The system of storage and handling designed to prohibit individual access to certain resources by requiring the presence and actions of at least two authorized persons, each capable of detecting incorrect or unauthorized security procedures with respect to the task being performed.
Sources:
NIST SP 800-172
from
CNSSI 4009-2015 - Adapted
NIST SP 800-172A
from
CNSSI 4009-2015 - Adapted