Method and system for message delivery utilizing zero knowledge interactive proof protocol
First Claim
1. A message delivery system for delivering a message M from an information providing terminal to a user terminal, comprising:
- a user terminal including;
a user communication control unit for controlling a communication with the information provider terminal,a user secret information storage unit for storing a secret information S that is kept in secret by a user,a random number generation unit for generating a random number, anda user computation unit for generating a preresponsive message X and a responsive message Y according to the secret information S and the random number, the preresponsive message X being a message transmitted from the user terminal to the information provider terminal prior to a response by the user to the message M and the response message Y being a message transmitted from the user terminal to the information provider terminal in response to receiving of the message M; and
an information provider terminal including;
an information provider communication control unit for controlling the communication with the user terminal,a message database for storing the message M to be provided to the user by the communication through the information provider communication control unit, anda verification unit for carrying out a user authentication of the user according to a zero knowledge interactive proof protocol using the preresponsive message X and the responsive message Y received from the user terminal through the information provider communication control unit and check bits E, the check bits E being information generated at the information provider terminal from a work key W and transmitted to the user terminal such that the responsive message Y is produced at the user terminal from the preresponsive message X, the check bits E, and the secret information S, the work key W being a key used in enciphering the message M at the time of transmitting the message M from the information provider terminal to the user terminal, and the user authentication checks whether the responsive message Y is a correct response corresponding to the preresponsive message X, the check bits E, and a public information of the user, and authenticates that the user knows the secret information S without leaking the secret information S of the user, while certifying that the user has surely received the check bits E.
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Abstract
A message delivery system which can guarantee the authenticity of a user, the reliability of a message delivery, and the authenticity of the message delivery, while preventing an illegal act, and which can prove them at a later time. The system has an information provider terminal including a user authentication unit for carrying out a user authentication of the user according to a zero knowledge interactive proof protocol using check bits E generated according to a work key W, and a transmission unit for transmitting to the user a ciphertext C in which a message M to be delivered to the user is enciphered according to a secret key cryptosystem by using the work key W, and the check bits E. The system also has a user terminal including a message reception unit for taking out the work key W by using at least the check bits E, and obtaining the message M by deciphering the ciphertext C according to the secret key cryptosystem by using the work key W.
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Citations
13 Claims
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1. A message delivery system for delivering a message M from an information providing terminal to a user terminal, comprising:
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a user terminal including; a user communication control unit for controlling a communication with the information provider terminal, a user secret information storage unit for storing a secret information S that is kept in secret by a user, a random number generation unit for generating a random number, and a user computation unit for generating a preresponsive message X and a responsive message Y according to the secret information S and the random number, the preresponsive message X being a message transmitted from the user terminal to the information provider terminal prior to a response by the user to the message M and the response message Y being a message transmitted from the user terminal to the information provider terminal in response to receiving of the message M; and an information provider terminal including; an information provider communication control unit for controlling the communication with the user terminal, a message database for storing the message M to be provided to the user by the communication through the information provider communication control unit, and a verification unit for carrying out a user authentication of the user according to a zero knowledge interactive proof protocol using the preresponsive message X and the responsive message Y received from the user terminal through the information provider communication control unit and check bits E, the check bits E being information generated at the information provider terminal from a work key W and transmitted to the user terminal such that the responsive message Y is produced at the user terminal from the preresponsive message X, the check bits E, and the secret information S, the work key W being a key used in enciphering the message M at the time of transmitting the message M from the information provider terminal to the user terminal, and the user authentication checks whether the responsive message Y is a correct response corresponding to the preresponsive message X, the check bits E, and a public information of the user, and authenticates that the user knows the secret information S without leaking the secret information S of the user, while certifying that the user has surely received the check bits E. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A message delivery system in which a user receives a message from an information provider, the system comprising:
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an information provider terminal including; a user authentication unit for carrying out a user authentication of the user according to a zero knowledge interactive proof protocol using check bits E generated from a work key W; and a transmission unit for transmitting to the user a ciphertext C and the check bits E, the ciphertext C containing a message M to be delivered to the user which is enciphered according to a secret key cryptosystem by using the work key W; and a user terminal including; a message reception unit for taking out the work key W by using at least the check bits E, and obtaining the message M by deciphering the ciphertext C according to the secret key cryptosystem by using the work key W; wherein the user terminal transmits to the information provider terminal a preresponsive message X prior to a response by the user to the message M, and a response message Y produced from the preresponsive message X, the check bits E, and a secret information S of the user in response to receiving of the message M, and the user authentication checks whether the responsive message Y is a correct response corresponding to the preresponsive message X, the check bits E, and a public information of the user, and authenticates that the user knows the secret information S, without leaking the secret information S of the user, while certifying that the user has surely received the check bits E.
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Specification