ELECTRONIC AUTHENTICATION SYSTEM, TERMINAL, SERVER, AND ELECTRONIC AUTHENTICATION PROGRAM

PROBLEM TO BE SOLVED: To prevent unauthorized use and such of instructions that are installed in a terminal.SOLUTION: A server comprises: server-side common key holding means that holds a common key; first key generation means that generates a first key from terminal-specific information of a terminal, and the common key; encryption means that encrypts license information with respect to the instructions by using the first key; and license information storage means that stores the terminal-specific information and the encrypted license information in association with each other. The terminal executes the instructions that are installed in the terminal, thereby realizing: terminal-side common key holding means that holds the common key; license information acquisition means that obtains license information associated with the terminal, from license information storage means; second key generation means that generates a second key from the terminal specific information of the terminal, and the common key; decryption means that decrypts the encrypted license information by using the second key; and instruction control means that disables the execution of a predetermined function of the instructions if the license information cannot be decrypted.