Patent attributes
A parity adder obtains a second data by adding a parity for first data to be written to a memory to the first data. An access-key register holds an access key unique to a source of request. A first operating unit obtains a third data by calculating an XOR between the second data and the access key, the access key being set by the source of request for writing data to the memory. A second operating unit obtains a fourth data by calculating an XOR between the access key and the third data. A syndrome calculator calculates a syndrome from the third data, the access key being set by the source of request for reading data from the memory. A determining unit determines whether to output the third data as the first data, based on calculated syndrome.
