Question $3[5$ marks$]$: $($Database Security$)$

Consider the following database that contains information about $13$ students. The attacker cannot

directly access the database and can only issue statistical queries $($count and sum$).$ The field

Name is a sensitive one. The attacker has the following background information about one of the

students $($Name$=$Baker, Sex$=$Female, Class$=1980)$

$3$

Name Sex Major Class SAT GP

Allen Female CS $19786003\mathrm{.}4$

Baker Female EE $19805202\mathrm{.}5$

Cook Male EE $19786303\mathrm{.}5$

Davis Female CS $19788004\mathrm{.}0$

Evans Male Bio $19795002\mathrm{.}2$

Frank Male EE $19815803\mathrm{.}0$

Good Male CS $19787003\mathrm{.}8$

Hall Female Psy $19795802\mathrm{.}8$

Iles Male CS $19816003\mathrm{.}2$

Jones Female Bio $19797503\mathrm{.}8$

Kline Female Psy $19815002\mathrm{.}5$

Lane Male EE $19786003\mathrm{.}0$

Moore Male CS $19796503\mathrm{.}5$

a$.[3$ marks$]$ Using statistical queries $($count and sum$)$ and depending on the provided

dataset, how can the attacker know Baker$$s SAT $($Remember that Name is a sensitive

field and cannot be part of any query$)?$

b$.[2$ marks$]$ How can we prevent the attacker from knowing Baker$$s GP$?$