Encryption system using device authentication keys
First Claim
1. An encrypted data distributing method comprising:
- a) providing an encryption device authentication key unique to an encryption device prepared by use of a unique identification (ID) of the encryption device;
b) providing a decryption device authentication key unique to the specific decryption device prepared by use of a unique ID of the decryption device;
c) in the encryption device, c-1) preparing an encryption key by use of the encryption device authentication key and the decryption device authentication key;
c-2) encrypting plain text data using the encryption key and sending the resultant cipher text to the decryption device together with attribute information; and
d) in the decryption device, d-1) comparing the decryption device authentication key received from the encryption device with the decryption device authentication key prepared in the decryption device; and
d-2) preparing, when the decryption device authentication keys match, a decryption key by use of the encryption device authentication key and the decryption device authentication key.
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Accused Products
Abstract
An encrypted data distributing method includes preparing cipher text which can be decrypted only by a specific trusted device, and performing encryption and decryption processing at a high speed. An encryption key is prepared using an encryption device authentication key unique to an encryption device and a decryption device authentication key unique to a decryption device, and cipher text is prepared by this encryption key. The authentication keys are also sent to the decryption device. In the decryption device, the decryption device authentication key received from the encryption device is compared with the decryption device authentication key prepared by the decryption device to perform decryption processing only when the authentication keys match.
60 Citations
49 Claims
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1. An encrypted data distributing method comprising:
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a) providing an encryption device authentication key unique to an encryption device prepared by use of a unique identification (ID) of the encryption device;
b) providing a decryption device authentication key unique to the specific decryption device prepared by use of a unique ID of the decryption device;
c) in the encryption device, c-1) preparing an encryption key by use of the encryption device authentication key and the decryption device authentication key;
c-2) encrypting plain text data using the encryption key and sending the resultant cipher text to the decryption device together with attribute information; and
d) in the decryption device, d-1) comparing the decryption device authentication key received from the encryption device with the decryption device authentication key prepared in the decryption device; and
d-2) preparing, when the decryption device authentication keys match, a decryption key by use of the encryption device authentication key and the decryption device authentication key. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An encryption device comprising:
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encryption device authentication key preparing means for preparing an encryption device authentication key unique to the encryption device by use of a unique identification (ID) of the encryption device;
encryption key preparing means for preparing an encryption key by use of the encryption device authentication key and a decryption device authentication key of the specific decryption device, the decryption device authentication key being unique to the decryption device and being prepared using a unique ID of the decryption device; and
an encryption engine that converts plain text into cipher text by use of the encryption key, - View Dependent Claims (13, 14, 15, 16, 17)
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18. An encryption device comprising:
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encryption device authentication key storage means for storing an encryption device authentication key unique to the encryption device, the encryption device authentication key being prepared using a unique identification (ID) of the encryption device;
encryption key preparing means for preparing an encryption key by use of the encryption device authentication key and a decryption device authentication key of the specific decryption device, the decryption device authentication key being unique to the decryption device and being prepared using a unique identification (ID) of the decryption device; and
an encryption engine that converts plain text into cipher text by using the encryption key. - View Dependent Claims (19, 20, 21, 22)
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23. A decryption device which receives cipher text and attribute information from a specific encryption device and decrypts the cipher text, the cipher text being prepared by an encryption key which is prepared using an encryption device authentication key unique to the specific encryption device and a decryption device authentication key unique to the decryption device, and attribute information including the encryption device authentication key and the decryption device authentication key used in preparing the encryption key by the encryption device, the decryption device comprising:
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decryption device authentication key preparing means for preparing the decryption device authentication key unique to the decryption device by use of a unique identification (ID) of the decryption device;
attribute information reading means for reading, from the attribute information, the encryption device authentication key and the decryption device authentication key used in preparing the encryption key in the encryption device;
authentication key comparing means for comparing the decryption device authentication key read by the attribute information reading means with the decryption device authentication key prepared by the decryption device authentication key preparing means;
decryption key preparing means for preparing a decryption key by use of the encryption device authentication key and the decryption device authentication key; and
a decryption engine that converts the cipher text into plain text by use of the decryption key;
wherein the authentication key comparing means prohibits the decryption engine from being started when the decryption device authentication key attached to the cipher text does not match the decryption device authentication key prepared by the decryption device authentication key preparing means. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A decryption device that receives cipher text and attribute information from a specific encryption device and decrypts the cipher text, the cipher text being prepared by an encryption key prepared using an encryption device authentication key unique to the encryption device and a decryption device authentication key unique to the decryption device, and attribute information including the encryption device authentication key and the decryption device authentication key used in preparing the encryption key by the encryption device, the decryption device comprising:
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decryption device authentication key storage means for storing the decryption device authentication key unique to the decryption device, the decryption device authentication key being prepared by using a unique identification (ID) of the decryption device;
attribute information reading means for reading, from the attribute information, the encryption device authentication key and the decryption device authentication key used in preparing the encryption key in the encryption device;
authentication key comparing means for comparing the decryption device authentication key-read by the attribute information reading means with the decryption authentication key stored in by the decryption device authentication key storage means;
decryption key preparing means for preparing a decryption key by using the encryption device authentication key and the decryption device authentication key; and
a decryption engine that converts the cipher text into plain text by using the decryption key, the authentication key comparing means prohibiting the decryption engine from being started when the decryption device authentication key attached to the cipher text does not match the decryption device authentication key stored in the decryption device authentication key storage means. - View Dependent Claims (30, 31, 32, 33, 34)
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35. An encryption/decryption device that prepares cipher text to be sent to a partner device for receiving and decrypting the cipher text or which decrypts cipher text prepared by and received from the partner device, the encryption/decryption device comprising:
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device authentication key preparing means for combining a unique identification (ID) of the device to prepare a first device authentication key unique to the device;
encryption key preparing means for combining the first device authentication key with a second device authentication key unique to the partner device to prepare an encryption key;
an encryption engine that converts plain text into the cipher text by use of the encryption key;
device authentication key comparing means for comparing the second device authentication key attached to the cipher text prepared by the partner device with the first device authentication key prepared by the authentication key preparing means;
decryption key preparing means for combining the second device authentication key attached to the cipher text with the first device authentication key to prepare a decryption key; and
a decryption engine that converts the cipher text into the plain text by use of the decryption key.
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36. An encryption program executable in an encryption device which encrypts plain text to prepare cipher text allowed to be decrypted only by a specific decryption device, the encryption program comprising:
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preparing an encryption key using an encryption device authentication key unique to the encryption device and a decryption device authentication key unique to the decryption device, the encryption device authentication key having been prepared using a unique identification (ID) of the encryption device, and the decryption device authentication key having been prepared using a unique ID of the decryption device;
aconverting the plain text into the cipher text by use of the encryption key, and attaching to the cipher text attribute information including the encryption device authentication key and the decryption device authentication key. - View Dependent Claims (37, 38, 39, 40, 41)
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42. A decryption program executable in a decryption device which receives cipher text and attribute information from a specific encryption device and decrypts the cipher text, the cipher text being prepared by an encryption key prepared using an encryption device authentication key unique to the encryption device and a decryption device authentication key unique to the decryption device, and the attribute information including the encryption device authentication key and the decryption device authentication key which are used in preparing the cipher text, the decryption program comprising:
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(a) comparing the decryption device authentication key attached to the ciphertext with a decryption device authentication key which has been prepared or stored in the decryption device using a unique identification (ID) of the decryption device;
(b) preparing, when the decryption device authentication key received from the encryption device matches the decryption device authentication key prepared in the decryption device, a decryption key by use of the decryption device authentication key and the encryption device authentication key attached to the cipher text; and
(c) converting the cipher text into plain text by use of the decryption key. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49)
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Specification