IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0655129
(2003-09-05)
|
등록번호 |
US-7693795
(2010-05-20)
|
우선권정보 |
JP-2002-260521(2002-09-05) |
발명자
/ 주소 |
- Yamamichi, Masato
- Matsuzaki, Natsume
- Abe, Toshihisa
- Nakano, Toshihisa
- Miyazaki, Masaya
|
출원인 / 주소 |
|
대리인 / 주소 |
Wenderoth, Lind & Ponack, L.L.P.
|
인용정보 |
피인용 횟수 :
3 인용 특허 :
4 |
초록
▼
Disclosed is a digital work protection system enabling a content distributor to flexibly define usage patterns of content permitted for users. The system is composed of a recording device and a playback device. The recording device acquires a digital work, range information showing a permission rang
Disclosed is a digital work protection system enabling a content distributor to flexibly define usage patterns of content permitted for users. The system is composed of a recording device and a playback device. The recording device acquires a digital work, range information showing a permission range within which the digital work is permitted to be used, and a subrange key for each subrange, generates an encryption key using all the acquired subrange keys, encrypts the digital work based on the encryption key to generate encryption information, and writes the encryption information and the range information to a recording medium. The playback device reads the range information and the encrypted information from the recording medium, acquires a subrange key for each subrange, generates a decryption key using all the acquired subrange keys, decrypts the encrypted information based on the decryption key to generate a digital work, and plays the digital work.
대표청구항
▼
What is claimed is: 1. A recording device for encrypting a digital work that corresponds to a permission range within which the digital work is permitted to be used and for recording the digital work in encrypted form to a recording medium, the recording device comprising: a memory device that stor
What is claimed is: 1. A recording device for encrypting a digital work that corresponds to a permission range within which the digital work is permitted to be used and for recording the digital work in encrypted form to a recording medium, the recording device comprising: a memory device that stores a program, the program when executed causes the recording device to operate as: a digital work acquiring unit that acquires the digital work and range information indicating the permission range in which the digital work is permitted to be used, the permission range including a plurality of subranges, the plurality of subranges being different from other respective subranges, and the range information including a plurality of adoption information, each of the plurality of the adoption information being corresponded to one of the plurality of the subranges and indicating whether a corresponding subrange is to be adopted; a judging unit that judges whether each piece of adoption information indicates that a corresponding subrange is to be adopted; a key acquiring unit that acquires a subrange key for each subrange indicated to be adopted by the corresponding adoption information when the corresponding adoption information indicates that the corresponding subrange is to be adopted, thereby acquiring one or more subrange keys; a key generating unit that generates an encryption key using the one or more acquired subrange keys; an encrypting unit that encrypts the digital work based on the encryption key, thereby generating encrypted information; and a writing unit that writes the range information and the encrypted information to the recording medium. 2. The recording device according to claim 1, wherein said encrypting unit acquires a content key that corresponds to the digital work, encrypt the digital work using the content key to generate an encrypted digital work, encrypt the content key using the encryption key to generate an encrypted content key, and generate the encrypted information that includes the encrypted digital work and the encrypted content key. 3. The recording device according to claim 2, wherein the key generating unit generates, when a plurality of subrange keys are acquired by said key acquiring unit, the encryption key by performing a predetermined arithmetic operation on the plurality of subrange keys. 4. The recording device according to claim 3, wherein said key generating unit generates the encryption key by performing the predetermined arithmetic operation so as to concatenate the acquired plurality of subrange keys. 5. The recording device according to claim 2, wherein the plurality of subranges includes a group-subrange, the group-range encompassing a group formed of a plurality of recording devices, a device-subrange encompassing a specific recording device, a user-subrange encompassing a specific user, and a medium-subrange encompassing a specific recording medium, the permission range includes at least one of the group-subrange, the device-subrange, the user-subrange, and the medium-subrange, the range information includes the plurality of adoption information indicating whether each of the group-subrange, the device-subrange, the user-subrange, and the medium-subrange is to be adopted, said digital work acquiring unit acquires the range information that includes the plurality of adoption information, and said key acquiring unit acquires a subrange key for each subrange that is indicated to be adopted out of the group-subrange, the device-subrange, the user-subrange, and the medium-subrange. 6. The recording device according to claim 2, wherein said digital work acquiring unit acquires the range information and the digital work separately. 7. The recording device according to claim 2, wherein at least one of said key acquiring unit, said key generating unit, and said encrypting unit is included in a portable module that is removable from the recording device. 8. The recording device according to claim 2, wherein the plurality of adoption information included in the range information differs depending on a value for the digital work, and said key acquiring unit acquires the subrange key using the plurality of adoption information that differs depending on the value for the digital work. 9. The recording device according to claim 8, wherein the adoption information included in the range information indicates whether a corresponding subrange is to be adopted so as to impose stricter restrictions on usage of the digital work at an early stage and to impose loosened restrictions on usage of the digital work at a later stage, and said key acquiring unit refers to the range information that imposes the stricter restrictions at the early stage, and to the range information that imposes the loosened restrictions at the later stage when the adoption information indicates that the corresponding subrange is to be adopted so as to impose stricter restrictions on usage of the digital work at the early stage and to impose loosened restrictions on usage of the digital work at the later. 10. The recording device according to claim 8, wherein the adoption information included in the range information indicates whether a corresponding subrange is to be adopted so as to impose stricter restrictions on usage of the digital work that has been used less than a predetermined number of times, and to impose loosened restrictions on usage of the digital work that has been used the predetermined number of times or more, and said key acquiring unit refers to the range information that imposes the stricter restrictions on usage of the digital work that has been used less than the predetermined number of times, and to the range information that imposes the loosened restrictions on usage of the digital work that has been used the predetermined number of times or more when the adoption information indicates that the corresponding subrange is to be adopted so as to impose stricter restrictions on usage of the digital work that has been used less than the predetermined number of times, and to impose loosened restrictions on usage of the digital work that has been used the predetermined number of times or. 11. The recording device according to claim 2, wherein said digital work acquiring unit further acquires other range information indicating at least one other permission range within which the digital work is permitted to be used, the at least one other permission range including at least one subrange adopted out of the one or more subranges, and the other range information including a plurality of adoption information indicating whether a corresponding one of the one or more subranges is to be adopted, said key acquiring unit further acquires a subrange key for each subrange that is indicated to be adopted in the adoption information included in the other range information, thereby acquiring at least one other subrange key, the key generating unit further generates at least one other encryption key using the at least one other subrange key, said encrypting unit further encrypts the digital work based on the at least one other encryption key, thereby generating other encrypted information, and said writing unit further writes the other range information and the other encrypted information to a recording medium. 12. The recording device according to claim 11, wherein said digital work acquiring unit acquires the other range information from a center device that manages the other range information. 13. The recording device according to claim 12, wherein said digital work acquiring unit acquires the other range information on payment of an amount for the other range information. 14. The recording device according to claim 2, wherein the digital work is transferred from a user of the recording device to another user, said digital work acquiring unit further acquires other range information indicating at least one other permission range within which the other user is permitted to use the digital work, the at least one other permission range including at least one subrange adopted out of the one or more subranges, and the other range information including a plurality of adoption information indicating whether a corresponding one of the one or more subranges is to be adopted, said key acquiring unit further acquires a subrange key for each subrange that is indicated to be adopted in the adoption information included in the other range information, thereby acquiring at least one other subrange key, the key generating unit further generates at least one other encryption key using the at least one other subrange key, said encrypting unit further encrypts the digital work based on the at least one other encryption key, thereby generating other encrypted information, and said writing unit writes the other range information and other encrypted information to a recording medium. 15. The recording device according to claim 14, wherein said digital work acquiring unit stores the acquired digital work, the recording device further comprising a deleting unit that deletes the digital work from said digital working acquiring unit. 16. The recording device according to claim 15, wherein said digital work acquiring unit securely acquires the other range information. 17. The recording device according to claim 15, wherein said digital work acquiring unit acquires the other range information with permission by a center device that manages the other range information. 18. The recording device according to claim 15, wherein each of the plurality of subranges includes one of a group-subrange, a device-subrange, a user-subrange and a medium-subrange, the group-range encompassing a group formed of a plurality of recording devices, the device-subrange encompassing a specific recording device, the user-subrange encompassing a specific user, and the medium-subrange encompassing a specific recording medium. 19. The recording device according to claim 1, further comprising: a reading unit that reads the range information and the encrypted information from the recording medium; a key acquiring unit that acquires a subrange key for each subrange that is indicated to be adopted in the adoption information included in the read range information, thereby acquiring at least one subrange key; a key generating unit that generates a decryption key using the acquired one or more subrange keys; a digital work generating unit that decrypts the read encrypted information based on the decryption key, thereby generating a digital work; and a playback unit that plays back the generated digital work. 20. A recording method for encrypting a digital work corresponding to a permission range within which the digital work is permitted to be used and for recording the digital work in encrypted form to a recording medium, the recording method comprising: acquiring the digital work and range information indicating the permission range in which the digital work is permitted to be used, the permission range including a plurality of subranges, the plurality of subranges being different from the other respective subranges, and the range information including a plurality of adoption information, each of the plurality of the adoption information being corresponded to one of the plurality of the subranges and indicating whether a corresponding subrange is to be adopted; judging whether each piece of adoption information indicates that a corresponding subrange is to be adopted; acquiring a subrange key for each subrange that is indicated to be adopted by the corresponding adoption information when the corresponding adoption information indicates that the corresponding subrange is to be adopted, thereby acquiring one or more subrange keys; generating an encryption key using all the acquired one or more subrange keys; encrypting the digital work based on the encryption key, thereby generating encrypted information; and writing the range information and the encrypted information to the recording medium. 21. A recording program stored on a computer-readable medium for causing a computer to perform a method of encrypting a digital work corresponding to a permission range within which the digital work is permitted to be used and for recording the digital work in encrypted form to a recording medium, the method comprising: acquiring the digital work and range information indicating the permission range in which the digital work is permitted to be used, the permission range including a plurality of subranges, the plurality of subranges being different from other respective subranges, the range information including a plurality of adoption information, each of the plurality of the adoption information being corresponded to one of the plurality of the subranges and indicating whether a corresponding subrange is to be adopted; judging whether each piece of adoption information indicates that a corresponding subrange is to be adopted; acquiring a subrange key for each subrange that is indicated to be adopted by the corresponding adoption information when the corresponding adoption information indicates that the corresponding subrange is to be adopted, thereby acquiring one or more subrange keys; generating an encryption key using all the acquired one or more subrange keys; encrypting the digital work based on the encryption key, thereby generating encrypted information; and writing the range information and the encrypted information to the recording medium.
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