Encryption method, encryption apparatus, recording method, decoding method, decoding apparatus and recording medium
First Claim
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1. A method of encrypting predetermined information by using a predetermined encryption key comprising the steps of:
- hierarchizing the encryption of said encryption key by sequentially encrypting a version of an encryption key from an immediate previously encrypted version of an encryption key by using a one way function, anddecoding said predetermined information by using said hierarchized encryption of said encryption key wherein only a subsequent version excluding a first master version of an encryption key is able to decode the predetermined information of a previous version of an encryption key.
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Abstract
There are provided an encryption method, an encryption apparatus, a recording method, a decoding method, a decoding apparatus and a recording medium in which encryption keys can be managed with ease by hierarchizing encryption keys.
97 Citations
37 Claims
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1. A method of encrypting predetermined information by using a predetermined encryption key comprising the steps of:
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hierarchizing the encryption of said encryption key by sequentially encrypting a version of an encryption key from an immediate previously encrypted version of an encryption key by using a one way function, and decoding said predetermined information by using said hierarchized encryption of said encryption key wherein only a subsequent version excluding a first master version of an encryption key is able to decode the predetermined information of a previous version of an encryption key. - View Dependent Claims (2, 3, 29, 30, 31)
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4. A method of recording predetermined encrypted information on a recording medium comprising the steps of:
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receiving predetermined information encrypted by using an encryption key hierarchized by sequentially encrypting a version of an encryption key from an immediate previously encrypted version of an encryption key by a one way function; and recording said encrypted predetermined information on said recording medium whereby, only a subsequent version excluding a first master version of an encryption key is able to decode the predetermined information of a previous version of an encryption key. - View Dependent Claims (5)
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6. A method of decoding encrypted predetermined information comprising the steps of:
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receiving encrypted predetermined information; and decoding said encrypted predetermined information by using a decoding key corresponding to an encryption key hierarchized by sequentially encrypting a version of an encryption key from an immediate previously encrypted version of an encryption key by using a one-way function whereby, only a subsequent version excluding a first master version of an encryption key is able to decode the predetermined information of a previous version of an encryption key. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for decoding predetermined information by using a predetermined encryption key comprising:
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means for generating encryption keys by hierarchizing the encryption of encryption keys by sequentially encrypting a version of an encryption key from an immediate previously encrypted version of an encryption key by using a one-way function; and means for decoding said predetermined information by using said hierarchized encryption keys whereby, only a subsequent version excluding a first master version of an encryption key is able to decode the predetermined information of a previous version of an encryption key. - View Dependent Claims (16, 17, 32, 33, 34)
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18. An apparatus for decoding encrypted predetermined information comprising:
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means for receiving said encrypted predetermined information; and means for decoding said encrypted predetermined information by using a decoding key corresponding to encryption keys hierarchized by sequentially encrypting a version of an encryption key from an immediate previously encrypted version of an encryption key by using a one way function whereby, only a subsequent version excluding a first master version of an encryption key is able to decode the predetermined information of a previous version of an encryption key. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 35, 36, 37)
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26. A recording medium decodable by a decoding apparatus, in which said recording medium includes a recording signal decodable by said decoding apparatus and said recording signal contains predetermined information encrypted by encryption keys hierarchized by sequentially encrypting a version of an encryption key from an immediate previously encrypted version of an encryption key by using a one-way function whereby,
only a subsequent version excluding a first master version of an encryption key is able to decode the predetermined information of a previous version of an encryption key.
Specification