To provide a memory controller and an operating method thereof which increase randomness of data to be programed, and also provide a memory system, a three-dimensional memory system, a memory card, a solid-state drive and a portable communication device which are provided with the memory controller.

The method for operating a memory controller includes: generating pseudo random numbers by using a seed included in a seed group corresponding to a page to be currently programed among a plurality of seed groups; and randomizing data to be programed into the page by using the pseudo random numbers to output the randomized data.