Concealed data matching device, concealed data matching program, and concealed data matching method

A computer-readable and non-transitory storage medium storing a concealed data matching program for causing a computer to execute a process, the computer being configured to be coupled to at least one terminal device, the process comprising:

• generating a determination matrix;
• generating a first random number vector based on the determination matrix;
• transmitting the first random number vector to a first terminal device;
• receiving, from the first terminal device, a first concealed vector obtained by concealing first biometric data and key data that is based on the first random number vector;
• registering, in a memory, the first concealed vector;
• generating a second random number vector based on the determination matrix;
• transmitting the second random number vector to a second terminal device;
• receiving, from the second terminal device, a second concealed vector obtained by concealing second biometric data based on the second random number vector;
• calculating a remainder vector indicating a remainder obtained by dividing a difference between the first concealed vector and the second concealed vector by the determination matrix;
• determining a similarity between the first biometric data and the second biometric data based on the remainder vector;
• extracting the key data from the remainder vector when it is determined that the second biometric data is similar to the first biometric data based on the remainder vector;
• calculating an inter-vector distance between the first biometric data and the second biometric data based on the remainder vector;
• and
• determining the similarity between the first biometric data and the second biometric data based on the inter-vector distance;
• and
• transmitting the key data to the second terminal device when the second biometric data is determined to be similar to the first biometric data based on the inter-vector distance.

A concealed data matching method for causing a computer to execute a process, the computer being configured to be coupled to at least one terminal device, the process comprising:

• generating a determination matrix;
• generating a first random number vector based on the determination matrix;
• transmitting the first random number vector to a first terminal device;
• receiving, from the first terminal device, a first concealed vector obtained by concealing first biometric data and key data that is based on the first random number vector;
• registering, in a memory, the first concealed vector;
• generating a second random number vector based on the determination matrix;
• transmitting the second random number vector to a second terminal device;
• receiving, from the second terminal device, a second concealed vector obtained by concealing second biometric data based on the second random number vector;
• calculating a remainder vector indicating a remainder obtained by dividing a difference between the first concealed vector and the second concealed vector by the determination matrix;
• determining a similarity between the first biometric data and the second biometric data based on the remainder vector;
• extracting the key data from the remainder vector when it is determined that the second biometric data is similar to the first biometric data based on the remainder vector;
• calculating an inter-vector distance between the first biometric data and the second biometric data based on the remainder vector;
• determining the similarity between the first biometric data and the second biometric data based on the inter-vector distance;
• and
• transmitting the key data to the second terminal device when the second biometric data is determined to be similar to the first biometric data based on the inter-vector distance.