Anonymous credential authentication system and method thereof

A method for authentication of an anonymous credential authentication system in a user device, the method comprising:

• transmitting, to a credential issuance processor, a credential issuance request message including multiple pieces of attribute information constituting personal information, a commitment value for the multiple pieces of attribute information, a zero knowledge proof value for the commitment value, and a user signature value for the commitment value;
• getting a credential including a signature value of the credential issuing processor generated by using an issuing key and random values selected from an integer set representing the multiple pieces of attribute information issued from the credential issuing processor;
• generating an attribute authentication signature key by combining a system public key published by the credential issuing processor, the credential and the multiple pieces of attribute information;
• presenting an anonymous credential signature value indicating that a proposition information set is satisfied using the credential and the attribute authentication signature key;
• and
• receiving a verification result for the anonymous credential signature value,
• wherein the system public key includes at least one of a first public parameter providing a signer authentication and a second public parameter providing a linking check between two signature values, and
• wherein the presenting includes:
• generating a value providing the signer authentication using the first public parameter and the signature value of the credential issuing processor;
• calculating a proof value that proves each piece of attribute information;
• and
• generating a zero-knowledge proof value for qualification requirements among a proposition information.

An anonymous credential authentication system for authenticating a user using an anonymous credential method, the anonymous credential authentication system comprising:

• a credential issuing processor that issues a credential combined with multiple pieces of attribute information constituting personal information in response to a system public key to the user;
• an opening processor that generates and outputs signer authentication information for confirming a signer of an anonymous credential signature value when the anonymous credential signature value indicating that setting proposition information set is satisfied using the credential from the user who is issued the credential is received;
• and
• a linking processor that checks whether two anonymous credential signature values are linked to each other by using a linking key when the two anonymous credential signature values generated by the user are given.