Information recording device, information playback device, information recording method, information playback method, and information recording medium and program providing medium used therewith
First Claim
1. An information playback device for playing back information recorded on a recording medium, said information playback device comprising:
- cryptosystem means for executing decryption processing on data read from said recording medium; and
secret-information decoding means for reading secret information stored on said recording medium by executing a data-reading process, which is different from a process of reading content data stored on said recording medium, for generating one or more M-series signals and decoding the secret information using the M-series signals;
wherein said cryptosystem means generates a content-decryption key by using a hash function and, as a key-generating data, the secret information which is decoded after being read from said recording medium in accordance with either an analyzing data-recording key mode or a non-analyzing data-recording key mode, and executes, based on the generated content-decryption key, the decryption processing on the read data; and
wherein said cryptosystem means uses the read secret information to generate the content-decryption key, and the read secret information is allowed to be used only in the generation of the content-decryption key which is executed in said cryptosystem means, without being stored in a storage means which is readable from the outside of said information playback device.
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Abstract
An information recording/playback device stores beforehand, on a recording medium, secret information in which a writing/reading method thereof cannot be analyzed and which can be read only by a special reading method. The secret information is applied to a key for content encryption or decryption when performing recording or playback of contents on the recording medium, such as music data and image data. The secret information is, for example, a stamper ID. By using the stamper ID as secret information, and a master key and a media key which are distributed in a tree-structure key-distribution system, a content-cryptosystem key is generated. Accordingly, each content is allowed to be used in only an appropriate device in which the special reading method for the secret information can be executed and to which the key is distributed by the tree-structure key-distribution system.
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Citations
16 Claims
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1. An information playback device for playing back information recorded on a recording medium, said information playback device comprising:
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cryptosystem means for executing decryption processing on data read from said recording medium; and secret-information decoding means for reading secret information stored on said recording medium by executing a data-reading process, which is different from a process of reading content data stored on said recording medium, for generating one or more M-series signals and decoding the secret information using the M-series signals; wherein said cryptosystem means generates a content-decryption key by using a hash function and, as a key-generating data, the secret information which is decoded after being read from said recording medium in accordance with either an analyzing data-recording key mode or a non-analyzing data-recording key mode, and executes, based on the generated content-decryption key, the decryption processing on the read data; and wherein said cryptosystem means uses the read secret information to generate the content-decryption key, and the read secret information is allowed to be used only in the generation of the content-decryption key which is executed in said cryptosystem means, without being stored in a storage means which is readable from the outside of said information playback device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An information playback method for playing back information from a recording medium, said information playback method comprising:
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a secret-information decoding step which reads secret information stored on said recording medium by executing a data-reading process, which is different from a process of reading content data stored on said recording medium, for generating one or more M-series signals and decoding the secret information using the M-series signals; and a decryption step which generates a content-decryption key by using a hash function and, as a key-generating data, the secret information which is decoded after being read from said recording medium in said secret-information decoding step in accordance with either an analyzing data-recording key mode or a non-analyzing data-recording key mode, and executes, based on the generated content-decryption key, the decryption processing on the read data; wherein said decryption step includes a step which uses the read secret information to generate the content-decryption key, and the read secret information is allowed to be used only in the generation of the content-decryption key which is executed in said cryptosystem means, without being stored in a storage means which is readable from the outside of said information playback device. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification