Patent ID: 8549321

Claim:
An IC chip including a first processor and a storage unit that stores a first program, the first program causing the first processor to execute a procedure, the procedure comprising: receiving, from a second processor that executes second programs, an encryption key request signal requesting a communication encryption key to be supplied, the communication encryption key being used to encrypt information to be transferred between the second programs executed on the second processor, the IC chip not including the second processor; generating a communication encryption key every time when the encryption key request signal is received; counting a number of times when the generated communication encryption key is supplied to the second processor; supplying, if the number of times counted does not exceed a predetermined number of times, the generated communication encryption key to the second processor that executes the second programs which send the encryption key request signal; and stopping supply of, if the number of times counted exceeds the predetermined number of times, the generated communication encryption key to the second processor that executes the second programs which send the encryption key request signal, and wherein the second processor specifies an address in a storage of the second processor to which the communication encryption key is to be written, and adds the specified address information to the encryption key request signal to be transmitted to the IC chip, the communication encryption key is written to the address specified when conditions of the number of times are met, and the second processor monitors whether the communication encryption key is written to the address specified and encrypts the information using the communication encryption key when the communication encryption key is written.