An operating method of a memory device, which includes a first memory region and a second memory region, includes reading first data from the first memory region and storing the read first data in a data buffer block, performing a first XOR operation on the first data provided from the data buffer block and second data read from the second memory region to generate first result data, writing the first data stored in the data buffer block in the second memory region, performing a second XOR operation on the first data and the first result data to generate the second data, storing the generated second data in the data buffer block, and writing the second data stored in the data buffer block in the first memory region.