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US 2004/0111602 A1Published application
Public key cryptograph communication method
AssigneeHitachi, Ltd.
InventorMototsugu Nishioka
Life of this patent
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AssigneeHitachi, Ltd.
InventorMototsugu Nishioka
Estimating the term…
A public key cryptograph communication technology which can be verified to be secure even when an attacker to the public key cryptograph selects a random function giving random oracle is provided. A sender side apparatus 100 generates a cipher text so that it is difficult to calculate partial information with regard to an input value (not finite to message) to a random function as random oracle used in generating the cipher text from the cipher text. And the apparatus 100 generates verification data for verifying that the apparatus 100 knows the input value to the random function as a unit of the cipher text. Then, the apparatus 100 transmits the cipher text to a receiver side apparatus 200. The receiver side apparatus 200 outputs a result of decrypting the cipher text when the verification data included in the received cipher text can be correctly verified.
A public key cryptograph communication method in which a sender side apparatus generates a cipher text of a message by using a random function and a public key of a receiver and transmits the cipher text to a receiver side apparatus, and the receiver side apparatus decrypts the cipher text received from the sender side apparatus by using the random function and a secret key paired with the public key, wherein the sender side apparatus generates the cipher text so that partial information concerning an input value to the random function is non-malleable against the cipher text and transmits the cipher text to the receiver side apparatus.
A public key cryptograph communication method in which a sender side apparatus generates a cipher text of a message by using a hash function and a public key of a receiver and transmits the cipher text to a receiver side apparatus and the receiver side apparatus decrypts the cipher text received from the sender side apparatus by using the hash function and a secret key paired with the public key, wherein
A sender side apparatus for generating a cipher text of a message by using a random function and a public key of a receiver and transmitting the cipher text to a receiver side apparatus, comprising:
A program which is readable by a computer, wherein
Dependencies are inferred from the claim text.