Abstract: A method for monitoring memory integrity comprising, receiving a data read access request, updating a data read history register responsive to receiving a data read access request, the update comprising storing a first register value, wherein the first register value is defined by a previous register value and a first symmetric key encryption function, updating a data write history register in further response to receiving the data read access request, the update comprising storing a second register value, wherein the second register value is defined by a previous register value and a second symmetric key encryption function, receiving a data write access request, updating the data read history register responsive to receiving a data write access request, the update comprising storing the first register value, and updating the data write history register in further response to receiving the data write access request, the update comprising storing the second register value.

Abstract: A node 10 is provided with an internal memory 42 for saving a program transmitted from a server 20, a CPU 41 for executing the program saved in the internal memory 42, a hash value calculating section 103 for performing an operation of the program executed by the CPU 41 using a specified hash function when the execution of the program is completed, and a digital signature executing section 104 for digitally signing the program operated using the hash function and the execution result of the program, using a secret key peculiar to the node 10 and saved in a secret key storage 105. Accordingly, there can be provided a microprocessor capable of guaranteeing that the content of a memory is not unjustly falsified during the execution of the program, a node terminal provided with such a microprocessor and capable of proving the execution of the program, a computer system and a program execution proving method.