1. An apparatus for converting a memory address in a terminal, the apparatus comprising: a random key generator configured to generate a new random key each time the terminal is powered on; an address mapper configured to convert an address of a memory area for data writing or reading using the generated random key and transmit the converted address to a memory, to write data to or read data from the memory area corresponding to the converted address, the memory configured to, in response to receipt of the converted address from the address mapper, write data to or read data from the memory area corresponding to the converted address; and a processor configured to extract the address of the memory area for data writing or reading and transmit the extracted address to the address mapper, wherein if the address of the memory area for data writing or reading is a predetermined address excluded from address conversion, the processor is configured to transmit the address to the memory, to write data to or read data from the memory area corresponding to the address, without transmitting the address to the address mapper.