Systems engineering activities intended to prevent physical manipulation or delay exploitation of critical program information in U.S. defense systems in domestic and export configurations to impede countermeasure development, unintended technology transfer, or alteration of a system due to reverse engineering.
Sources:
CNSSI 4009-2015
from
DoDI 5200.39
NIST SP 800-160v1r1
from
DoDI 5200.39