ENCRYPTION SYSTEM WITH TIME-DEPENDENT DECRYPTION
First Claim
1. An encryption system with time-dependent decryption, including a time-key manager for guaranteeing that a time for enabling decryption of information is limited, (1) wherein, upon receipt of a request from an information server, said time-key manager transmits to said information server a time-key certificate including disclosure time information and a public key for encryption;
- and (2) wherein said information server transmits to an information user information encrypted using said public key, which is included in said time-key certificate, and said time-key manager, following the receipt of a request for a decryption key from said information user, transmits said decryption key to said information user at such time said disclosure time has been reached.
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Accused Products
Abstract
An object of the invention is to provide an encryption system and method for inhibiting the decryption of encrypted data unless a decryption condition is satisfied. Thus, according to the present invention, in order to provide the encryption system for inhibiting the decryption of encrypted data unless a decryption condition is satisfied, decryption enabled time is designated as a decryption condition, and an encryption system incorporating time-dependent decryption is constituted by a time-key certificate and a time-key certificate manager. A time-key certificate is employed when a third party proves that a public encryption key added to the certificate satisfies the decryption condition. The time-key certificate manager issues a time-key certificate and then manages a decryption key.
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Citations
14 Claims
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1. An encryption system with time-dependent decryption, including a time-key manager for guaranteeing that a time for enabling decryption of information is limited,
(1) wherein, upon receipt of a request from an information server, said time-key manager transmits to said information server a time-key certificate including disclosure time information and a public key for encryption; - and
(2) wherein said information server transmits to an information user information encrypted using said public key, which is included in said time-key certificate, and said time-key manager, following the receipt of a request for a decryption key from said information user, transmits said decryption key to said information user at such time said disclosure time has been reached.
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2. A time-key manager for guaranteeing that a time for enabling decryption of information is limited, comprising:
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(1) means for, upon receipt of a request from an information server, transmitting to said information user a time-key certificate including disclosure time information and a public key for encryption; and
(2) means for, after said information server transmits to an information user information encrypted using said public key, which is included in said time-key certificate, receiving a request for a decryption key from said information user and transmitting said decryption key to said information user at such time said disclosure time has been reached.
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3. A disclosure time designation file transfer system, which includes a time-key manager for guaranteeing that a time for enabling decryption of an encrypted file is limited,
(1) wherein, upon receipt of a request from an information server, said time-key manager transmits to said information server a time-key certificate including disclosure time information and a public key for encryption; - and
(2) wherein said information server transmits to an information user said file encrypted using said public key, which is included in said time-key certificate, and said time-key manager, following the receipt of a request for a decryption key from said information user, transmits said decryption key to said information user at such time said disclosure time has been reached.
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4. An electronic tendering system, which includes a time-key manager for guaranteeing that a time for enabling decryption of tender information is limited,
(1) wherein, upon receipt of a request from an order receiver, said time-key manager transmits to said order receiver a time-key certificate including disclosure time information and a public key for encryption; - and
(2) wherein said order receiver transmits to an order submitter said tender information encrypted using said public key, which is included in said time-key certificate, and said time-key manager, following the receipt of a request for a decryption key from said order submitter, transmits said decryption key to said order submitter at such time said disclosure time has been reached. - View Dependent Claims (6)
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5. An electronic tendering system, which includes a time-key manager, for guaranteeing that a time for enabling decryption of tender information is limited, and a tender manager for transmitting messages exchanged by an order receiver and an order submitter,
(1) wherein, upon receipt of a request from an order receiver, said tender manager acquires from said time-key manager a time-key certificate, which includes disclosure time information and a public key for encryption, and transmits said time-key certificate to said order receiver; -
(2) wherein said tender manager receives tender information that said order receiver has encrypted using said public key included in said time-key certificate; and
(3) wherein, upon receipt of a request from said order submitter, said tender manager acquires a decryption key from said time-key manager after said disclosure time has been reached, and transmits said decryption key to said order submitter.
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7. A tender manager for guaranteeing that a time for enabling decryption of tender information is limited, comprising:
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(1) means for, upon receipt of a request from an order receiver, acquiring from said time-key manager a time-key certificate, which includes disclosure time information and a public key for encryption, and for transmitting said time-key certificate to said order receiver;
(2) means for receiving tender information that said order receiver has encrypted using said public key included in said time-key certificate; and
(3) means for, upon receipt of a request from said order submitter, acquiring a decryption key from said time-key manager after said disclosure time has been reached, and transmitting said decryption key to said order submitter.
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8. An electronic safe system, which includes a time-key manager for guaranteeing that a time for enabling decryption of electronic money information is limited,
(1) wherein, upon receipt of a request from a depositor, said time-key manager transmits to said depositor a time-key certificate including disclosure time information and a public key for encryption; - and
(2) wherein said depositor transmits to a bank said electronic money information encrypted using said public key, which is included in said time-key certificate, and said time-key manager, following the receipt of a request for a decryption key from said bank, transmits said decryption key to said bank after said disclosure time has been reached. - View Dependent Claims (10)
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9. An electronic safe system, which includes a time-key manager for guaranteeing that a time for enabling decryption of electronic money information is limited, and an electronic money manager for transmitting messages exchanged by a depositor and a bank,
(1) wherein, upon receipt of a request from a depositor, said electronic money manager acquires from said time-key manager a time-key certificate, which includes disclosure time information and a public key for encryption, and transmits said time-key certificate to said depositor; -
(2) wherein said electronic money manager receives electronic money information that said depositor has encrypted using said public key included in said time-key certificate; and
(3) wherein, upon receipt of a request from said bank, said electronic money manager acquires a decryption key from said time-key manager after said disclosure time has been reached, and transmits said decryption key to said bank.
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11. An electronic money manager for guaranteeing that a time for enabling decryption of electronic money information is limited, comprising:
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(1) means for, upon receipt of a request from a depositor, acquiring from said time-key manager a time-key certificate, which includes disclosure time information and a public key for encryption, and for transmitting said time-key certificate to said depositor;
(2) means for receiving electronic money information that said depositor has encrypted using said public key included in said lime-key certificate; and
(3) means for, upon receipt of a request from said bank, acquiring a decryption key from said time-key manager after said disclosure time has been reached, and for transmitting said decryption key to said bank.
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12. A data library system, which has a time-key certificate manager and a data library and which has a disclosure time control function,
(1) wherein upon receipt of a request from an information server said time-key certificate manager sends to said information server a time-key certificate that includes disclosure time information and a public key for encryption; -
(2) wherein said data library receives from said information server encrypted data, including data that has been encrypted by employing said public key in said time-key certificate;
(3) wherein said data library transmits said encrypted data to an information user; and
(4) wherein, upon receipt of a request from said information user, said time-key certificate manager compares a current time with a time for enabling decryption of said time-key certificate and transmits a decryption key to said information user when said current time satisfies a condition for decryption or does not transmit said decryption key when said current time does not satisfy said condition for decryption.
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13. A time-key management method for guaranteeing that a time for enabling decryption of information is limited, comprising the steps of:
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(1) upon receipt of a request from an information server, transmitting to an information user a time-key certificate including disclosure time information and a public key for encryption; and
(2) after said information server transmits to said information user information encrypted using said public key, which is included in said time-key certificate, receiving a request for a decryption key from said information user and transmitting said decryption key to said information user after said disclosure time has been reached.
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14. A storage medium for storing a program for performing time-key management to guarantee that a time for enabling decryption of information is limited, said program comprising:
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(1) a function for, upon receipt of a request from an information server, transmitting to an information user a time-key certificate including disclosure time information and a public key for encryption; and
(2) a function for, after said information server transmits to said information user information encrypted using said public key, which is included in said time-key certificate, receiving a request for a decryption key from said information user and for transmitting said decryption key to said information user after said disclosure time has been reached.
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Specification