An apparatus and method of converting an address and data of a memory in a terminal. The apparatus includes 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 random key and transmit the converted address to a data converter, and the data converter configured to convert data to be written to the memory using the converted address and convert data to read from the memory using the converted address to original data.