Nonvolatile memory device and nonvolatile memory system and random data read method thereof

A method of reading data in a nonvolatile memory system that comprises a plurality of pages including a first page, the first page including a plurality of sectors, the plurality of sectors including a first sector and a second sector, an address of the first sector preceding an address of the second sector, the method comprising:

• receiving a read request for reading data in the second sector, the read request including a page address corresponding to the first page and a sector address corresponding to the second sector;
• generating a first seed based on the page address;
• generating a second seed based on the first seed and on the sector address;
• generating a second random sequence corresponding to the data in the second sector based on the second seed;
• and
• generating output data based on the second random sequence and on the data in the second sector,
• wherein a first random sequence corresponding to data in the first sector is not generated in response to the read request for reading the data in the second sector.