Method and system for digital information protection
First Claim
1. A method for digital information protection in a system in which a user makes an access to a digital information provided by an information center, by connecting a computer card owned by the user to an information terminal device connected with the information center, the method comprising the steps of:
- (a) carrying out a mutual authentication between the computer card and the information terminal device;
(b) carrying out a user authentication by the computer card through the information terminal device;
(c) sending an information request specifying the desired digital information of the user from the information terminal device to the information center by signing and encrypting an information identifier for identifying the desired digital information;
(d) sending the work key for encrypting the desired digital information from the information center to the computer card by a cipher communication using a public key cryptosystem;
(e) obtaining and registering the work key sent from the information center at the computer card, and sending a work key receipt signature from the computer card to the information center;
(f) receiving a work key request message containing a random number from the information terminal device at the computer card, encrypting the work key according to the random number, and sending an encrypted work key from the computer card to the information terminal device;
(g) encrypting the desired digital information specified by the information request by using the work key at the information center, and sending the encrypted digital information from the information center to the information terminal device;
(h) receiving and decrypting the encrypted work key sent from the computer card so as to obtain the work key at the information terminal device, receiving and decrypting the encrypted digital information sent from the information center by using the work key, and providing the decrypted digital information to the user at the information terminal device; and
(i) sending an encrypted information receipt signature from the information terminal device to the information center, and recording the information request, the work key receipt signature, and the encrypted information receipt signature as a ground for charging at the information center.
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Accused Products
Abstract
A digital information protection scheme using an improved security protocol. In a system in which a user makes an access to a digital information provided by an information center by connecting a computer card owned by the user to an information terminal device connected with the information center, a work key for encrypting a desired digital information is delivered from the information center to the computer card through the information terminal device, and the work key is registered in the computer card; the desired digital information encrypted by the work key is delivered from the information center to the information terminal device; and an encrypted digital information delivered from the information center is decrypted at the information terminal device by using the work key registered in the computer card, and a decrypted digital information is provided to the user at the information terminal device.
143 Citations
35 Claims
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1. A method for digital information protection in a system in which a user makes an access to a digital information provided by an information center, by connecting a computer card owned by the user to an information terminal device connected with the information center, the method comprising the steps of:
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(a) carrying out a mutual authentication between the computer card and the information terminal device; (b) carrying out a user authentication by the computer card through the information terminal device; (c) sending an information request specifying the desired digital information of the user from the information terminal device to the information center by signing and encrypting an information identifier for identifying the desired digital information; (d) sending the work key for encrypting the desired digital information from the information center to the computer card by a cipher communication using a public key cryptosystem; (e) obtaining and registering the work key sent from the information center at the computer card, and sending a work key receipt signature from the computer card to the information center; (f) receiving a work key request message containing a random number from the information terminal device at the computer card, encrypting the work key according to the random number, and sending an encrypted work key from the computer card to the information terminal device; (g) encrypting the desired digital information specified by the information request by using the work key at the information center, and sending the encrypted digital information from the information center to the information terminal device; (h) receiving and decrypting the encrypted work key sent from the computer card so as to obtain the work key at the information terminal device, receiving and decrypting the encrypted digital information sent from the information center by using the work key, and providing the decrypted digital information to the user at the information terminal device; and (i) sending an encrypted information receipt signature from the information terminal device to the information center, and recording the information request, the work key receipt signature, and the encrypted information receipt signature as a ground for charging at the information center. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for digital information protection in a system in which a user makes an access to a digital information provided by an information center, by connecting a computer card owned by the user to an information terminal device connected with the information center, the method comprising the steps of:
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(a) carrying out a mutual authentication between the computer card and the information terminal device; (b) carrying out a user authentication by the computer card through the information terminal device; (c) sending an information request specifying the desired digital information of the user from the information terminal device to the information center by signing and encrypting an information identifier for identifying the desired digital information; (d) encrypting the desired digital information specified by the information request by using the work key at the information center, and sending the encrypted digital information from the information center to the information terminal device and the computer card; (e) receiving and storing the encrypted digital information sent from the information center at the information terminal device, and sending an information receipt signature from the computer card to the information center via the information terminal device; (f) delivering the work key for encrypting the desired digital information from the information center to the computer card, and obtaining and registering the work key sent from the information center at the computer card, while returning a delivery certificate from the computer card to the information center; (g) receiving a work key request message containing a random number from the information terminal device at the computer card, encrypting the work key according to the random number, and sending an encrypted work key from the computer card to the information terminal device; (h) receiving and decrypting the encrypted work key sent from the computer card so as to obtain the work key at the information terminal device, decrypting the encrypted digital information stored in the information terminal device by using the work key, and providing the decrypted digital information to the user at the information terminal device; and (i) sending an encrypted information receipt signature from the information terminal device to the information center, and recording the information request, the encrypted information receipt signature, and the delivery certificate as a ground for charging at the information center. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for digital information protection in a system in which a user makes an access to a digital information provided by an information center, by connecting a computer card owned by the user to an information terminal device connected with the information center, the method comprising the steps of:
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delivering a work key for encrypting a desired digital information from the information center to the computer card through the information terminal device, and registering the work key in the computer card; delivering the desired digital information encrypted by the work key from the information center to the information terminal device; and decrypting an encrypted digital information delivered from the information center at the information terminal device by using the work key registered in the computer card, and providing a decrypted digital information to the user at the information terminal device. - View Dependent Claims (26, 27)
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28. A digital information protection system, comprising:
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an information center for providing a digital information; an information terminal device connected with the information center; and a computer card owned by a user, such that the user makes an access to the digital information provided by the information center by connecting the computer card to the information terminal device; wherein the information center, the information terminal device, and the computer card are adapted to; deliver a work key for encrypting a desired digital information from the information center to the computer card through the information terminal device, and register the work key in the computer card; deliver the desired digital information encrypted by the work key from the information center to the information terminal device; and decrypt an encrypted digital information delivered from the information center at the information terminal device by using the work key registered in the computer card, and provide a decrypted digital information to the user at the information terminal device. - View Dependent Claims (29, 30)
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31. An information center for a digital information protection system in which a user makes an access to a digital information provided by the information center by connecting a computer card owned by the user to an information terminal device connected with the information center, wherein the information center, the information terminal device, and the computer card are adapted to:
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deliver a work key for encrypting a desired digital information from the information center to the computer card through the information terminal device, and register the work key in the computer card; deliver the desired digital information encrypted by the work key from the information center to the information terminal device; and decrypt an encrypted digital information delivered from the information center at the information terminal device by using the work key registered in the computer card, and provide a decrypted digital information to the user at the information terminal device; the information center comprising; information storage means for storing the digital information; communication control means for making a communication with the information terminal device; key generation means for generating the work key; encryption means for encrypting the digital information by using the work key; public key cryptosystem means for encrypting the work key in order to make a cipher communication of the work key; and signature conversion means for providing a signature of the information center. - View Dependent Claims (32)
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33. An information terminal device for a digital information protection system in which a user makes an access to a digital information provided by an information center by connecting a computer card owned by the user to the information terminal device connected with the information center, wherein the information center, the information terminal device, and the computer card are adapted to:
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deliver a work key for encrypting a desired digital information from the information center to the computer card through the information terminal device, and register the work key in the computer card; deliver the desired digital information encrypted by the work key from the information center to the information terminal device; and decrypt an encrypted digital information delivered from the information center at the information terminal device by using the work key registered in the computer card, and provide a decrypted digital information to the user at the information terminal device; the information terminal device comprising; first communication control means for making a communication with the information center; second communication control means for making a communication with the computer card; information storage means for storing the digital information; public cryptosystem means for encrypting the work key in order to make a cipher communication of the work key; signature conversion means for providing a signature of the information terminal device; random number generation means for generating a random number; matching means for matching the random number generated by the random number generation means with a random number received from the computer card; secret key storage means for storing a secret key of the information terminal device; decryption means for decrypting an encrypted work key and an encrypted digital information; and secrecy protection means for physically protecting a secrecy of the random number generation means, the matching means, the secret key storage means, and the decryption means.
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34. A computer card for a digital information protection system in which a user makes an access to a digital information provided by an information center by connecting the computer card owned by the user to an information terminal device connected with the information center, wherein the information center, the information terminal device, and the computer card are adapted to:
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deliver a work key for encrypting a desired digital information from the information center to the computer card through the information terminal device, and register the work key in the computer card; deliver the desired digital information encrypted by the work key from the information center to the information terminal device; and decrypt an encrypted digital information delivered from the information center at the information terminal device by using the work key registered in the computer card, and provide a decrypted digital information to the user at the information terminal device; the computer card comprising; communication control means for making a communication with the information terminal device; public cryptosystem means for encrypting the work key in order to make a cipher communication of the work key; signature conversion means for providing a signature of the computer card; and work key storage means for storing the work key. - View Dependent Claims (35)
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Specification