What is used to hide data from unauthorized users by allowing a relation in a database to contain multiple
tuples with the same primary keys with each instance distinguished by a security level?

A.
Data mining

B.
Polyinstantiation

C.
Cell suppression

D.
Noise and perturbation

Explanation:
Polyinstantiation enables a table, which is also known as a relation, to contain multiple tuples with the same
primary keys, with each instance distinguished by a security level. At a lower security level the tuple will not
contain sensitive data and it will effectively be hidden from users who do not have the appropriate access
permissions.
Incorrect Answers:
A: Data mining is the process of analyzing large amounts of data to determine patterns that would not
previously be apparent.
C: Cell suppression is a technique used to hide specific cells in a database that contain information that could
be used in inference attacks.
D: Noise and perturbation is a technique of inserting fake information in a database in an attempt to misdirect
an attacker or create sufficient confuse that the actual attack will not be fruitful.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, pp. 1185, 1186, 1188