The present invention provides a means for determining authenticity of a combination of files which are downloaded to a mobile station, and which are related to one another. To achieve the stated object, in a system according to the present invention, mobile station 16, which is capable of running a Java-APP, receives an ADF from CP server device 12. Then mobile station 16 receives a SDF from trusted server device 18, which is identified by data contained in the ADF. Mobile station 16 calculates a hash value of certificate data contained in the ADF, and verifies whether the calculated hash value of the certificate data and a hash value of the certificate data which is contained in the SDF are identical to each other. Next, mobile station 16 receives a JAR file from CP server device 12. Mobile station 16 calculates a hash value of the JAR file, and verifies whether the calculated hash value of the JAR file and a hash value of the JAR file contained in the ADF are identical to each other.