US5235641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
File encryption method and file cryptographic system
Assignee: Hitachi Ltd
•
Filing: 1991-03-12
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Granted: 1993-08-10
•
Expires: 2011-03-12
Abstract
Abstract In an information processing system having an upper rank apparatus and an external storage device which performs transmission and reception of data between the storage device and the upper rank apparatus, at least one of encryption and decryption of the data by use of an algorithm controlled by a desired data key is performed in the external storage device, while generation, encryption and decryption of the data key are performed on the upper rank apparatus side. By this configuration, the burden of the upper rank apparatus is largely reduced and the secrecy of data stored in the external storage device can be surely kept without spoiling the throughput of the whole system.
Inventors
- 👤 Masafumi Nozawa
- 👤 Akinobu Shimada
- 👤 Toshifumi Nishimura
- 👤 Katsuharu Kakuse
- 👤 Tokuhiro Tsukiyama
- 👤 Kiyoshi Yata
- 👤 Yasuhiro Ishii
- 👤 Kazuo Takaragi
- 👤 Yasushi Kuba
- 👤 Fujio Fujita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:40
CPC Classifications
G; G06; G06F; G06F21/00; G06F21/60; G06F21/62; G06F21/6209; G06F2221/00; G06F2221/21; G06F2221/2107
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
110 words
A file encryption method for use in an information processing system having a hierarchically arranged upper rank apparatus and an external storage device, which method controls transmission and reception of data between said storage device and said upper rank apparatus, comprising the steps of: performing in said external storage device at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus, using an algorithm controlled by a data key; and performing generation, encryption and decryption of said data key in said upper rank apparatus.
Claim 2
Dependent Claim
110 words
A file encryption method for use in an information processing system having a hierarchically arranged upper rank apparatus and an external storage device, which method controls transmission and reception of data between said storage device and said upper rank apparatus, comprising the steps of: performing in said external storage device at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus, using an algorithm controlled by a data key; and performing generation, encryption and decryption of said data key in said upper rank apparatus.
Claim 3
Dependent Claim
108 words
A file cryptographic system comprising: an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which said cryptographic device performs encryption and decryption of a raw data key, and said means in said external storage device performs encryption and decryption of data based on said raw data key received from said upper rank apparatus.
Claim 4
Dependent Claim
108 words
A file cryptographic system comprising: an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which said cryptographic device performs encryption and decryption of a raw data key, and said means in said external storage device performs encryption and decryption of data based on said raw data key received from said upper rank apparatus.
Claim 5
Dependent Claim
63 words
A file cryptographic system according to claim 2, in which, when decryption of said raw data key is performed in said cryptographic device, incomplete decryption is performed at an extent that the decrypted raw data key is breakable by the function of decryption in said external storage device, so that final decryption of said raw data key is performed in said cryptographic device.
Claim 6
Dependent Claim
31 words
A file cryptographic system according to claim 2, in which, when said data transmitted from said upper rank apparatus is encrypted and recorded, the encryption is performed after data compression processing.
Claim 7
Dependent Claim
40 words
A file cryptographic system according to claim 2, in which a data key encrypted by the cryptographic device provided at said upper rank apparatus side and ordinary data encrypted by said data key are stored in the same recording medium.
Claim 8
Dependent Claim
123 words
A file cryptographic system comprising: an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which, when decryption of said raw data key is performed in said cryptographic device, incomplete decryption is performed to an extent that the decrypted raw data key is breakable by the function of decryption in said external storage device, so that final decryption of said raw data key is performed in said cryptographic device.
Claim 9
Dependent Claim
123 words
A file cryptographic system comprising: an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which, when decryption of said raw data key is performed in said cryptographic device, incomplete decryption is performed to an extent that the decrypted raw data key is breakable by the function of decryption in said external storage device, so that final decryption of said raw data key is performed in said cryptographic device.
Claim 10
Dependent Claim
95 words
A file cryptographic system comprising: an upper rank apparatus; an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which, when said data transmitted from said upper rank apparatus is encrypted and recorded, the encryption is performed after data compression processing.
Claim 11
Dependent Claim
95 words
A file cryptographic system comprising: an upper rank apparatus; an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which, when said data transmitted from said upper rank apparatus is encrypted and recorded, the encryption is performed after data compression processing.
Claim 12
Dependent Claim
100 words
A file cryptographic system comprising: an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which a data key encrypted by the cryptographic device provided at said upper rank apparatus side and ordinary data encrypted by said data key are stored in the same recording medium.
Claim 13
Dependent Claim
100 words
A file cryptographic system comprising: an upper rank apparatus; a cryptographic device connected to said upper rank apparatus; and an external storage device, said external storage device including means for performing at least one of encryption of data received from said upper rank apparatus for storage in said external storage device and decryption of data stored in said external storage device and requested by said upper rank apparatus; in which a data key encrypted by the cryptographic device provided at said upper rank apparatus side and ordinary data encrypted by said data key are stored in the same recording medium.
Claim 14
Independent Claim
142 words
A method of effecting secure storage of data in an external storage device by an upper rank apparatus via a storage controller, comprising the steps of: (a) generating a raw data key and encrypting the raw data key in said upper rank apparatus; (b) transferring the raw data key and the encrypted raw data key to said storage controller; (c) storing the raw data key in said storage controller and said encrypted raw data key in a selected storage location in said external storage device; (d) transferring raw data from said upper rank apparatus to said storage controller; (e) encrypting said raw data in said storage controller using the raw data key stored therein and storing said encrypted raw data in said selected storage location in said external storage device; and (f) erasing the raw data key stored in said storage controller.
Claim 15
Independent Claim
142 words
A method of effecting secure storage of data in an external storage device by an upper rank apparatus via a storage controller, comprising the steps of: (a) generating a raw data key and encrypting the raw data key in said upper rank apparatus; (b) transferring the raw data key and the encrypted raw data key to said storage controller; (c) storing the raw data key in said storage controller and said encrypted raw data key in a selected storage location in said external storage device; (d) transferring raw data from said upper rank apparatus to said storage controller; (e) encrypting said raw data in said storage controller using the raw data key stored therein and storing said encrypted raw data in said selected storage location in said external storage device; and (f) erasing the raw data key stored in said storage controller.
Claim 16
Dependent Claim
22 words
The method as defined in claim 9, wherein said step (e) further includes compressing said raw data prior to the encrypting thereof.
Claim 17
Independent Claim
137 words
A method for an upper rank apparatus to access encrypted data stored with an encrypted data key in a storage location of an external storage device via a storage controller, comprising the steps of: (a) transferring the encrypted data key from said storage location of said external storage device to said upper rank apparatus via said storage controller in response to a request by said upper rank apparatus; (b) decrypting the encrypted data key to produce a decrypted data key in said upper rank apparatus; (c) transferring the decrypted data key to said storage controller; (d) transferring said encrypted data from said storage location to said storage controller and decrypting said encrypted data to produce raw data based on decrypted data key in said storage controller; and (e) transferring said raw data to said upper rank apparatus.
Claim 18
Independent Claim
137 words
A method for an upper rank apparatus to access encrypted data stored with an encrypted data key in a storage location of an external storage device via a storage controller, comprising the steps of: (a) transferring the encrypted data key from said storage location of said external storage device to said upper rank apparatus via said storage controller in response to a request by said upper rank apparatus; (b) decrypting the encrypted data key to produce a decrypted data key in said upper rank apparatus; (c) transferring the decrypted data key to said storage controller; (d) transferring said encrypted data from said storage location to said storage controller and decrypting said encrypted data to produce raw data based on decrypted data key in said storage controller; and (e) transferring said raw data to said upper rank apparatus.
Claim 19
Dependent Claim
34 words
A method as defined in claim 11, wherein said encrypted data stored in said storage location is compressed encrypted data, and said step (d) includes decompressing the decrypted data to produce said raw data.
Claim 20
Dependent Claim
58 words
A method as defined in claim 11, wherein said step (b) includes partially decrypting said encrypted data key in said upper rank apparatus to produce said decrypted data key, and said step (d) includes further decrypting said decrypted data key in said storage controller to produce a raw data key which is used to decrypt said encrypted data.
Claim 21
Dependent Claim
27 words
A method as defined in claim 13, wherein said step (e) is followed by a step of (f) erasing the raw data key in said storage controller.
Claim 22
Dependent Claim
21 words
A method as defined in claim 11, wherein said decrypted data key produced in step (b) is a raw data key.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |