1. A nonvolatile memory device, comprising: a memory cell array in which memory cells are connected by word lines and bit lines; a page buffer unit comprising page buffer circuits each configured to program encoded data into the memory cells or read data stored in the memory cells; a data conversion unit configured to create random data and output the encoded data by using the random data and decode read data, wherein the random data is generated according to memory block address and word line address; a Y decoder configured to connect the data conversion unit and the page buffer unit in response to address information; and a control unit configured to control the data conversion unit so that the data conversion unit selects set data for encoding or decoding according to the address information.