device comprising:
a media number storage unit operable to store a total media number corresponding to a device identifier, the total media number being a total number of rewritable portable media used by one or more devices, including the target device, that hold the device identifier;
a comparison unit operable to compare the total media number with a predetermined threshold value used for unauthorized device detection; and
an identifier storage unit operable to store the device identifier if the total media number is greater than the threshold value, and
the target device comprising:
a write unit operable to write the device identifier held by the target device, to a portable medium.
11 . A detection method used in a detection device for detecting an unauthorized device manufactured by copying and including a media number storage unit operable to store a total media number corresponding to a device identifier, the total media number being a total number of rewritable portable media used by one or more devices, including a target device, that hold the device identifier, the detection method comprising steps of:
comparing the total media number with a predetermined threshold value used for unauthorized device detection; and
an identifier storage unit operable to store the device identifier if the total media number is greater than the threshold value.
12 . A computer program for unauthorized device detection used in a detection device for detecting an unauthorized device manufactured by copying and including a media number storage unit operable to store a total media number corresponding to a device identifier, the total media number being a total number of rewritable portable media used by one or more devices, including a target device, that hold the device identifier, the computer program comprising steps of:
comparing the total media number with a predetermined threshold value used for unauthorized device detection; and
storing the device identifier if the total media number is greater than the threshold value.
13 . The computer program of claim 12 recorded on a computer-readable recording medium.