Unpacking is an art—it is a mental challenge and is one of the most exciting mind games in the reverse engineering field. In some cases, the reverser needs to know the internals of the operating system in order to identify or solve very difficult anti-reversing tricks employed by packers/protectors, patience and cleverness are also major factors in a successful unpack. This challenge involves researchers creating the packers and on the other side, the researchers that are determined to bypass these protections.