According to one embodiment, a memory system is connectable to a host including a first volatile memory and includes a non-volatile memory and a controller. The controller may use a first area of the first volatile memory as a temporary storage memory of data stored in the non-volatile memory and controls the non-volatile memory. The controller generates a first parity by using first data stored in the non-volatile memory and a key value to store the first data and the generated first parity in the first area. In the case of reading the first data stored in the first area, the controller reads the first data and the first parity to verify the read first data using the read first parity and the key value.